Books, journal articles, book chapters, conference papers and other publications are listed below. If you would like a copy of any articles that are not available for downloading, email ben.newell@unsw.edu.au

DOI links to several papers can also be found on the UNSW Research Gateway

Copyright Notice: Some of the documents listed below are available for downloading. These have been provided as a means to ensure timely dissemination of scholarly and technical work on a noncommercial basis. Copyright and all rights therein are maintained by the authors or by other copyright holders, notwithstanding that they have offered their works here electronically. It is understood that all persons copying this information will adhere to the terms and constraints invoked by each author's copyright. These works may not be re-posted without the explicit permission of the copyright holder.


JOURNAL ARTICLES


IN PRESS
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Newell, B.R. and Le Pelley, M.J. (in press) Perceptual but not Complex Moral Judgments can be Biased by Exploiting the Dynamics of Eye-Gaze. Journal of Experimental Psychology: General.
 ABSTRACT 

Can judgments be biased via passive monitoring of eye-gaze? We examined this question using a perceptual discrimination task (Experiment 1) and a complex moral judgment task (Experiment 2). Information about the location of participants’ gaze at particular time-points in a trial was used to prompt responses. When there was no objective perceptual information available to decision-makers, the timing of the prompt had a small, but detectable effect on judgments (Experiment 1). However, this small effect did not scale up to more complex judgments about moral issues (Experiment 2). Our results are consistent with the well-established idea that participants’ judgments are reflected in their eye-gaze, but do not support the recent bold claim of a causal link wherein the timing of a gaze-contingent response-prompt influences complex judgments.


Bolton, A., & Newell, B.R.(in press). Applying Behavioural Science to Government Policy: Finding the ‘Goldilocks Zone’. Journal of Behavioral Economics for Policy.  PDF 
 ABSTRACT 

Using behavioural and social science to inform government policy has the potential to benefit society – provided good scientific practice is adopted. We argue that there are threats to scientific practice in the current Behavioural Insights environment that potentially undermine the validity and usefulness of such work. We discuss what constitutes good science and why this is important, and examine threats to scientific practice from the perspective of scientists conducting experiments on policy initiatives. We aim to assist researchers, governments and policy makers identify conditions where the fit between science and government policy is ‘just right’ (i.e., the ‘Goldilocks Zone’). We discuss potential pathways for developing appropriate infrastructure and procedures to achieve this goal. In particular, we suggest that the early engagement of all parties is necessary to ensure projects incorporate sound science and deliver societal benefit.


Bolton, A., & Newell, B.R.(in press). Finding the ‘Goldilocks Zone’ is both a challenge and an opportunity: A reply to Soon. Journal of Behavioral Economics for Policy.  PDF 
 ABSTRACT 

Using behavioural and social science to inform government policy has the potential to benefit society – provided good scientific practice is adopted. We argue that there are threats to scientific practice in the current Behavioural Insights environment that potentially undermine the validity and usefulness of such work. We discuss what constitutes good science and why this is important, and examine threats to scientific practice from the perspective of scientists conducting experiments on policy initiatives. We aim to assist researchers, governments and policy makers identify conditions where the fit between science and government policy is ‘just right’ (i.e., the ‘Goldilocks Zone’). We discuss potential pathways for developing appropriate infrastructure and procedures to achieve this goal. In particular, we suggest that the early engagement of all parties is necessary to ensure projects incorporate sound science and deliver societal benefit.


Dobrescu, I., Fan. X., Bateman, H., Ortmann, A., Newell, B.R., & Thorp, S. (in press). Retirement savings: A tale of decisions and defaults . Economic Journal.
 ABSTRACT 

This study develops a structural dynamic life-cycle model to examine the behavior of members of an industry-wide pension fund to assess both the prevalence of defaults and their impact on retirement savings. We estimate the model using the simulated method of moments on administrative data from a large Australian pension fund. Our results show that default settings strongly influence wealth accumulation. Such settings are also highly persistent, both over time and across decisions. Overall, the findings suggest that if defaults (particularly the irreversible ones) are not carefully designed, retirement savings can be severely affected.


Hayes, B. K., Ngo, J., Hawkins, G. E., & Newell, B. R. (in press). Causal explanation improves judgment under uncertainty, but rarely in a Bayesian way. Memory & Cognition.  PDF 
 ABSTRACT 

Three studies reexamined the claim that clarifying the causal origin of key statistics can increase normative performance on Bayesian problems involving judgment under uncertainty. Experiments 1 and 2 found that causal explanation did not increase the rate of normative solutions. However, certain types of causal explanation did lead to a reduction in the magnitude of errors in probability estimation. This effect was most pronounced when problem statistics were expressed in percentage formats. Experiment 3 used process-tracing methods to examine the impact of causal explanation of false positives on solution strategies. Changes in probability estimation following causal explanation were the result of a mixture of individual reasoning strategies, including non- Bayesian mechanisms, such as increased attention to explained statistics and approximations of subcomponents of Bayes’ rule. The results show that although causal explanation of statistics can affect the way that a problem is mentally represented, this does not necessarily lead to an increased rate of normative responding.


Konstantinidis, E., Taylor, R. T., & Newell, B. R. (in press). Magnitude and incentives: revisiting the overweighting of extreme events in risky decisions from experience. Psychonomic Bulletin & Review.  PDF 
 ABSTRACT 

Recent experimental evidence in experience based decision-making suggests that people are more risk seeking in the gains domain relative to the losses domain. This critical result is at odds with the standard reflection effect observed in description-based choice and explained by Prospect Theory. The so-called reversed-reflection effect has been predicated on the extreme-outcome rule, which suggests that memory biases affect risky choice from experience. To test the general plausibility of the rule, we conducted two experiments examining how the magnitude of prospective outcomes impacts risk preferences.We found that while the reversed-reflection effect was present with small-magnitude payoffs, using payoffs of larger magnitude brought participants’ behavior back in line with the standard reflection effect. Our results suggest that risk preferences in experience-based decision-making are not only affected by the relative extremeness but also by the absolute extremeness of past events.


Luckman, A, Donkin, C. & Newell, B.R.(in press).People wait longer when the alternative is risky: The relation between preferences in risky and inter-temporal choice. Journal of Behavioral Decision Making.  PDF 
 ABSTRACT 

In two experiments we demonstrate that despite indicating indifference when probed about risk or delay in isolation, when forced to explicitly trade-off between the two, participants prefer delayed over risky rewards. This pattern of findings sets a boundary condition for any common utility-based comparison process involving both risk and delay. Furthermore, this change from indifference-in-isolation to delay-preference-in-a-trade-off strengthens as reward amount increases. Exploratory modelling results suggest that the shift in preference can be explained by allowing for different discount rates for delay-only choices compared to when delay is in competition with risk. This explanation is better than one in which probability weighting is different between risk-only choices and risks considered in the presence of a delay. Together, the empirical and modelling work lays a path for future investigations of why and when people’s evaluation of the properties of risky and delayed choices vary as a function of the alternatives on offer.


Luckman, A, Donkin, C. & Newell, B.R.(in press).Can a single model account for both risky choices and inter-temporal choices? Testing the assumptions underlying models of risky inter-temporal choice. Psychonomic Bulletin & Review.  PDF 
 ABSTRACT 

There is growing interest in modelling how people make choices which involve both risks and delays, i.e. risky inter-temporal choices. Here we investigate an untested assumption underlying several proposed risky inter-temporal choice models: that pure risky choices and pure inter-temporal choices are special cases of risky inter-temporal choice. We test this assumption by presenting a single group of participants with risky choices and inter-temporal choices. We then compare the performance of a model which is fit to both choice types simultaneously, with the performance of separate models fit to the risky choice and intertemporal choice data. We find, using Bayesian model comparison, that the majority of participants are best fit by a single model which incorporates both risky and inter-temporal choices. This result supports the assumption that risky choices and inter-temporal choices may be special cases of risky inter-temporal choice. Our results also suggest that, under the conditions of our experiment, interpretation of monetary value is very similar in risky choices and inter-temporal choices.


2017
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Kalish, M., Newell, B.R., & Dunn, J.C. (2017). More is generally better: Higher working memory capacity does not impair perceptual category learning. Journal of Experimental Psychology: Learning, Memory, & Cognition, 43, 503-514  PDF 
 ABSTRACT 

It is sometimes supposed that category learning involves competing explicit and procedural systems, with only the former reliant on working memory capacity (WMC). In two experiments participants were trained for three blocks on both filtering (often said to be learned explicitly) and condensation (often said to be learned procedurally) category structures. Both experiments (total N = 160) demonstrated that participants with higher WMC tended to be more accurate in condensation tasks, but not less accurate in filtering tasks. Further, state-trace analysis did not find a differential influence of WMC on performance in these tasks. Finally, inspection of the mixture of response strategies at play across the two conditions and three blocks showed only a minor influence of WMC, and then only on later training blocks. The results provide no support for the existence of a ‘system’ of category learning that is independent of working-memory and are instead consistent with most single-system interpretations of category learning.


Kary, A., Hawkins, G. E., Hayes, B. K., & Newell, B. R. (2017). A Bayesian latent mixture model approach to assessing performance in stock-flow reasoning. Judgment and Decision Making, 12, 430-444  PDF 
 ABSTRACT 

People often perform poorly on stock-flow reasoning tasks, with many (but not all) participants appearing to erroneously match the accumulation of the stock to the inflow – a response pattern attributed to the use of a “correlation heuristic”. Efforts to improve understanding of stock-flow systems have been limited by the lack of a principled approach to identifying and measuring individual differences in reasoning strategies. We present a principled inferential method known as Hierarchical Bayesian Latent Mixture Models (HBLMMs) to analyze stock-flow reasoning. HBLMMs use Bayesian inference to classify different patterns of responding as coming from multiple latent populations. We demonstrate the usefulness of this approach using a dataset from a stock-flow drawing task which compared performance in a problem presented in a climate change context, a problem in a financial context, and a problem in which the financial context was used as an analogy to assist understanding in the climate problem. The hierarchical Bayesian model showed that the proportion of responses consistent with the “correlation heuristic” was lower in the financial context and financial analogy context than in the pure climate context. We discuss the benefits of HBLMMs and implications for the role of contexts and analogy in improving stock-flow reasoning.


Martire, K.A, Edmond, G., Navarro, D. & Newell, B.R.(2017). On the likelihood of 'encapsulating all uncertainty' . Science & Justice, 57, 76-79.  PDF 
 ABSTRACT 

The assignment of personal probabilities to form a forensic practitioner's likelihood ratio is a mental operation subject to all the frailties of human memory, perception and judgment. While we agree that beliefs expressed as coherent probabilities are neither ‘right’ nor ‘wrong’ we argue that debate over this fact obscures both the requirement for and consideration of the ‘helpfulness’ of practitioner's opinions. We also question the extent to which a likelihood ratio based on personal probabilities can realistically be expected to ‘encapsulate all uncertainty’. Courts cannot rigorously assess a forensic practitioner's bare assertions of belief regarding evidential strength. At a minimum, information regarding the uncertainty both within and between the opinions of practitioners is required.


Newell, B.R. & Shaw,B. (2017). Priming risky choice: Do risk preferences need inferences? Journal of Behavioural Decision Making, 30, 332–346  PDF 
 ABSTRACT 

The notion that subtle influences, often falling outside awareness, can bias behaviour has a strong grip on both theoretical perspectives and the public imagination. We report three experiments that examined this idea in the context of risky choice. Experiment 1 (N= 100) appeared to find evidence for an interaction whereby participants primed but not reminded of the prime showed an assimilation effect (e.g. participants primed to be risk seeking became more risk seeking) whereas those who were primed and reminded showed a contrast effect (e.g. became less risk seeking). However, two further experiments (N= 180, N= 128) failed to find any evidence for this interaction, and none of the experiments found evidence for the asymmetry in awareness predicted by an ‘unconscious’ assimilation but ‘conscious’ contrast account. The data were analysed using both Null Hypothesis Significance Testing and Bayesian methods, and the implications of the conclusions arising from each are discussed. Whatever one’s statistical predilection, the results imply a reduction of confidence in the belief that risk preferences need no inferences.


Schulze, C, van Ravenzwaaij, D. & Newell, B.R. (2017). Hold it! The influence of lingering rewards on choice diversification and persistence. Journal of Experimental Psychology: Learning, Memory, & Cognition, 43, 1752-1767  PDF 
 ABSTRACT 

Learning to choose adaptively when faced with uncertain and variable outcomes is a central challenge for decision makers. This study examines repeated choice in dynamic probability learning tasks in which outcome probabilities changed either as a function of the choices participants made or independently of those choices. This presence/absence of sequential choice–outcome dependencies was implemented by manipulating a single task aspect between conditions: the retention/withdrawal of reward across individual choice trials. The study addresses how people adapt to these learning environments and to what extent they engage in 2 choice strategies often contrasted as paradigmatic examples of striking violation of versus nominal adherence to rational choice: diversification and persistent probability maximizing, respectively. Results show that decisions approached adaptive choice diversification and persistence when sufficient feedback was provided on the dynamic rules of the probabilistic environments. The findings of divergent behavior in the 2 environments indicate that diversified choices represented a response to the reward retention manipulation rather than to the mere variability of outcome probabilities. Choice in both environments was well accounted for by the generalized matching law, and computational modeling-based strategy analyses indicated that adaptive choice arose mainly from reliance on reinforcement learning strategies.


2016
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Field, S.M., Wagenmakers, E-J., Newell, B.R., Zeelenberg, R., & van Ravenzwaaij, D. (2016). Two Bayesian Tests of the GLOMOsys Model. Journal of Experimental Psychology: General,145, e81-e95.  PDF 
 ABSTRACT 

Priming is arguably one of the key phenomena in contemporary social psychology. Recent retractions and failed replication attempts have led to a division in the field between proponents and skeptics, and reinforce the importance of confirming certain priming effects through replication. In this study, we describe the results of two preregistered replication attempts of one experiment by Förster and Denzler (2012). In both experiments, participants first processed letters either globally or locally, then were tested using a typicality rating task. Bayes factor hypothesis tests were conducted for both experiments: Experiment 1 (N=100) yielded an indecisive Bayes factor of 1.38, indicating that the in-lab data are 1.38 times more likely to have occurred under the null hypothesis than under the alternative. Experiment 2 (N=908) yielded a Bayes factor of 10.84, indicating strong support for the null hypothesis that global priming does not affect participants’ mean typicality ratings. The failure to replicate this priming effect challenges existing support for the GLOMOsys model.


Schulze, C. & Newell, B. R. (2016). Taking the easy way out? Increasing implementation effort reduces probability maximizing under cognitive load. Memory & Cognition, 44, 808-816.  PDF 
 ABSTRACT 

Cognitive load has previously been found to have a positive effect on strategy selection in repeated risky choice. Specifically, whereas inferior probability matching often prevails under single-task conditions, optimal probability maximizing sometimes dominates when a concurrent task competes for cognitive resources. We examined the extent to which this seemingly beneficial effect of increased task demands hinges on the effort required to implement each of the choice strategies. Probability maximizing typically involves a simple repeated response to a single option, whereas probability matching requires choice proportions to be tracked carefully throughout a sequential choice task. Here, we flipped this pattern by introducing a manipulation that made the implementation of maximizing more taxing and, at the same time, allowed decision makers to probability match via a simple repeated response to a single option. The results from two experiments showed that increasing the implementation effort of probability maximizing resulted in decreased adoption rates of this strategy. This was the case both when decision makers simultaneously learned about the outcome probabilities and responded to a dual task (Exp. 1) and when these two aspects were procedurally separated in two distinct stages (Exp. 2). We conclude that the effort involved in implementing a choice strategy is a key factor in shaping repeated choice under uncertainty. Moreover, highlighting the importance of implementation effort casts new light on the sometimes surprising and inconsistent effects of cognitive load that have previously been reported in the literature.


Hayes, B. K., Hawkins, G. E., & Newell, B. R. (2016). Consider the alternative: The effects of causal knowledge on representing and using alternative hypotheses in judgments under uncertainty. Journal of Experimental Psychology: Learning, Memory, and Cognition, 42, 723-739.  PDF 
 ABSTRACT 

Four experiments examined the locus of impact of causal knowledge on consideration of alternative hypotheses in judgments under uncertainty. Two possible loci were examined; overcoming neglect of the alternative when developing a representation of a judgment problem and improving utilization of statistics associated with the alternative hypothesis. In Experiment 1, participants could search for information about the various components of Bayes’s rule in a diagnostic problem. A majority failed to spontaneously search for information about an alternative hypothesis, but this bias was reduced when a specific alternative hypothesis was mentioned before search. No change in search patterns was found when a generic alternative cause was mentioned. Experiments 2a and 2b broadly replicated these patterns when participants rated or made binary judgments about the relevance of each of the Bayesian components. In contrast, Experiment 3 showed that when participants were given the likelihood of the data given a focal hypothesis p(D|H) and an alternative hypothesis p(D|¬H), they gave estimates of p(H|D) that were consistent with Bayesian principles. Additional causal knowledge had relatively little impact on such judgments. These results show that causal knowledge primarily affects neglect of the alternative hypothesis at the initial stage of problem representation.


Schulze, C., & Newell, B. R. (2016). More heads choose better than one: Group decision making can eliminate probability matching. Psychonomic Bulletin & Review, 23, 907–914.  PDF 
 ABSTRACT 

Probability matching is a robust and common failure to adhere to normative predictions in sequential decision making. We show that this choice anomaly is nearly eradicated by gathering individual decision makers into small groups and asking the groups to decide. The group choice advantage emerged both when participants generated responses for an entire sequence of choices without outcome feedback (Exp.1a) and when participants made trial-by-trial predictions with outcome feedback after each decision (Exp.1b). We show that the dramatic improvement observed in group settings stands in stark contrast to a complete lack of effective solitary deliberation. These findings suggest a crucial role of group discussion in alleviating the impact of hasty intuitive responses in tasks better suited to careful deliberation


Newell. B.R., Kary. A., Moore, C. & Gonzalez, C. (2016). Managing the Budget: Stock-flow reasoning and the CO2 Accumulation Problem. Topics in Cognitive Science,8 138-159  PDF 
 ABSTRACT 

The majority of people show persistent poor performance in reasoning about “stock-flow problems” in the laboratory. An important example is the failure to understand the relationship between the “stock” of CO2 in the atmosphere, the “inflow” via anthropogenic CO2 emissions, and the “outflow” via natural CO2 absorption. This study addresses potential causes of reasoning failures in the CO2 accumulation problem and reports two experiments involving a simple re-framing of the task as managing an analogous financial (rather than CO2) budget. In Experiment 1 a financial version of the task that required participants to think in terms of controlling debt demonstrated significant improvements compared to a standard CO2 accumulation problem. Experiment 2, in which participants were invited to think about managing savings, suggested that this improvement was fortuitous and coincidental rather than due to a fundamental change in understanding the stock-flow relationships. The role of graphical information in aiding or abetting stock-flow reasoning was also explored in both experiments, with the results suggesting that graphs do not always assist understanding. The potential for leveraging the kind of reasoning exhibited in such tasks in an effort to change people’s willingness to reduce CO2 emissions is briefly discussed.


Navarro, D.J., Newell, B.R.& Schulze, C. (2016). Learning and choosing in an uncertain world: An investigation of the explore-exploit dilemma in static and dynamic environments. Cognitive Psychology, 85, 43-77  PDF 
 ABSTRACT 

How do people solve the explore-exploit trade-o in a changing environment? In this paper we present experimental evidence from an observe or bet" task, in which people have to determine when to engage in information-seeking behavior and when to switch to reward-taking actions. In particular we focus on the comparison between people's behavior in a changing environment and their behavior in an unchanging one. Our experimental work is motivated by rational analysis of the problem that makes strong predictions about information search and reward seeking in static and changeable environments. Our results show a striking agreement between human behavior and the optimal policy, but also highlight a number of systematic di erences. In particular, we find that while people often employ suboptimal strategies the first time they encounter the learning problem, most people are able to approximate the correct strategy after minimal experience. In order to describe both the manner in which people's choices are similar to but slightly different from an optimal standard, we introduce four process models for the observe or bet task and evaluate them as potential theories of human behavior.


Newell, B.R., Rakow T. Yechiam, E., Sambur, M. (2016). Rare disaster information can increase risk-taking. Nature Climate Change, 6 158-161  PDF 
 ABSTRACT 

The recent increase in the frequency and impact of natural disasters highlights the need to provide the public with accurate information concerning disaster prevalence. Most approaches to this problem assume that providing summaries of the nature and scale of disasters will lead people to reduce their exposure to risk. Herewe present experimental evidence that such ex post ‘news reports’ of disaster occurrences can increase the tolerance for risk-taking (which implies that rare events are underweighted). This result is robust across several hundred rounds of choices in a simulated microworld, persists even when the long-run expected value of risky choices is substantially lower than safe choices, and is contingent on providing risk information about disasters that have been (personally) experienced and those that have been avoided (‘forgone’ outcomes). The results suggest that augmenting personal experience with information summaries of the number of adverse events (for example, storms, floods) in dierent regions may, paradoxically, increase the appeal of a disaster-prone region. This finding implies a need to communicate long-term trends in severe climatic events, thereby reinforcing the accumulation of events, and the increase in their associated risks, across time.


De Zilva, D., Newell, B.R., & Mitchell, C.J. (2016). Multiple Context Mere Exposure: Examining the Limits of Liking. Quarterly Journal of Experimental Psychology,69 521-534  PDF 
 ABSTRACT 

Recent evidence suggests that increased liking of exposed stimuli—a phenomenon known as the mere exposure effect—is dependent on experiencing the stimuli in the same context at exposure and test. Three experiments extended this work by examining the effect of presenting target stimuli in single and multiple exposure contexts. Target face stimuli were repeatedly paired with nonsense words, which took the role of contexts, across exposure. On test, the mere exposure effect was found only when the target face stimuli were presented with nonsense word cues (contexts) with which they had been repeatedly paired. The mere exposure effect was eliminated when exposure to target face stimuli with the nonsense word cues (contexts) was minimal, despite the overall number of exposures to the target face being equated across single- and multiple-context exposure conditions. The results suggest that familiarity of the relationship between stimuli and their context, not simply familiarity of the stimuli themselves, leads to liking. The finding supports a broader framework, which suggests that liking is partly a function of the consistency between past and present experiences with a target stimulus.


Bateman, H., Dobrescu, I., Ortmann, A., Newell, B. R., & Thorp, S. (2016). As easy as pie: How retirement savers use prescribed investment disclosures. Journal of Economic Behavior & Organization, 121 60-76.  PDF 
 ABSTRACT 

Using a laboratory experiment, we study how retirement plan members choose investmentoptions using five information items prescribed by regulators. We found that asset alloca-tion information for pre-mixed investment options – normally presented as a pie chart ora table – had the largest impact on choices. Participants preferred investment options withmore, and more evenly weighted, asset class allocations. This novel application of a 1/nstrategy differs significantly from the existing findings of naïve diversification in ‘mix-it-yourself’ conditions where participants spread resources evenly across funds or categories.When asset allocation information was included, coefficients on return and risk informa-tion had unexpected signs, but when asset allocation was omitted, participants preferredoptions with high Sharpe ratios. We also demonstrate that none of the five prescribedinformation items was significant in explaining individual choices of more than 35% ofparticipants. These findings highlight that information contained in prescribed investmentdisclosures might not be used in the manner intended by the regulator. The results raiseimportant methodological questions about the way ‘user-friendly’ information prescribedby regulators is validated before being legislated.


2015
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Rakow, T., Newell, B.R., & Wright, L. (2015) Foregone But Not Forgotten: The Effect of Partial and Full Feedback in Harsh and Kind Environments. Psychonomic Bulletin & Review, 22 1807-1813.  PDF 
 ABSTRACT 

In a perfect world, the choice of any course of action would lead to a satisfactory outcome, and we would obtain feedback about both our chosen course and those we have chosen to forgo. In reality, however, we often face harsh environments in which we can only minimize losses, and we receive impoverished feedback. In these studies, we examined how decision makers dealt with these challenges in a simple task in which we manipulated three features of the decision: The outcomes from the available options were either mostly positive or mostly negative (kind or harsh environment); feedback was either full or partial (outcomes revealed for all options or only for the chosen option); and for the final 20 trials in a sequence, participants either chose on each trial or set an advance-directive policy. The propensity to choose the better option was explained by several factors: Full feedback was more beneficial in harsh than in kind environments; policy decisions encouraged better decisions and ameliorated the adverse impact of a harsh environment; and beliefs about the value of strategy diversification predicted switch rates and choice quality. The results suggest a subtle interplay between bottom-up and top-down processes: Although harsh environments encourage poor choices, and some decision makers choose less well than others, this need not imply that the decision maker has failed to identify the better option.


Bonner, C., Jansen, J., Newell, B.R., et al. (2015). Is the 'heart age' concept helpful or harmful compared to absolute cardiovascular disease risk? An experimental study. Medical Decision Making, 35, 959-966.  PDF 
 ABSTRACT 

Background. Cardiovascular disease (CVD) prevention guidelines are generally based on the absolute risk of a CVD event, but there is increasing interest in using ‘heart age’ to motivate lifestyle change when absolute risk is low. Previous studies have not compared heart age to 5-year absolute risk, or investigated the impact of younger heart age, graphical format, and numeracy. Objective. Compare heart age versus 5-year absolute risk on psychological and behavioral outcomes. Design. 2 (heart age, absolute risk) × 3 (text only, bar graph, line graph) experiment. Setting. Online. Participants. 570 Australians aged 45–64 years, not taking CVD-related medication. Intervention. CVD risk assessment. Measurements. Intention to change lifestyle, recall, risk perception, emotional response, perceived credibility, and lifestyle behaviors after 2 weeks. Results. Most participants had lifestyle risk factors (95%) but low 5-year absolute risk (94%). Heart age did not improve lifestyle intentions and behaviors compared to absolute risk, was more often interpreted as a higher-risk category by low-risk participants (47% vs 23%), and decreased perceived credibility and positive emotional response. Overall, correct recall dropped from 65% to 24% after 2 weeks, with heart age recalled better than absolute risk at 2 weeks (32% vs 16%). These results were found across younger and older heart age results, graphical format, and numeracy. Limitations. Communicating CVD risk in a consultation rather than online may produce different results. Conclusions. There is no evidence that heart age motivates lifestyle change more than 5-year absolute risk in individuals with low CVD risk. Five-year absolute risk may be a better way to explain CVD risk, because it is more credible, does not inflate risk perception, and is consistent with clinical guidelines that base lifestyle and medication recommendations on absolute risk.


McDonald, R., Chai, H-Y, & Newell, B. R. (2015). Personal experience and the 'psychological distance' of climate change: An integrative review. Journal of Environmental Psychology, 44 109-118.  PDF 
 ABSTRACT 

Studies examining personal experiences of climate change-related events highlight the potential to encourage climate action by framing it as happening now, in your neighborhood, and affecting people like you e that is, psychologically close. We compare this literature to studies that examine psychological distance. The review reveals a disconnect: while studies of personal experience suggest merits of reducing psychological distance, other studies present a more nuanced picture in which psychological proximity does not always lead to more concern about or action on climate change. Despite its emphasis, psychological distance has not been widely studied in experimental work in the climate change context, and there is a need for more systematic examination of its effects across a range of mitigation and adaptation actions. Further, our review identifies potential pitfalls associated with decreasing psychological distance, such as fear and avoidance. Finally, we provide preliminary recommendations for optimal ways to bring climate change “home.”


Schulze, C., & Newell, B. R. (2015). Compete, coordinate, and cooperate: How to exploit uncertain environments with social interaction. Journal of Experimental Psychology: General, 144, 967-981.  PDF 
 ABSTRACT 

Countless decisions, from the trivial to the crucial, are made in complex social contexts while facing uncertain consequences. Yet a large portion of decision making research focuses on either the effects of social interaction or the effects of environmental uncertainty by examining strategic games against others or individual games against nature. Drawing a connection between these approaches, the authors extend a standard individual choice paradigm to include social interaction with 1 other person. In this paradigm, 2 competing decision makers repeatedly select among 2 options, each offering a particular probability of a fixed payoff. When both players choose the same, correct option, the payoff is evenly split; when they choose different options, the player choosing the correct option receives the full payoff. The addition of this social dimension gives players an opportunity to fully exploit an uncertain environment via cooperation—by consistently choosing opposite options. We present 2 experiments that manipulate environmental (Experiment 1) and social (Experiment 2) aspects of the paradigm. In Experiment 1, the outcome probabilities were either known or unknown to participants; in Experiment 2, participants’ attention was drawn to individual or group gains by introducing either within- or between-groups competition. Efficient cooperation did not emerge spontaneously in Experiment 1. Instead, most people probability maximized, mirroring the behavior observed in individual choice. By contrast, betweengroups competition in Experiment 2 facilitated efficient— but not always equitable— exploitation of uncertain environments. This work links the concepts of individual risky choice and strategic decision making under both environmental and social uncertainty.


Stewart, N., Ungemach, C., Harris, A. J. L., Bartels, D. M., Newell, B. R., Paolacci, G., & Chandler, J. (2015). The average laboratory samples a population of 7,300 Amazon Mechanical Turk workers. Judgment and Decision Making, 10, 479-491.  PDF 
 ABSTRACT 

Using capture-recapture analysis we estimate the effective size of the active Amazon Mechanical Turk (MTurk) population that a typical laboratory can access to be about 7,300 workers. We also estimate that the time taken for half of the workers to leave the MTurk pool and be replaced is about 7 months. Each laboratory has its own population pool which overlaps, often extensively, with the hundreds of other laboratories using MTurk. Our estimate is based on a sample of 114,460 completed sessions from 33,408 unique participants and 689 sessions across seven laboratories in the US, Europe, and Australia from January 2012 to March 2015.


Hawkins, G., Hayes, B.K., Donkin, C., Pasqualino, M., & Newell, B.R. (2015). A Bayesian latent mixture model analysis shows that informative samples reduce base rate neglect. Decision, 2, 306-318  PDF 
 ABSTRACT 

We examined the conditions under which sampling information from different probability distributions reduces base-rate neglect in intuitive probability judgments. To assess the impact of our manipulations, we employed a novel Bayesian latent-mixture model analysis that allowed us to quantify evidence for base-rate neglect. Experience with samples from the posterior distribution in the form of sequential sampling and a descriptive summary tally both markedly reduced base-rate neglect relative to baseline, and the summary tally improved performance over sequential sampling. Experience with samples from the prior distribution reduced base-rate neglect when conveyed as a descriptive summary, but not when sequentially sampled over time. The results indicate that (a) a summary of sample information can be more beneficial to judgment performance than sequentially sampling the same information, and (b) the benefits of sampling experience are more likely to be realized when the contents of the sample are perceived as directly relevant to the judgment problem. These findings help to clarify when and how sampling experience facilitates intuitive probability judgment.


Rakow, T., Heard, C.L. & Newell, B.R. (2015). Meeting three challenges in risk communication: phenomena, numbers and emotions. Policy Insights from the Behavioral and Brain Sciences, 2, 147-156  PDF 
 ABSTRACT 

Risk communication takes many forms, can serve a number of different purposes, and can inform people about a wide variety of risks. We outline three challenges that must often be met when communicating about risk, irrespective of the form or purpose of that communication, or the type of risk that this involves. The first challenge is how best to help people understand the phenomenology of the risks that they are exposed to: The nature of the risk, the mechanism(s) by which they arise, and, therefore, what can be done to manage these risks. Each risk has its own phenomenology; therefore, rather than offering generic guidance, we illustrate with the case of climate change risk how evidence from behavioral science can guide the design of messages about risk. The second challenge is how best to present quantitative risk information about risk probabilities. Here, there is potential for: Ambiguity, difficulty in evaluating quantitative information, and weak numeracy skills among those being targeted by a message. We outline when each of these difficulties is most likely to arise as a function of the precision of the message and show how messages that cover multiple levels of precision might ameliorate these difficulties. The third challenge is the role played by people’s emotional reactions to the risks that they face and to the messages that they receive about these risks. Here, we discuss the pros and cons of playing up, or playing down, the emotional content of risk communication messages.


Mehlhorn, K., Newell, B.R., Todd, P.M., Lee, M.D., Morgan, K. Braithwaite, V.A., Hausmann, D., Fielder, K., & Gonzalez, C. (2015). Unpacking the exploration-exploitation tradeoff: A synthesis of human and animal literatures. Decision, 2, 191-215  PDF 
 ABSTRACT 

Many decisions in the lives of animals and humans require a fine balance between the exploration of different options and the exploitation of their rewards. Do you buy the advertised car, or do you test drive different models? Do you continue feeding from the current patch of flowers, or do you fly off to another one? Do you marry your current partner, or try your luck with someone else? The balance required in these situations is commonly referred to as the exploration–exploitation tradeoff. It features prominently in a wide range of research traditions, including learning, foraging, and decision making literatures. Here, we integrate findings from these and other often-isolated literatures in order to gain a better understanding of the possible tradeoffs between exploration and exploitation, and we propose new theoretical insights that might guide future research. Specifically, we explore how potential tradeoffs depend on (a) the conceptualization of exploration and exploitation; (b) the influencing environmental, social, and individual factors; (c) the scale at which exploration and exploitation are considered; (d) the relationship and types of transitions between the 2 behaviors; and (e) the goals of the decision maker. We conclude that exploration and exploitation are best conceptualized as points on a continuum, and that the extent to which an agent’s behavior can be interpreted as exploratory or exploitative depends upon the level of abstraction at which it is considered


Guney, S. & Newell, B.R. (2015). Overcoming ambiguity aversion through experience. Journal of Behavioral Decision Making,28 188-199.  PDF
 ABSTRACT 

Ambiguity is often characterized with unknown probability distributions (for potential outcomes), which people avoid while making decisions. Existing literature shows that ambiguity aversion often persists even when these probability distributions are explicitly described to decision makers. We test the hypothesis that exposure to these probability distributions via sampling experience, rather than description, will lead to a reduction in ambiguity aversion. We used the classic two-colour Ellsberg task in which the participants were asked to choose to bet on either a risky bet (i.e. probabilities were known) or (versions of) an ambiguous bet (i.e. exact probabilities were unknown). Different probability distributions, each providing subtly different information about the underlying properties of the ambiguous bet, were either experienced through sampling or described to participants prior to choice. Overall, the results indicated that people demonstrated ambiguity-neutral attitudes when the underlying probability distributions were experienced. In contrast, when described, attitudes toward ambiguity changed as a function of the type of probability distribution. Additional analyses confirmed that decision makers were less likely to be ambiguity-averse when their individual experiences were positive during sampling trials (i.e. observing distributions with winning being more likely or more frequent).


Donkin, C., Newell, B.R., Kalish, M., Dunn, J.C., & Nosofsky, R.M. (2015). Identifying Strategy Use in Category Learning Tasks: A Case for More Diagnostic Data and Models. Journal of Experimental Psychology: Learning, Memory, & Cognition, 41, 933-948  PDF 
 ABSTRACT 

The strength of conclusions about the adoption of different categorization strategies—and their implications for theories about the cognitive and neural bases of category learning— depend heavily on the techniques for identifying strategy use. We examine performance in an often-used “informationintegration” category structure and demonstrate that strategy identification is affected markedly by the range of models under consideration, the type of data collected, and model-selection techniques. We use a set of 27 potential models that represent alternative rule-based and information-integration categorization strategies. Our experimental paradigm includes the presentation of nonreinforced transfer stimuli that improve one’s ability to discriminate among the predictions of alternative models. Our modelselection techniques incorporate uncertainty in the identification of individuals as either rule-based or information-integration strategy users. Based on this analysis we identify 48% of participants as unequivocally using an information-integration strategy. However, adopting the standard practice of using a restricted set of models, restricted data, and ignoring the degree of support for a particular strategy, we would typically conclude that 89% of participants used an information-integration strategy. We discuss the implications of potentially erroneous strategy identification for the security of conclusions about the categorization capabilities of various participant and patient groups


Lewandowsky, S., Oreskes, N., Risbey, J.S., Newell, B.R. & Smithson, M. (2015). Seepage: Climate change denial and its effect on the scientific community. Global Environmental Change, 33, 1-13  PDF 
 ABSTRACT 

Vested interests and political agents have long opposed political or regulatory action in response to climate change by appealing to scientific uncertainty. Here we examine the effect of such contrarian talking points on the scientific community itself. We show that although scientists are trained in dealing with uncertainty, there are several psychological reasons why scientists may nevertheless be susceptible to uncertainty-based argumentation, even when scientists recognize those arguments as false and are actively rebutting them. Specifically, we show that prolonged stereotype threat, pluralistic ignorance, and a form of projection (the third-person effect) may cause scientists to take positions that they would be less likely to take in the absence of outspoken public opposition. We illustrate the consequences of seepage from public debate into the scientific process with a case study involving the interpretation of temperature trends from the last 15 years. We offer ways in which the scientific community can detect and avoid such inadvertent seepage.


Schulze, C., van Ravenzwaaij, D., & Newell, B. R. (2015). Of matchers and maximizers: How competition shapes choice under risk and uncertainty. Cognitive Psychology, 78, 78–98  PDF 
 ABSTRACT 

In a world of limited resources, scarcity and rivalry are central challenges for decision makers—animals foraging for food, corporations seeking maximal profits, and athletes training to win, all strive against others competing for the same goals. In this article, we establish the role of competitive pressures for the facilitation of optimal decision making in simple sequential binary choice tasks. In two experiments, competition was introduced with a computerized opponent whose choice behavior reinforced one of two strategies: If the opponent probabilistically imitated participant choices, probability matching was optimal; if the opponent was indifferent, probability maximizing was optimal. We observed accurate asymptotic strategy use in both conditions irrespective of the provision of outcome probabilities, suggesting that participants were sensitive to the differences in opponent behavior. An analysis of reinforcement learning models established that computational conceptualizations of opponent behavior are critical to account for the observed divergence in strategy adoption. Our results provide a novel appraisal of probability matching and show how this individually ‘irrational’ choice phenomenon can be socially adaptive under competition.


Newell, B.R. (2015). Wait! Just let me NOT think about that for a minute: What role do implicit processes play in higher level cognition? Current Directions in Psychological Science, 24, 65-70  PDF 
 ABSTRACT 

The belief that in certain situations we are better off not thinking has anecdotal resonance and appeals to our tendency to follow a “law of least effort.” But is it good advice? In this review, I examine recent work from two domains of higher-level cognition—perceptual category learning and decision making—in which similar claims have been made about the benefits of disengaging explicit thought to allow for the operation of superior implicit processes. A reevaluation of this literature suggests a less appealing but perhaps also less surprising conclusion: Complex tasks appear to require explicit thought, and there is little reason to think that not thinking is optimal in these situations. Far from offering a negative conclusion, this perspective emphasizes not only the powers of human cognition but also our ability to explain our behavior without recourse to the “black box” of the unconscious.


Yechiam, E., Rakow, T., & Newell, B.R. (2015). Super-underweighting of rare events with repeated descriptive summaries. Journal of Behavioural Decision Making, 28, 67-75  PDF 
 ABSTRACT 

Field studies suggest that providing summarized information concerning the prevalence of risks can increase risk taking when the hazard is rare. We study a simple experimental model of this phenomenon based on repeated descriptive summaries of past outcomes. Under cumulative prospect theory and experience-sampling models, descriptions of rare events should increase the weighting of rare events. On the other hand, if individuals are sensitive to the frequency of events, then event summaries are expected to accentuate the underweighting of rare events despite adding descriptive information. These contrasting predictions were examined in three experiments using a multi-alternative decision task with two sets of options: safe and risky. In all three experiments, repeated descriptive summaries of past outcomes from all alternatives or from a randomly drawn alternative were found to accentuate the underweighting of rare events by a similar amount. The results shed light on the role of frequency-based judgments in the extreme underweighting of rare events and highlight that providing information about the incidence of rare hazards can have the unintended effect of increasing, rather than decreasing, people’s propensity to take risks



2014
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Hurlstone, M., Lewandowsky, S., Newell, B.R., & Sewell, B. (2014). The effect of framing and normative messages in building support for climate policies. PLOS One e114335  PDF
 ABSTRACT 

Deep cuts in greenhouse gas emissions are required to mitigate climate change. However, there is low willingness amongst the public to prioritise climate policies for reducing emissions. Here we show that the extent to which Australians are prepared to reduce their country’s CO2 emissions is greater when the costs to future national income are framed as a ‘‘foregone-gain’’—incomes rise in the future but not by as much as in the absence of emission cuts—rather than as a ‘‘loss’’— incomes decrease relative to the baseline expected future levels (Studies 1 & 2). The provision of a normative message identifying Australia as one of the world’s largest CO2 emitters did not increase the amount by which individuals were prepared to reduce emissions (Study 1), whereas a normative message revealing the emission policy preferences of other Australians did (Study 2). The results suggest that framing the costs of reducing emissions as a smaller increase in future income and communicating normative information about others’ emission policy preferences are effective methods for leveraging public support for emission cuts.


Hayes, B.K., Hawkins, G., Newell, B.R., Pasqualino, M. & Rehder, B. (2014). The role of causal models in multiple judgments under uncertainty. Cognition, 133, 611-620  PDF
 ABSTRACT 

Two studies examined a novel prediction of the causal Bayes net approach to judgments under uncertainty, namely that causal knowledge affects the interpretation of statistical evidence obtained over multiple observations. Participants estimated the conditional probability of an uncertain event (breast cancer) given information about the base rate, hit rate (probability of a positive mammogram given cancer) and false positive rate (probability of a positive mammogram in the absence of cancer). Conditional probability estimates were made after observing one or two positive mammograms. Participants exhibited a causal stability effect: there was a smaller increase in estimates of the probability of cancer over multiple positive mammograms when a causal explanation of false positives was provided. This was the case when the judgments were made by different participants (Experiment 1) or by the same participants (Experiment 2). These results show that identical patterns of observed events can lead to different estimates of event probability depending on beliefs about the generative causes of the observations.


Lee, M.D., Newell, B.R., & Vandekerckhove, J. (2014). Modeling the adaptation of search termination in human decision making. Decision, 4, 223-251  PDF
 ABSTRACT 

We study how people terminate their search for information when making decisions in a changing environment. In 3 experiments, differing in the cost of search, participants made a sequence of 2-alternative decisions, based on the information provided by binary cues they could search. Whether limited or extensive search was required to maintain accurate decisions changed across the course of the experiment, but was not indicated to participants. We find large individual differences but that, in general, the extent of search is changed in response to environmental change, and is not necessarily triggered by a reduction in accuracy. We then examine the ability of 4 models to account for individual participant behavior, using a generalization measure that tests model predictions. Two of the models use reinforcement learning, and differ in whether they use error or both error and effort signals to control how many cues are searched. The other 2 models use sequential sampling processes, and differ in the regulatory mechanisms they use to adjust the decision thresholds that control the extent of search. We find that error-based reinforcement learning is usually an inadequate account of behavior, especially when search is costly. We also find evidence in the model predictions for the use of confidence as a regulatory variable. This provides an alternative theoretical approach to balancing error and effort, and highlights the possibility of hierarchical regulatory mechanisms that lead to delayed and abrupt changes in the extent of search.


Newell, B.R., McDonald, R.I., Brewer, M., & Hayes, B.K. (2014) The Psychology of Environmental Decisions. Annual Review of Environment and Resources, 39, 443-467  PDF
 ABSTRACT 

Humanity faces an unprecedented set of global environmental problems.We argue that to promote pro-environmental decisions and to achieve public consensus on the need for action we must address individual and collective understanding (cognition) of environmental problems, as well as individual and collective commitments to take action to mitigate or prevent those problems. We review literature pertaining to psychological predispositions, mental models, framing, psychological distance, and the social context of decisions that help elucidate how these goals of cognition and commitment can be achieved. This article reveals the complex and multiply determined nature of environmental decisions. However, we argue that this complexity points to opportunities to reduce the inherent uncertainty surrounding global environmental challenges via appeals to the psychological mechanisms that underpin our decisions.


Newell, B.R. & Shanks, D.R. (2014). Unconscious Influences on Decision Making: A Critical Review. Behavioral and Brain Sciences, 37, 1-63  PDF
 ABSTRACT 

To what extent do we know our own minds when making decisions? Variants of this question have preoccupied researchers in a wide range of domains, from mainstream experimental psychology (cognition, perception, social behavior) to cognitive neuroscience and behavioral economics. A pervasive view places a heavy explanatory burden on an intelligent cognitive unconscious, with many theories assigning causally effective roles to unconscious influences. This article presents a novel framework for evaluating these claims and reviews evidence from three major bodies of research in which unconscious factors have been studied: multiple-cue judgment, deliberation without attention, and decisions under uncertainty. Studies of priming (subliminal and primes-to-behavior) and the role of awareness in movement and perception (e.g., timing of willed actions, blindsight) are also given brief consideration. The review highlights that inadequate procedures for assessing awareness, failures to consider artifactual explanations of “landmark” results, and a tendency to uncritically accept conclusions that fit with our intuitions have all contributed to unconscious influences being ascribed inflated and erroneous explanatory power in theories of decision making. The review concludes by recommending that future research should focus on tasks in which participants’ attention is diverted away from the experimenter’s hypothesis, rather than the highly reflective tasks that are currently often employed.


Shanks, D.R. & Newell, B.R. & (2014). The primacy of conscious decision making. Behavioral and Brain Sciences, 37, 1-63  PDF
 ABSTRACT 

To what extent do we know our own minds when making decisions? Variants of this question have preoccupied researchers in a wide range of domains, from mainstream experimental psychology (cognition, perception, social behavior) to cognitive neuroscience and behavioral economics. A pervasive view places a heavy explanatory burden on an intelligent cognitive unconscious, with many theories assigning causally effective roles to unconscious influences. This article presents a novel framework for evaluating these claims and reviews evidence from three major bodies of research in which unconscious factors have been studied: multiple-cue judgment, deliberation without attention, and decisions under uncertainty. Studies of priming (subliminal and primes-to-behavior) and the role of awareness in movement and perception (e.g., timing of willed actions, blindsight) are also given brief consideration. The review highlights that inadequate procedures for assessing awareness, failures to consider artifactual explanations of “landmark” results, and a tendency to uncritically accept conclusions that fit with our intuitions have all contributed to unconscious influences being ascribed inflated and erroneous explanatory power in theories of decision making. The review concludes by recommending that future research should focus on tasks in which participants’ attention is diverted away from the experimenter’s hypothesis, rather than the highly reflective tasks that are currently often employed.


Lewandowsky, S., Risbey, J.S., Smithson, M., Newell, B.R., & Hunter, J. (2014) Scientific Uncertainty and Climate Change: Part I. Uncertainty and Unabated Emissions. Climatic Change, 124, 21-37  PDF
 ABSTRACT 

Uncertainty forms an integral part of climate science, and it is often used to argue against mitigative action. This article presents an analysis of uncertainty in climate sensitivity that is robust to a range of assumptions. We show that increasing uncertainty is necessarily associated with greater expected damages from warming, provided the function relating warming to damages is convex. This constraint is unaffected by subjective or cultural risk-perception factors, it is unlikely to be overcome by the discount rate, and it is independent of the presumed magnitude of climate sensitivity. The analysis also extends to “second-order” uncertainty; that is, situations in which experts disagree. Greater disagreement among experts increases the likelihood that the risk of exceeding a global temperature threshold is greater. Likewise, increasing uncertainty requires increasingly greater protective measures against sea level rise. This constraint derives directly from the statistical properties of extreme values. We conclude that any appeal to uncertainty compels a stronger, rather than weaker, concern about unabated warming than in the absence of uncertainty.


Lewandowsky, S., Risbey, J.S., Smithson, M., Newell, B.R. (2014). Scientific Uncertainty and Climate Change: Part II. Uncertainty and Mitigation. Climatic Change, 124, 39-52  PDF
 ABSTRACT 

In public debate surrounding climate change, scientific uncertainty is often cited in connection with arguments against mitigative action. This article examines the role of uncertainty about future climate change in determining the likely success or failure of mitigative action. We show by Monte Carlo simulation that greater uncertainty translates into a greater likelihood that mitigation efforts will fail to limit global warming to a target (e.g., 2 ◦C). The effect of uncertainty can be reduced by limiting greenhouse gas emissions. Taken together with the fact that greater uncertainty also increases the potential damages arising from unabated emissions (Lewandowsky et al. 2014), any appeal to uncertainty implies a stronger, rather than weaker, need to cut greenhouse gas emissions than in the absence of uncertainty


van Ravenzwaaij, D., Moore, C. P., Lee, M. D., & Newell, B. R. (2014). A Hierarchical Bayesian Modeling Approach to Searching and Stopping in Multi–Attribute Judgment. Cognitive Science, 38, 1384-1405  PDF
 ABSTRACT 

Abstract In most decision-making situations, there is a plethora of information potentially available to people. Deciding what information to gather and what to ignore is no small feat. How do decision makers determine in what sequence to collect information and when to stop? In two experiments, we administered a version of the German cities task developed by Gigerenzer and Goldstein (1996), in which participants had to decide which of two cities had the larger population. Decision makers were not provided with the names of the cities, but they were able to collect different kinds of cues for both response alternatives (e.g., “Does this city have a university?”) before making a decision. Our experiments differed in whether participants were free to determine the number of cues they examined. We demonstrate that a novel model, using hierarchical latent mixtures and Bayesian inference (Lee & Newell, 2011) provides a more complete description of the data from both experiments than simple conventional strategies, such as the take–the–best or the Weighted Additive heuristics.


Bateman, H., Deetlefs, A.M.J., Dobrescu, L.I., Newell, B.R., Ortmann, A., & Thorp, S. (2014). Just interested or getting involved? An analysis of superannuation attitudes and actions. Economic Record, 90, 160-178  PDF
 ABSTRACT 

Low levels of non-default decision-making among superannuation members in Australia are assumed to be evidence of a lack of interest and capability. Using member records and survey data from a large Australian superannuation fund, we test the relationship between attitudes towards retirement savings and observable levels of non-default activities (such as making voluntary contributions, choosing or changing investment options and changing insurance cover). Additional retirement savings contributions by permanent staff are more likely if the staff member is very likely to recommend their superannuation fund. Individuals who rate their own personal interest in superannuation affairs as very high are more likely to be active online. This, however, does not extend to choosing a nondefault investment or purchasing additional insurance, where we find no differences between the highly interested and the disengaged. These findings, together with several other differences related to demographics and employment conditions, show that nondefault activity is not a reliable proxy for member engagement.


Dunn, J.C., Kalish, M., & Newell, B.R., (2014). State-Trace Analysis can be an appropriate tool for assessing the number of cognitive systems: A reply to Ashby (2014). Psychonomic Bulletin & Review, 21, 947-954  PDF
 ABSTRACT 

Ashby (2014) has argued that state-trace analysis (STA) is not an appropriate tool for assessing the number of cognitive systems, because it fails in its primary goal of distinguishing single-parameter and multiple-parameter models. We show that this is based on a misunderstanding of the logic of STA, which depends solely on nearly universal assumptions about psychological measurement and clearly supersedes inferences based on functional dissociation and the analysis of interactions in analyses of variance. We demonstrate that STA can be used to draw inferences concerning the number of latent variables mediating the effects of a set of independent variables on a set of dependent variables. We suggest that STA is an appropriate tool to use when making arguments about the number of cognitive systems that must be posited to explain behavior. However, no statistical or inferential procedure is able to provide definitive answers to questions about the number of cognitive systems, simply because the concept of a “system” is not defined in an appropriate way


Bonner, C., Jansen, J., Newell, B.R., Irwig, L., Glasziou, P., Doust, J., Dhillon, H., & McCaffery, K. (2014). I don't believe it, but I'd better do something about it: Patient experiences of online 'heart age' risk calculators. Journal of Medical Internet Research, 16(5), e120  PDF
 ABSTRACT 

Health risk calculators are widely available on the Internet, including cardiovascular disease (CVD) risk calculators that estimate the probability of a heart attack, stroke, or death over a 5- or 10-year period. Some calculators convert this probability to “heart age”, where a heart age older than current age indicates modifiable risk factors. These calculators may impact patient decision making about CVD risk management with or without clinician involvement, but little is known about how patients use them. Previous studies have not investigated patient understanding of heart age compared to 5-year percentage risk, or the best way to present heart age


Martire, K.A., Kemp, R.I., Sayle, M., & Newell, B.R. (2014). On the presentation of likelihood ratios in forensic science evidence: Presentation formats and the weak evidence effect. Forensic Science International, 240, 61-68  PDF
 ABSTRACT 

Likelihood ratios are increasingly being adopted to convey expert evaluative opinions to courts. In the absence of appropriate databases, many of these likelihood ratios will include verbal rather than numerical estimates of the support offered by the analysis. However evidence suggests that verbal formulations of uncertainty are a less effective form of communication than equivalent numerical formulations. Moreover, when evidence strength is low a misinterpretation of the valence of the evidence – a ‘‘weak evidence effect’’ – has been found. We report the results of an experiment involving N = 404 (student and online) participants who read a brief summary of a burglary trial containing expert testimony. The expert evidence was varied across conditions in terms of evidence strength (low or high) and presentation method (numerical, verbal, table or visual scale). Results suggest that of these presentation methods, numerical expressions produce belief-change and implicit likelihood ratios which were most commensurate with those intended by the expert and most resistant to the weak evidence effect. These findings raise questions about the extent to which low strength verbal evaluative opinions can be effectively communicated to decision makers at trial


Newell, B.R., & Shanks., D.R. (2014). Prime Numbers: Anchoring and its Implications for Theories of Behavior Priming. Social Cognition, 32, 88-108  PDF
 ABSTRACT 

Subtle primes can influence behavior, often in ways that seem irrational. Anchoring provides a compelling illustration of this: judgments can be influenced by anchors even when the anchors are known to be irrelevant and uninformative. In this article, we selectively examine the anchoring literature in order to evaluate a theoretical framework which has been employed to interpret many social and other priming effects. In this framework, primes are assumed to have broad effects, influencing a wide range of possible downstream behaviors, and these influences are largely automatic. The anchoring literature supports neither of these hypotheses. Anchors have narrow effects on behavior with little transfer across judgments, these effects can be controlled, and deliberate engagement with the anchor is a prerequisite for obtaining influences on later judgments. We question whether priming studies reveal evidence for the sort of automatic and consequential mental processes that are commonly proposed.


McDonald, R.I., Newell, B.R., & Denson, T.F. (2014). Would you rule out going green? The effect of inclusion versus exclusion mindset on pro-environmental willingness. European Journal of Social Psychology, 44, 507-513  PDF
 ABSTRACT 

Two experiments demonstrate that participants’ willingness to endorse adopting pro-environmental behaviors is influenced substantially by a decision-framing effect: the inclusion–exclusion discrepancy. Participants were presented with a list of 26 pro-environmental behaviors (e.g., take a shorter shower, buy local produce). In both experiments, participants asked to cross out the behaviors they would not be willing to engage in (exclusion mindset) generated 30% larger consideration sets than those asked to circle behaviors that they would be willing to do (inclusion mindset). Experiment 2 identified qualities of the behaviors that accounted for the differences in the size of consideration sets, namely effort and opportunity. The results suggest the counter-intuitive notion that encouraging people to think about what they would not do for the environment might lead them to do more.




2013
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De Zilva, D., Mitchell, C.J., & Newell, B.R. (2013). Eliminating the mere exposure effect through changes in context between exposure and test. Cognition & Emotion, 27, 1345-1358  PDF
 ABSTRACT 

The present study examined the extent to which increased liking of exposed stimuli*the mere exposure effect*is dependent on experiencing the stimuli in the same context in exposure and on test. Participants were repeatedly exposed to pairs of cues (nonsense words) and target stimuli (faces and shapes), and were asked to rate the pleasantness of the target stimuli in a subsequent test phase. Familiar targets were preferred to novel targets*a mere exposure effect was obtained. This preference for familiar targets was disrupted, however, when the cuetarget pairings were rearranged between exposure and test, or a novel cue was introduced at test. Overall, the study suggests that the context of exposure and test moderates the mere exposure effect. Liking of stimuli due to exposure is specific to the context of exposure and does not apply to new or familiar but different contexts.


De Zilva, D., Vu, L., Newell, B.R., & Pearson, J. (2013). Exposure is not enough: Suppressing stimuli from awareness can abolish the mere exposure effect. PLOS One, 8(10): e77726.  PDF
 ABSTRACT 

Passive exposure to neutral stimuli increases subsequent liking of those stimuli – the mere exposure effect. Because of the broad implications for understanding and controlling human preferences, the role of conscious awareness in mere exposure has received much attention. Previous studies have claimed that the mere exposure effect can occur without conscious awareness of the stimuli. In two experiments, we applied a technique new to the mere exposure literature, called continuous flash suppression, to expose stimuli for a controlled duration with and without awareness. To ensure the reliability of the awareness manipulation, awareness was monitored on a trial-by-trial basis. Our results show that under these conditions the mere exposure effect does not occur without conscious awareness. In contrast, only when participants were aware of the stimuli did exposure increase liking and recognition. Together these data are consistent with the idea that the mere exposure effect requires conscious awareness and has important implications for theories of memory and affect.


Martire, K. A., Kemp R.I., Watkins I., Sayle, M., & Newell, B.R. (2013). The expression and interpretation of uncertain forensic science evidence: Verbal equivalence, evidence strength and the weak evidence effect. Law & Human Behavior, 37, 197-207  PDF 
 ABSTRACT 

Standards published by the Association of Forensic Science Providers (2009, Standards for the formulation of evaluative forensic science expert opinion, Science & Justice, Vol. 49, pp. 161–164) encourage forensic scientists to express their conclusions in the form of a likelihood ratio (LR), in which the value of the evidence is conveyed verbally or numerically. In this article, we report two experiments (using undergraduates and Mechanical Turk recruits) designed to investigate how much decision makers change their beliefs when presented with evidence in the form of verbal or numeric LRs. In Experiment 1 (N = 94), participants read a summary of a larceny trial containing inculpatory expert testimony in which evidence strength (low, moderate, high) and presentation method (verbal, numerical) varied. In Experiment 2 (N = 411), participants read the same larceny trial, this time including either exculpatory or inculpatory expert evidence that varied in strength (low, high) and presentation method (verbal, numerical). Both studies found a reasonable degree of correspondence in observed belief change resulting from verbal and numeric formats. However, belief change was considerably smaller than Bayesian calculations would predict. In addition, participants presented with evidence weakly supporting guilt tended to “invert” the evidence, thereby counterintuitively reducing their belief in the guilt of the accused. This “weak evidence effect” was most apparent in the verbal presentation conditions of both experiments, but only when the evidence was inculpatory. These findings raise questions about the interpretability of LRs by jurors and appear to support an expectancy-based account of the weak evidence effect.


Martire, K.A., Kemp, R.I., & Newell, B.R. (2013). The psychology of interpreting expert evaluative opinions. Australian Journal of Forensic Sciences, 45, 305-314  PDF 
 ABSTRACT 

The standards for expressions of evaluative opinions in the forensic sciences are increasingly being challenged and refined. Where once categorical statements regarding the origin of a trace were standard practice, criminalists are now being encouraged to represent the uncertainty associated with their inferential process by using numerical or verbal likelihood ratios. Although there are valid reasons to support this shift, the approach is not without limitations. Decades of psychological research investigating the interpretation and integration of probabilistic expressions, and the equivalence of verbal and numerical formulations for uncertainty, reveals a disconnect between what is intended by experts and what is understood by decisionmakers. In this paper we present an indicative review of the psychological evidence to foster communication and collaboration between forensic scientists and psychologists and reduce instances of miscommunication in our criminal justice system.


Guney, S., & Newell, B.R. (2013). Fairness overrides reputation: the importance of fairness considerations in altruistic cooperation. Frontiers in Human Neuroscience, 7, 252  PDF 
 ABSTRACT 

Behavioral findings in several strategic games indicate that people punish others if they think they are being treated unequally, even at the cost of minimizing their own material payoff. We investigated the primary driving force behind such non-self-regarding behavior, so-called, altruistic cooperation. In all of our studies, a mini ultimatum game was played either one-shot (in Experiment 1a and 1b) or repeatedly (Experiment 2), and rejections of inequitable distribution were taken as a measure of altruistic cooperation. In Experiment 1a, we replicated previous findings indicating that the key mechanism contributing to the emergence of altruistic cooperation is fairness considerations. In Experiment 1b, we delved into the relative importance of two aspects of fairness considerations (i.e., outcome fairness and intentions) and showed that both aspects were effective in determining the level of altruistic cooperation, with the contribution of intentions being more important. In Experiment 2, we investigated the effect of the opportunity for reputation building and future interaction on altruistic cooperation. We found that these factors became influential only when fairness considerations were weakened, particularly, as a result of the removal of the possible intentions behind an offer.


Newell, B.R., van Ravenzwaaij, D., & Donkin, C. (2013). A Quantum of Truth? Querying the Alternative Benchmark for Human Cognition. Behavioral and Brain Sciences (Commentary), 36, 300

Shanks, D.R., Newell, B.R., Lee, E.H., Balakrishnan, D., Ekelund, L., Cenac, Z., Kavvadia, F., & Moore, C.(2013). Priming Intelligent Behavior: An Elusive Phenomenon. PLoS One, 8(4): e56515  PDF 
 ABSTRACT 

Can behavior be unconsciously primed via the activation of attitudes, stereotypes, or other concepts? A number of studies have suggested that such priming effects can occur, and a prominent illustration is the claim that individuals’ accuracy in answering general knowledge questions can be influenced by activating intelligence-related concepts such as professor or soccer hooligan. In 9 experiments with 475 participants we employed the procedures used in these studies, as well as a number of variants of those procedures, in an attempt to obtain this intelligence priming effect. None of the experiments obtained the effect, although financial incentives did boost performance. A Bayesian analysis reveals considerable evidential support for the null hypothesis. The results conform to the pattern typically obtained in word priming experiments in which priming is very narrow in its generalization and unconscious (subliminal) influences, if they occur at all, are extremely shortlived. We encourage others to explore the circumstances in which this phenomenon might be obtained.


Camilleri, A.R,. & Newell, B.R. (2013). The long and short of it: Closing the description-experience "gap" by taking the long run view. Cognition, 126, 54-71  PDF  CORRIGENDUM 
 ABSTRACT 

Previous research has shown that many choice biases are attenuated when short-run decisions are reframed to the long run. However, this literature has been limited to descriptionbased choice tasks in which possible outcomes and their probabilities are explicitly specified. A recent literature has emerged showing that many core results found using the description paradigm do not generalize to experience-based choice tasks in which possible outcomes and their probabilities are learned from sequential sampling. In the current study, we investigated whether this description-experience choice gap occurs in the long run. We examined description- and experience-based preferences under two traditional short run framed choice tasks (single-play, repeated-play) and also a long-run frame (multi-play). We found a reduction in the size of the description-experience gap in the long-run frame, which was attributable to greater choice maximizing in the description format and reduced overweighting of rare events in the experience format. We interpret these results as a ‘‘broad bracketing’’ effect: the long-run mindset attenuates short-run biases such as loss aversion and reliance on small samples.


Camilleri, A.R., & Newell, B.R.(2013). Mind the gap? Description, experience, and the continuum of uncertainty in risky choice. Progress in Brain Research, 202, 55-71

Newell, B.R., Moore, C.P., Wills, A.J., & Milton, F. (2013). Reinstating the frontal lobes? Having more time to think improves "implicit" perceptual categorization. A comment on Filoteo, Lauritzen & Maddox, 2010. Psychological Science, 24, 386-389  PDF   SUPPLEMENTARY

Newell, B.R., Koehler, D.J., James, G., Rakow, T., & van Ravenzwaaij, D. (2013). Probability Matching in Risky Choice: The interplay of feedback and strategy availability. Memory & Cognition, 41, 329-338  PDF  
 ABSTRACT 

Probability matching in sequential decision making is a striking violation of rational choice that has been observed in hundreds of experiments. Recent studies have demonstrated that matching persists even in described tasks in which all the information required for identifying a superior alternative strategy—maximizing—is present before the first choice is made. These studies have also indicated that maximizing increases when (1)the asymmetry in the availability of matching and maximizing strategies is reduced and (2)normatively irrelevant outcome feedback is provided. In the two experiments reported here, we examined the joint influences of these factors, revealing that strategy availability and outcome feedback operate on different time courses. Both behavioral and modeling results showed that while availability of the maximizing strategy increases the choice of maximizing early during the task, feedback appears to act more slowly to erode misconceptions about the task and to reinforce optimal responding. The results illuminate the interplay between “topdown” identification of choice strategies and “bottom-up” discovery of those strategies via feedback.



2012
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Dunn, J.C., Newell, B.R., & Kalish, M. (2012). The effect of feedback delay and feedback type on perceptual category learning: The limits of multiple systems. Journal of Experimental Psychology: Learning, Memory, & Cognition, 38, 840-859  PDF 
 ABSTRACT 

Evidence that learning rule-based (RB) and information-integration (II) category structures can be dissociated across different experimental variables has been used to support the view that such learning is supported by multiple learning systems. Across 4 experiments, we examined the effects of 2 variables, the delay between response and feedback and the informativeness of feedback, which had previously been shown to dissociate learning of the 2 types of category structure. Our aim was twofold: first, to determine whether these dissociations meet the more stringent inferential criteria of state-trace analysis and, second, to determine the conditions under which they can be observed. Experiment 1 confirmed that a mask-filled feedback delay dissociated the learning of RB and II category structures with minimally informative (yes/no) feedback and also met the state-trace criteria for the involvement of multiple latent variables. Experiment 2 showed that this effect is eliminated when a less similar, fixed pattern mask is presented in the interval between response and feedback. Experiment 3 showed that the selective effect of feedback delay on II learning is reduced with fully informative feedback (in which the correct category is specified after an incorrect response) and that feedback type did not dissociate RB and II learning. Experiment 4 extended the results of Experiment 2, showing that the differential effect of feedback delay is eliminated when a fixed pattern mask is used. These results pose important challenges to models of category learning, and we discuss their implications for multiple learning system models and their alternatives.


Lewandowsky, S., Yang, L-X., Newell, B.R., & Kalish, M.(2012). Working Memory Does Not Dissociate Between Different Perceptual Categorization Tasks. Journal of Experimental Psychology: Learning, Memory, & Cognition, 38, 881-904  PDF 
 ABSTRACT 

Working memory is crucial for many higher level cognitive functions, ranging from mental arithmetic to reasoning and problem solving. Likewise, the ability to learn and categorize novel concepts forms an indispensable part of human cognition. However, very little is known about the relationship between working memory and categorization. This article reports 2 studies that related people’s working memory capacity (WMC) to their learning performance on multiple rule-based and information-integration perceptual categorization tasks. In both studies, structural equation modeling revealed a strong relationship between WMC and category learning irrespective of the requirement to integrate information across multiple perceptual dimensions. WMC was also uniformly related to people’s ability to focus on the most task-appropriate strategy, regardless of whether or not that strategy involved information integration. Contrary to the predictions of the multiple systems view of categorization, working memory thus appears to underpin performance in both major classes of perceptual category-learning tasks.


Griffiths, O., Hayes, B.K., & Newell, B.R. (2012). Feature-based versus category-based induction with uncertain categories. Journal of Experimental Psychology: Learning, Memory, & Cognition, 38, 576-595  PDF 
 ABSTRACT 

Previous research has suggested that when feature inferences have to be made about an instance whose category membership is uncertain, feature-based inductive reasoning is used to the exclusion of categorybased induction. These results contrast with the observation that people can and do use category-based induction when category membership is known. The present experiments examined the conditions that drive feature-based and category-based strategies in induction under category uncertainty. Specifically, 2 experiments investigated whether reliance on feature-based inductive strategies is a product of the lack of coherence in the categories used in previous research or is due to the use of a decision-only induction procedure. Experiment 1 found that feature-based reasoning remained the preferred strategy even when categories with relatively high internal coherence were used. Experiment 2 found a shift toward category-based reasoning when participants were trained to classify category members prior to feature induction. Together, these results suggest that an appropriate conceptual representation must be formed through experience with a category before it is likely to be used as a basis for feature induction.


Newell, B.R. (2012). Levels of Explanation in Category Learning. Australian Journal of Psychology, 64, 46-61  PDF 
 ABSTRACT 

Multiple-system accounts of category learning are now entrenched in the cognitive neuroscience literature. This entrenchment sometimes seems impervious to behavioural evidence that contradicts or questions key assumptions of multiple-systems accounts. In this brief article, I consider relevant sources of evidence (behavioural, neuropsychological, neuro-imaging) and argue that the evidence from all sources is not as clear-cut as many multiple-system theorists often claim. More importantly, the review emphasises that one needs to be sensitive to the desired level of explanation of category learning (psychological, biological, mathematical) when considering the relevance of different types of data and the adequacy of proposed accounts.


Guney, S., & Newell, B.R. (2012). Is strong reciprocity really strong in the lab let alone the real world? Behavioral and Brain Sciences (Commentary), 35, 29

2011
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Griffiths, O., Hayes, B. K., Newell, B.R., & Papadopoulos, C. (2011). Where to look first for explanation of induction with uncertain categories Psychonomic Bulletin & Review, 18, 1212-1221  PDF 
 ABSTRACT 

Recent research has examined how people predict unobserved features of an object when its category membership is ambiguous. The debate has focused on whether predictions are based solely on information from the most likely category, or whether information from other possible categories is also used. In the present experiment, we compared these category-based approaches with feature conjunction reasoning, where predictions are based on a comparison among exemplars (rather than categories) that share features with a target object. Reasoning strategies were assessed by examining patterns of feature prediction and by using an eye gaze measure of attention during induction. The main findings were (1) the majority of participants used feature conjunction rather than categorical strategies, (2) people predominantly gazed at the exemplars that were most similar to the target object, and (3) although people gazed most at the most probable category to which an object could belong, they also attended to other plausible category alternatives during induction. These findings question the extent to which category-based reasoning is used for induction when category membership is uncertain.


Lee, M.D., & Newell, B.R. (2011). Using hierarchical Bayesian methods to examine the tools of decision making. Judgment and Decision Making, 6, 832-842  PDF 
 ABSTRACT 

Hierarchical Bayesian methods offer a principled and comprehensive way to relate psychological models to data. Here we use them to model the patterns of information search, stopping and deciding in a simulated binary comparison judgment task. The simulation involves 20 subjects making 100 forced choice comparisons about the relative magnitudes of two objects (which of two German cities has more inhabitants). Two worked-examples show how hierarchical models can be developed to account for and explain the diversity of both search and stopping rules seen across the simulated individuals. We discuss how the results provide insight into current debates in the literature on heuristic decision making and argue that they demonstrate the power and flexibility of hierarchical Bayesian methods in modeling human decisionmaking.


Newell, B.R., & Rakow, T. (2011). Revising beliefs about the merits of unconscious thought: Evidence in favor of the null hypothesis. Social Cogniton, 29, 711-726  PDF 
 ABSTRACT 

Claims that a period of distraction—designed to promote unconscious thought—improves decisions relative to a period of conscious deliberation are as multifarious as they are controversial. We reviewed 16 experimental studies from two labs, across a range of tasks (multi-attribute choice, creativity, moral dilemmas), only one of which found any significant advantages for unconscious thought. The results of each study were analyzed using Bayesian t tests. Unlike traditional significance tests, these tests allow an assessment of the evidence for the null hypothesis—in this case, no difference between conscious and unconscious thought. This is done by computing the likelihood ratio (or Bayes factor), which compares the probability of the data given the null against the probability of the data given a distribution of plausible alternate hypotheses. Almost without exception, the probability of the data given the null exceeded that for the alternate distribution. A Bayesian t test for the average effect size across all studies (N= 1,071) yielded a Bayes factor of 9, which can be taken as clear evidence supporting the null hypothesis; that is, a period of distraction had no noticeable improving effect on the range of decision-making tasks in our sample.


Newell, B.R., & Lee, M.D. (2011). The right tool for the job? Comparing an Evidence Accumulation and a Naïve Strategy Selection Model of Decision Making. Journal of Behavioral Decision Making, 24, 456-481  PDF 
 ABSTRACT 

Analyses of multi-attribute decision problems are dominated by accounts which assume people select from a repertoire of cognitive strategies to make decisions. This paper explores an alternative account based on sequential sampling and evidence accumulation. Two experiments varied aspects of a decision environment to examine competing models of decision behavior. The results highlighted the intra-participant consistency but inter-participant differences in the amount of evidence considered in decisions. This pattern was best captured by a sequential evidence accumulation model (SEQ) which treated pure Take-The-Best (TTB) and pure ‘‘rational’’ (RAT) models as special cases of a single model. The SEQ model was also preferred by the minimum description length (MDL) criterion to a naive strategy-selection model (NSS) which assumed that TTB or RAT could be selected with some probability for each decision.


Hayes, B.K., & Newell, B.R. (2011). The uncertain status of Bayesian accounts of reasoning. Behavioral and Brain Sciences (Commentary), 34, 201-202

Newell, B.R. (2011). Recognising the recognition heuristic for what is (and what it's not). Judgment and Decision Making, 6, 409-412  PDF 
 ABSTRACT 

The diversity, ingenuity and differences of opinion displayed in the articles of the recent special issues on the recognition heuristic are testament to the power and theoretical fertility of a simple idea about the role of recognition in decision making. In this brief comment I mention a number of these papers, but my focus is on points of agreement and disagreement with the conclusions drawn by Gigerenzer and Goldstein (2011) in their review of a decade’s worth of research on the recognition heuristic.


Camilleri, A.R., & Newell, B.R. (2011). When and why rare events are underweighted: A direct comparison of the sampling, partial feedback, full feedback and description choice paradigms. Psychonomic Bulletin & Review, 18, 377-384  PDF 
 ABSTRACT 

Two paradigms are commonly used to examine risky choice based on experiential sampling. The feedback paradigm involves a large number of repeated, consequential choices with feedback about the chosen (partial feedback) or chosen and foregone (full feedback) payoffs. The sampling paradigm invites cost-free samples before a single consequential choice. Despite procedural differences, choices in both experience-based paradigms suggest underweighting of rare events relative to their objective probability. This contrasts with overweighting when choice options are described, thereby leading to a ‘gap’ between experience and description-based choice. Behavioural data and modelbased analysis from an experiment comparing choices from description, sampling, and partial- and full-feedback paradigms replicated the ‘gap’, but also indicated significant differences between feedback and sampling paradigms. Our results suggest that mere sequential experience of outcomes is insufficient to produce reliable underweighting. We discuss when and why underweighting occurs, and implicate repeated, consequential choice as the critical factor.


Camilleri, A.R., & Newell, B.R. (2011). Description- and Experience-based Choice: Does Equivalent Information Equal Equivalent Choice? Acta Psychologica, 136, 276-284  PDF 
 ABSTRACT 

Does the manner in which people acquire information affect their choices? Recent research has contrasted choices based on summary descriptions (e.g. a 100% chance of $3 vs. an 80% chance of $4) with those based on the ‘experience’ of drawing samples from environments that do (or should) match those provided by descriptions. Intriguingly, decision-makers' preferences differ markedly across the two formats: the so-called description–experience “gap” — but debate over the cause of this gap continues. We employed novel techniques to ensure strict control over both external and internal biases in the samples of information that people used to make decisions from experience. In line with some other recent research, we found a much diminished gap in both experiments suggesting that the divergence in choices based on description and sequentially acquired (non-consequential) samples is largely the result of non-equivalent information at the point of choice. The implications for models of risky choice are discussed.


Newell, B.R., Dunn, J.C., & Kalish, M. (2011). Systems of category learning: Fact or fantasy? In B.H. Ross (Ed) The Psychology of Learning & Motivation, Vol 54, 167-215  PDF 
 ABSTRACT 

Psychology abounds with vigorous debates about the need for one or more underlying mental processes or systems to explain empirical observations. The field of category learning provides an excellent exemplar. We present a critical examination of this field focusing on empirical, methodological, and mathematical modeling considerations. We review what is often presented as the “best evidence” for multiple systems of category learning and critique the evidence by considering three questions: (1) Are multiple-systems accounts the only viable explanations for reported effects? (2) Are the inferences sound logically and methodologically? (3) Are the mathematical models that can account for behavior sufficiently constrained, and are alternative (single-system) models applicable? We conclude that the evidence for multiple-systems accounts of category learning does not withstand such scrutiny. We end by discussing the varieties of explanation that can be offered for psychological phenomena and highlight why multiple-systems accounts often provide an illusory sense of scientific progress.


Hayes, B.K., Kurniawan, H., & Newell, B.R. (2011). Rich in vitamin C or just a convenient snack? Multiple-category reasoning with cross-classified foods. Memory & Cognition, 39, 92-106  PDF 
 ABSTRACT 

Two studies examined multiple category reasoning in property induction with cross-classified foods. Pilot tests identified foods that were more typical of a taxonomic category (e.g., “fruit”; termed ‘taxonomic primary’) or a script based category (e.g., “snack foods”; termed ‘script primary’). They also confirmed that taxonomic categories were perceived as more coherent than script categories. In Experiment 1 participants completed an induction task in which information from multiple categories could be searched and combined to generate a property prediction about a target food. Multiple categories were more often consulted and used in prediction for script primary than for taxonomic primary foods. Experiment 2 replicated this finding across a range of property types but found that multiple category reasoning was reduced in the presence of a concurrent cognitive load. Property type affected which categories were consulted first and how information from multiple categories was weighted. The results show that multiple categories are more likely to be used for property predictions about cross-classified objects when an object is primarily associated with a category that has low coherence.


Papadopoulos, C., Hayes, B.K., & Newell, B.R. (2011). Non-categorical approaches to feature prediction with uncertain categories. Memory & Cognition, 39, 304-318  PDF 
 ABSTRACT 

In four experiments, we investigated how people make feature predictions about objects whose category membership is uncertain. Artificial visual categories were presented and remained in view while a novel instance with a known feature, but uncertain category membership was presented. All four experiments showed that feature predictions about the test instance were most often based on feature correlations (referred to as feature conjunction reasoning). Experiment 1 showed that feature conjunction reasoning was generally preferred to category-based induction in a feature prediction task. Experiment 2 showed that people used all available exemplars to make feature conjunction predictions. Experiments 3 and 4 showed that the preference for predictions based on feature conjunction persisted even when category-level information was made more salient and inferences involving a larger number of categories were required. Little evidence of reasoning based on the consideration of multiple categories (e.g., Anderson, (Psychological Review, 98:409–429, 1991)) or the single, most probable category (e.g., Murphy & Ross, (Cognitive Psychology, 27:148–193, 1994)) was found.



2010
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Newell, B.R., Paton, H., Hayes, B.K., & Griffiths, O. (2010). Speeded induction under uncertainty: The influence of multiple categories and feature conjunctions. Psychonomic Bulletin & Review, 17, 869-874  PDF 
 ABSTRACT 

When people are uncertain about the category membership of an item (e.g., Is it a dog or a dingo?), research shows that they tend to rely only on the dominant or most likely category when making inductions (e.g., How likely is it to befriend me?). An exception has been reported using speeded induction judgments where participants appeared to use information from multiple categories to make inductions (Verde, Murphy, & Ross, 2005). In two speeded induction studies, we found that participants tended to rely on the frequency with which features co-occurred when making feature predictions, independently of category membership. This pattern held whether categories were considered implicitly (Experiment 1) or explicitly (Experiment 2) prior to feature induction. The results converge with other recent work suggesting that people often rely on feature conjunction information, rather than category boundaries, when making inductions under uncertainty.


Vojdanoska, M., Cranney, J. & Newell, B.R. (2010). The testing effect: The role of feedback and collaboration in a tertiary classroom setting. Applied Cognitive Psychology, 24, 1183-1195  PDF 
 ABSTRACT 

Successful retrieval on a test compared to just re-studying material improves long-term retention—a phenomenon called the ‘testing effect’. This study investigated the role of feedback and collaborative testing on the retention of course material in a tertiary educational setting. Tested material was better retained relative to non-tested material (testing effect), and feedback facilitated correction of errors. Group testing produced higher performance on the initial, but not final test performance, compared to individual testing. This set of findings suggests that to encourage long-term retention, educators should utilise individual formative testing with feedback; theoretical implications are also discussed.


Newell, B.R., & Pitman, A.J. (2010). The psychology of global warming: Improving the fit between the science and the message. Bulletin of the American Meteorological Society, 91, 1003-1014  PDF 
 ABSTRACT 

Consider the following question: If a bat and a ball cost $1.10 in total and the bat costs $1 more than the ball, how much does the ball cost? If you are like many people, your immediate answer would be 10¢ (Kahneman and Frederick 2002). You would be wrong. Think a little and you will see why. This is a simple question and the answer is easy, but people still often get it wrong. Contrast the simplicity of this question with the complexity of global warming. Is there any hope of communicating such complex issues if many people fall foul on a simple mental arithmetic problem? Yes. These simple examples and the resulting errors can illuminate how we make decisions. Knowledge of these mechanisms can help us understand how to communicate climate science to fit with the way humans process information. Our aim in this paper is to provide some suggestions for improving this fit.


Bröder, A., Newell, B.R., & Platzer, C. (2010). Cue integration vs exemplar-based reasoning in multi-attribute decisions from memory: A matter of cue representation. Judgment and Decision Making, 5, 326-338  PDF 
 ABSTRACT 

Inferences about target variables can be achieved by deliberate integration of probabilistic cues or by retrieving similar cue-patterns (exemplars) from memory. In tasks with cue information presented in on-screen displays, rule-based strategies tend to dominate unless the abstraction of cue-target relations is unfeasible. This dominance has also been demonstrated — surprisingly — in experiments that demanded the retrieval of cue values from memory (M. Persson & J. Rieskamp, 2009). In three modified replications involving a fictitious disease, binary cue values were represented either by alternative symptoms (e.g., fever vs. hypothermia) or by symptom presence vs. absence (e.g., fever vs. no fever). The former representation might hinder cue abstraction. The cues were predictive of the severity of the disease, and participants had to infer in each trial who of two patients was sicker. Both experiments replicated the rule-dominance with present-absent cues but yielded higher percentages of exemplar-based strategies with alternative cues. The experiments demonstrate that a change in cue representation may induce a dramatic shift from rule-based to exemplar-based reasoning in formally identical tasks.


Rakow, T., Newell, B.R., & Zougkou, K. (2010). The role of working memory in information acquisition and decision making: Lessons from the binary prediction task. The Quarterly Journal of Experimental Psychology, 63, 1335-1360  PDF 
 ABSTRACT 

The effects of memory constraints upon information acquisition and decision making were examined in two experiments using binary prediction tasks, where participants observe outcomes for two options before deciding which one to bet upon. Our studies extend previous investigations to the case where participants learn the structure of the task through observation, but where information acquisition is separated from the task of prediction. Participants with higher cognitive capacity (larger memory span or higher intelligence) were more likely to adopt the “maximizing” strategy (always selecting the more frequent alternative). This finding conflicts with some recent investigations of similar tasks, a contrast that implies that the presence of feedback on choices may be important in determining the strategic actions of high-capacity individuals. Participants selecting the optimal strategy were in turn more efficient in their data acquisition. The behaviour of participants adopting suboptimal choice strategies was consistent with prediction based upon a “narrow window of experience”—that is, seeking to match the characteristics of small samples of observations.


Newell, B.R., Dunn, J.C., & Kalish, M. (2010). The dimensionality of perceptual category learning: A state-trace analysis. Memory & Cognition, 38, 563-581  PDF 
 ABSTRACT 

State-trace analysis was used to investigate the effect of concurrent working memory load on perceptual category learning. Initial reanalysis of Zeithamova and Maddox (2006, Experiment 1) revealed an apparently two-dimensional state-trace plot consistent with a dual-system interpretation of category learning. However, three modified replications of the original experiment found evidence of a single resource underlying the learning of both rule-based and information integration category structures. Follow-up analyses of the Zeithamova and Maddox data, restricted to only those participants who had learned the category task and performed the concurrent working memory task adequately, revealed a one-dimensional plot consistent with a single-resource interpretation and the results of the three new experiments. The results highlight the potential of state-trace analysis in furthering our understanding of the mechanisms underlying category learning.


Bonner, C., & Newell, B.R. (2010). In conflict with ourselves? An investigation of heuristic and analytic processes in decision making. Memory & Cognition, 38, 186-196  PDF 
 ABSTRACT 

Many theorists propose two types of processing: heuristic and analytic. In conflict tasks, in which these processing types lead to opposing responses, giving the analytic response may require both detection and resolution of the conflict. The ratio bias task, in which people tend to treat larger numbered ratios (e.g., 20/100) as indicating a higher likelihood of winning than do equivalent smaller numbered ratios (e.g., 2/10), is considered to induce such a conflict. Experiment 1 showed response time differences associated with conflict detection, resolution, and the amount of conflict induced. The conflict detection and resolution effects were replicated in Experiment 2 and were not affected by decreasing the influence of the heuristic response or decreasing the capacity to make the analytic response. The results are consistent with dual-process accounts, but a single-process account in which quantitative, rather than qualitative, differences in processing are assumed fares equally well in explaining the data.


Rakow, T., & Newell, B.R. (2010). Degrees of uncertainty: An overview and framework for future research on experience-based choice. Journal of Behavioral Decision Making, 23, 1-14  PDF 
 ABSTRACT 

A striking finding has emerged recently in the literature: When decision makers are faced with essentially the same choice, their preferences differ as a function of whether options are described or are ‘‘experienced’’ via observation and feedback. For example, when presented the described choice: (A) A 90% chance of $0 and a 10% chance of $10 or (B) $1 for sure, people tend to prefer (A). But when those same two options are experienced through observation of ‘‘draws’’ from two payoff distributions that match the described options, the modal preference reverses. Why? This is just one question that the papers in this special issue address. In addition, they address the rich repertoire of issues that arise when one considers experience-based choices. The decisions-from experience paradigm—with its focus on the acquisition and integration of information prior to choice, as well the choice itself—taps many of the fundamentals of psychology (learning, memory, encoding, knowledge representation, modelling) thus inspiring novel and fruitful avenues for research. This paper reviews recent research on experience-based choice, and highlights the contribution of the papers in the special issue. The paper introduces a framework that places different types of decisions along a continuum of uncertainty about what one is choosing between, which emphasizes the rich and varied role of ‘‘experience’’ in decision making. It ends by identifying important unsolved questions that are ripe for future research.



2009
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Camilleri, A.R., & Newell, B.R. (2009). The role of representation in experience-based choice. Judgment and Decision Making, 4, 518-529  PDF 
 ABSTRACT 

Recently it has been observed that different choices can be made about structurally identical risky decisions depending on whether information about outcomes and their probabilities is learned by description or from experience. Current evidence is equivocal with respect to whether this choice “gap” is entirely an artefact of biased samples. The current experiment investigates whether a representational bias exists at the point of encoding by examining choice in light of decision makers’ mental representations of the alternatives, measured with both verbal and nonverbal judgment probes. We found that, when estimates were gauged by the nonverbal probe, participants presented with information in description format (as opposed to experience) had a greater tendency to overestimate rare events and underestimate common events. The choice gap, however, remained even when accounting for this judgment distortion and the effects of sampling bias. Indeed, participants’ estimation of the outcome distribution did not mediate their subsequent choice. It appears that experience-based choices may derive from a process that does not explicitly use probability information.


Li, S.Y.W., Rakow, T.R. & Newell, B.R.(2009). Personal experience in doctor and patient decision making: From psychology to medicine. Journal of Evaluation in Clinical Practice, 15, 993-995  PDF 
 ABSTRACT 

Traditional decision research shows that when people are told the probability of a rare event (e.g. the chance of side effects), they generally treat this event as if it were more likely than its objective probability (overweighting). In contrast, recent studies indicate that when outcomes are experienced firsthand, people tend to underweight the probability of rare events. In this paper, we suggest that the distinction between described and experienced information can play a significant role in shared decision making, and can provide a plausible explanation for some discrepancies between the perspectives of doctors and patients. We highlight some of the advantages and disadvantages of experiential and description-based information, and how knowledge of these might be used to improve risk communication.


Hayes, B.K. & Newell, B.R.(2009). Induction with uncertain categories: When do people consider the alternative categories? Memory & Cognition, 37, 730-743  PDF 
 ABSTRACT 

These three experiments examined how people make property inferences about exemplars whose category membership is uncertain. Participants were shown two categories and a novel exemplar with a feature that indicated that the exemplar was more likely to belong to one category (target) than to the other (nontarget). Participants then made categorization decisions and property inferences about the novel exemplar. In some conditions, property inferences could be made only by considering both target and nontarget categories. In other conditions, predictions could be based on both categories or on the target category alone. Consistent with previous studies (e.g., Murphy & Ross, 1994, 2005), we found that many people made predictions based only on consideration of the target category. However, the prevalence of such single-category reasoning was greatly reduced by highlighting the costs of neglecting nontarget alternatives and by asking for inferences before categorization decisions. The results suggest that previous work may have exaggerated the prevalence of single-category reasoning and that people may be more flexible in their use of multiple categories in property inference than has been previously recognized.


Newell, B.R., Mitchell, C.J., & Hayes, B.K.(2009). Missing the target: A reply to Koehler & Macchi (2009). Journal of Behavioral Decision Making, 22, 528-532  PDF 
 ABSTRACT 

Koehler and Macchi (2009) criticize the experiments presented in Newell, Mitchell, and Hayes (2008) as being ‘‘virtually irrelevant’’ to exemplar cuing theory. This reply addresses that interpretation and argues that the experiments dealt with issues at the heart of the theory and provided evidence highly relevant to understand how people think about low-probability events. The role of the ‘target’ in probabilistic statements is examined, highlighting the need for further theoretical and empirical clarification of the concept. The remaining specific criticisms raised in the commentary are discussed as well.


Newell, B.R. (2009). What is the link between propositions and memories? Behavioural and Brain Sciences, 32, 219 (Commentary)  PDF 
 ABSTRACT 

Mitchell et al. present a lucid and provocative challenge to the claim that links between mental representations are formed automatically. However, the propositional approach they offer requires clearer specification, especially with regard to how propositions and memories interact. A definition of a system would also clarify the debate, as might an alternative technique for assessing task “dissociations.”


Newell, B.R., Weston, N.J., Tunney, R.J., & Shanks, D.R. (2009). The effectiveness of feedback in multiple-cue probability learning. The Quarterly Journal of Experimental Psychology, 62, 890-908  PDF 
 ABSTRACT 

How effective are different types of feedback in helping us to learn multiple contingencies? This article attempts to resolve a paradox whereby, in comparison to simple outcome feedback, additional feedback either fails to enhance or is actually detrimental to performance in nonmetric multiple-cue probability learning (MCPL), while in contrast the majority of studies of metric MCPL reveal improvements at least with some forms of feedback. In three experiments we demonstrate that if feedback assists participants to infer cue polarity then it can in fact be effective in nonmetric MCPL. Participants appeared to use cue polarity information to adopt a linear judgement strategy, even though the environment was nonlinear. The results reconcile the paradoxical contrast between metric and nonmetric MCPL and support previous findings of people’s tendency to assume linearity and additivity in probabilistic cue learning.


Newell, B.R., Wong, K.Y., Cheung, C.H.J., & Rakow, T. (2009). Think, blink or sleep on it? The impact of modes of thought on complex decision making. The Quarterly Journal of Experimental Psychology, 62, 707-732  PDF 
 ABSTRACT 

This paper examines controversial claims about the merit of “unconscious thought” for making complex decisions. In four experiments, participants were presented with complex decisions and were asked to choose the best option immediately, after a period of conscious deliberation, or after a period of distraction (said to encourage “unconscious thought processes”). In all experiments the majority of participants chose the option predicted by their own subjective attribute weighting scores, regardless of the mode of thought employed. There was little evidence for the superiority of choices made “unconsciously”, but some evidence that conscious deliberation can lead to better choices. The final experiment suggested that the task is best conceptualized as one involving “online judgement” rather than one in which decisions are made after periods of deliberation or distraction. The results suggest that we should be cautious in accepting the advice to “stop thinking” about complex decisions.



2008
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Newell, B.R., & Dunn, J.C. (2008). Dimensions in data: Testing psychological models using state-trace analysis. Trends in Cognitive Sciences, 12, 285-290  PDF 
 ABSTRACT 

Cognitive science is replete with fertile and forceful debates about the need for one or more underlying mental processes or systems to explain empirical observations. Such debates can be found in many areas, including learning, memory, categorization, reasoning and decision-making. Multiple-process models are often advanced on the basis of dissociations in data. We argue and illustrate that using dissociation logic to draw conclusions about the dimensionality of data is flawed. We propose that a more widespread adoption of ‘state-trace analysis’ – an approach that overcomes these flaws – could lead to a re-evaluation of the need for multipleprocess models and to a re-appraisal of how these models should be formulated and tested.


Bonner, C. & Newell, B.R. (2008). How to make a risk seem riskier: The ratio bias versus construal level theory. Judgment and Decision Making, 3, 411-416  PDF 
 ABSTRACT 

Which statement conveys greater risk: “100 people die from cancer every day” or “36,500 people die from cancer every year”? In statistics where both frequencies and temporal information are used to convey risk, two theories predict opposite answers to this question. Construal level theory predicts that “100 people die from cancer every day” will be judged as more risky, while the ratio bias predicts that the equivalent “36,500 people die from cancer every year” will result in higher risk judgments. An experiment investigated which format produces higher risk ratings, and whether ratings are influenced by increasing the salience of the numerical or temporal part of the statistic. Forty-eight participants were randomly assigned to a numerical, temporal or control salience condition, and rated risk framed as number of deaths per day or per year. The year format was found to result in higher perceived risk, indicating that the ratio bias effect is dominant, but there was no effect of salience.


Rakow, T.R., Demes, K., & Newell, B.R. (2008). Biased samples not mode of presentation: Re-examining the apparent underweighting of rare events in experience-based choice. Organizational Behavior and Human Decision Processes, 106, 168-179  PDF 
 ABSTRACT 

Most experimental investigations of risky choice provide participants with a description of the probabilities and outcomes for each option, and observe that small probabilities are overweighted. However, when payoffs are learned from repeated experience of outcomes (as in many real-world decisions), different patterns of choice are observed—consistent with underweighting rare events. We re-examined this phenomenon to determine whether biased sampling and recency effects in experience-based choice could account for this description–experience gap. Two hundred and forty paid participants made choices for 12 pairs of simple gambles. In the objective description condition, probabilities and outcomes were specified. In the free sampling condition, participants observed repeated plays of each gamble before choosing. Participants in four yoked conditions received the same information as the free sampling participants—either described or experienced. Differences between objective description and free sampling were consistent with underweighting rare events in experience-based choice. However, consistent with a biased sampling account, patterns of choice in the yoked conditions barely differed from the free sampling condition: given identical information, presentation mode has no effect. Recency effects in choice occurred only when outcomes were actively sampled, and were unaffected by working memory capacity. The absence of recency for passive observation implies actor–observer differences in forming expectations or testing hypotheses. The results provide no support for the claim that decisions from description and decisions from experience require separate descriptive theories.


Newell, B.R., Cavenett, T., & Andrews, S. (2008). On the immunity of perceptual implicit memory to manipulations of attention. Memory & Cognition, 36, 725-734  PDF 
 ABSTRACT 

In four experiments, we examined the effect of manipulating study phase attention in a Stroop task on the extent of repetition priming in the lexical decision task (LDT). Experiment 1 replicated the immunity of the LDT to division of attention reported by Szymanski and MacLeod (1996), using a standard Stroop configuration. Response times to previously encountered words were identical regardless of whether the participants were required to read the words or name the color in which they were presented. Experiment 2 demonstrated that implementing the Stroop manipulation across separate visual objects reduced but did not eliminate priming of unattended words, provided the words remained in the attended region of the stimulus display. When this constraint was removed in Experiment 3, priming of unattended words disappeared. Experiment 4 demonstrated statistically equivalent priming for attended and unattended words when the Stroop manipulation remained in the same visual object but attention was directed to a single letter of the word. In all four experiments, the Stroop manipulation had a clear effect on recognition. These results qualify claims that the LDT might be immune to manipulations of study phase attention and suggest that the LDT has a lower threshold level of attention at encoding than do other standard implicit tests of memory.


Newell, B.R., Mitchell. C.J., & Hayes, B.K. (2008). Getting scarred and winning lotteries: Effects of exemplar cuing and statistical format on imagining low-probability events. Journal of Behavioral Decision Making, 21, 317-335  PDF 
 ABSTRACT 

Three experiments tested the exemplar cuing and frequency format accounts of how the ‘imaginability’ of low-probability events is enhanced. The experiments manipulated imaginability by varying the statistics used to describe negative (e.g. being scarred as a result of laser surgery) and positive (e.g. winning a lottery) low-probability events. The results strongly supported the frequency format account, whereby imaginability is enhanced through the use of frequency formats for conveying statistical information (e.g. 20 out of 2000 as opposed to 0.01%). However, only limited support was found for exemplar cuing (EC) theory. Overall the results support the claim that the imaginability of outcomes plays a key role in thinking about low-probability events, but question the mechanisms specified by EC theory for mediating such effects.


Newell, B.R. & Bröder, A. (2008). Cognitive processes, models and metaphors in decision research. Judgment and Decision Making, 3, 195-204  PDF 
 ABSTRACT 

Decision research in psychology has traditionally been influenced by the homo oeconomicus metaphor with its emphasis on normative models and deviations from the predictions of those models. In contrast, the principal metaphor of cognitive psychology conceptualizes humans as ‘information processors’, employing processes of perception, memory, categorization, problem solving and so on. Many of the processes described in cognitive theories are similar to those involved in decision making, and thus increasing cross-fertilization between the two areas is an important endeavour. A wide range of models and metaphors has been proposed to explain and describe ‘information processing’ and many models have been applied to decision making in ingenious ways. This special issue encourages cross-fertilization between cognitive psychology and decision research by providing an overview of current perspectives in one area that continues to highlight the benefits of the synergistic approach: cognitive modeling of multi-attribute decision making. In this introduction we discuss aspects of the cognitive system that need to be considered when modeling multi-attribute decision making (e.g., automatic versus controlled processing, learning and memory constraints, metacognition) and illustrate how such aspects are incorporated into the approaches proposed by contributors to the special issue. We end by discussing the challenges posed by the contrasting and sometimes incompatible assumptions of the models and metaphors.


Bröder, A. & Newell, B.R. (2008). Challenging some common beliefs: Empirical work within the adaptive toolbox. Judgment and Decision Making, 3, 205-214  PDF 
 ABSTRACT 

The authors review their own empirical work inspired by the adaptive toolbox metaphor. The review examines factors influencing strategy selection and execution in multi-attribute inference tasks (e.g., information costs, time pressure, memory retrieval, dynamic environments, stimulus formats, intelligence). An emergent theme is the re-evaluation of contingency model claims about the elevated cognitive costs of compensatory in comparison with non-compensatory strategies. Contrary to common assertions about the impact of cognitive complexity, the empirical data suggest that manipulated variables exert their influence at the meta-level of deciding how to decide (i.e., which strategy to select) rather than at the level of strategy execution. An alternative conceptualisation of strategy selection, namely threshold adjustment in an evidence accumulation model, is also discussed and the difficulty in distinguishing empirically between these metaphors is acknowledged.



2007
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Newell, B.R. & Hayes, B.K. (2007). Naturally nested, but why dual-process? Behavioural and Brain Sciences, 30, 276-277 (Commentary)

Newell, B.R. & Rakow, T. (2007). The role of experience in decisions from description. Psychonomic Bulletin & Review, 14, 1133-1139  PDF 
 ABSTRACT 

We extend research on the distinction between decisions from experience or description to situations in which people are given perfect information about outcome probabilities and have experience in an environment which matches the described information. Participants read a description of a die with more sides of one color than another (e.g., 4 black and 2 white sides) and were then asked either to predict the outcomes of rolls of the die or to select the best strategy for betting on the most likely outcome for each roll in a hypothetical game. Experience in the environment (trials), contingency (probability of the more likely alternative), and outcome feedback all had significant effects on the adoption of the optimal strategy (always predicting the most likely outcome), despite their normative irrelevance. Comparisons of experience with description-only conditions suggested that experience exerted an influence on performance if it was active—making predictions—but not if it was passive—observing outcomes. Experience had a negative initial impact on optimal responding: participants in description-only conditions selected the optimal strategy more often than those with 60 trials of prediction experience, a finding that reflects the seduction of “representative” responding.


Newell, B.R., Lagnado, D.A., & Shanks, D.R. (2007). Challenging the role of implicit processes in probabilistic category learning. Psychonomic Bulletin & Review, 14, 505-51  PDF 
 ABSTRACT 

Considerable interest in the hypothesis that different cognitive tasks recruit qualitatively distinct processing systems has led to the proposal of separate explicit (declarative) and implicit (procedural) systems. A popular probabilistic category learning task known as the weather prediction task is said to be ideally suited to examine this distinction because its two versions, “observation” and “feedback,” are claimed to recruit the declarative and procedural systems, respectively. In two experiments, we found results that were inconsistent with this interpretation. In Experiment 1, a concurrent memory task had a detrimental effect on the implicit (feedback) version of the task. In Experiment 2, participants displayed comparable and accurate insight into the task and their judgment processes in the feedback and observation versions. These findings have important implications for the study of probabilistic category learning in both normal and patient populations.


Newell, B.R., & Shanks, D.R. (2007). Recognizing what you like: examining the relation between the mere-exposure effect and recognition. European Journal of Cognitive Psychology, 19, 103-118  PDF 
 ABSTRACT 

The perceptual fluency/attributional model of the mere-exposure effect proposed by R. F. Bornstein and P. D’Agostino (1992) predicts that when recognition of a previously presented stimulus is above chance, feelings of fluency associated with that stimulus are discounted and thus the amount of fluency (mis)attributed to liking is reduced. This correction process results in smaller mere-exposure effects for supraliminal stimuli than for ‘‘subliminal’’ stimuli because when recognition is below chance participants are unaware of the source of fluency and they do not engage in correction. We tested this prediction in three experiments by presenting photographs of faces (Experiments 1 and 2) and polygons (Experiment 3) at varying exposure frequencies for 40 ms and 400 ms durations. Contrary to the prediction of the model, a significant mere-exposure effect was only found when recognition performance was at its highest level. Furthermore, across the three experiments liking and recognition were positively correlated.



2006
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Newell, B.R., & Fernandez, D. (2006). On the binary quality of recognition and the inconsequentiality of further knowledge: Two critical tests of the recognition heuristic. Journal of Behavioral Decision Making, 19, 333-346  PDF 
 ABSTRACT 

The recognition heuristic is claimed to be distinguished from notions of availability and fluency through its categorical or ‘‘binary’’ treatment of information and the ‘‘inconsequentiality’’ of further knowledge to inferences based on recognition. Using the citysize task of Goldstein and Gigerenzer (2002) we demonstrate that: (1) increasing the validity of other information in the environment decreases the reliance on recognition; (2) cities that are both recognized and have other information known about them (e.g. they have a soccer team) are chosen more often than those which are simply recognized; and (3) there is a negative correlation between the time taken to identify a city and the proportion of times it is selected as the larger of a pair. None of these results is predicted by the process model of the recognition heuristic. The implication of the results for the distinction between the recognition, availability and fluency heuristics is discussed.


Lagnado, D.A., Newell, B.R., Kahan, S., & Shanks, D.R. (2006). Insight and strategy in multiple cue learning. Journal of Experimental Psychology: General, 135, 162-183  PDF 
 ABSTRACT 

In multiple-cue learning (also known as probabilistic category learning) people acquire information about cue-outcome relations and combine these into predictions or judgments. Previous researchers claimed that people can achieve high levels of performance without explicit knowledge of the task structure or insight into their own judgment policies. It has also been argued that people use a variety of suboptimal strategies to solve such tasks. In three experiments the authors reexamined these conclusions by introducing novel measures of task knowledge and self-insight and using “rolling regression” methods to analyze individual learning. Participants successfully learned a four-cue probabilistic environment and showed accurate knowledge of both the task structure and their own judgment processes. Learning analyses suggested that the apparent use of suboptimal strategies emerges from the incremental tracking of statistical contingencies in the environment.


Enkvist, T., Newell, B.R., Juslin, P. & Olsson, H. (2006). On the role of causal intervention in multiple cue judgment: Positive and negative effects on learning. Journal of Experimental Psychology: Learning, Memory & Cognition, 32, 163-179  PDF 
 ABSTRACT 

Previous studies have suggested better learning when people actively intervene rather than when they passively observe the stimuli in a judgment task. In 4 experiments, the authors investigated the hypothesis that this improvement is associated with a shift from exemplar memory to cue abstraction. In a multiple-cue judgment task with continuous cues, the data replicated the improvement with intervention and participants who experimented more actively produced more accurate judgments. In a multiple-cue judgment task with binary cues, intervention produced poorer accuracy and participants who experimented more actively produced poorer judgments. These results provide no support for a representational shift but suggest that the improvement with active intervention may be limited to certain tasks and environments.



2005
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Rakow, T., Newell, B.R., Fayers, K., & Hersby, M. (2005). Evaluating three criteria for establishing cue-search hierarchies in inferential judgment. Journal of Experimental Psychology: Learning, Memory & Cognition, 31, 1088-1104  PDF 
 ABSTRACT 

The authors identify and provide an integration of 3 criteria for establishing cue-search hierarchies in inferential judgment. Cues can be ranked by information value according to expected information gain (Bayesian criterion), cue-outcome correlation (correlational criterion), or ecological validity (accuracy criterion). All criteria significantly predicted information acquisition behavior; however, in 3 experiments, the most successful predictor was the correlational criterion (followed by the Bayesian). Although participants showed sensitivity to task constraints, searching for less information when it was more expensive (Experiment 1) and when under time constraints (Experiment 2), concomitant changes in the relative frequency of acquisition of cues with different information values were not observed. A rational analysis illustrates why such changes in the frequency of acquisition would be beneficial, and reasons for the failure to observe such behavior are discussed.


Newell, B.R. (2005). Re-visions of rationality? Trends in Cognitive Sciences, 9, 11-15  PDF 
 ABSTRACT 

The appeal of simple algorithms that take account of both the constraints of human cognitive capacity and the structure of environments has been an enduring theme in cognitive science. A novel version of such a boundedly rational perspective views the mind as containing an ‘adaptive toolbox’ of specialized cognitive heuristics suited to different problems. Although intuitively appealing, when this version was proposed, empirical evidence for the use of such heuristics was scant. I argue that in the light of empirical studies carried out since then, it is time this ‘vision of rationality’ was revised. An alternative view based on integrative models rather than collections of heuristics is proposed.


Taylor, R.P., Spehar, B., Wise, J.A., Clifford, C.W.G., Newell, B.R., Hagerhall, C.M., Purcell, T., & Martin, T.P. (2005). Perceptual and physiological responses to the visual complexity of Pollock’s dripped fractal patterns, Non-linear Dynamics. Psychology & Life Sciences, 9, 89-114

2004
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Newell, B.R., & Shanks, D.R. (2004). On the role of recognition in decision making. Journal of Experimental Psychology: Learning, Memory & Cognition, 30, 923-935  PDF 
 ABSTRACT 

In 2 experiments, the authors sought to distinguish between the claim that recognition of an object is treated simply as a cue among others for the purposes of decision making in a cue-learning task from the claim that recognition is attributed a special status with fundamental, noncompensatory properties. Results of both experiments supported the former interpretation. When recognition had a high predictive validity, it was relied on (solely) by the majority of participants; however, when other cues in the environment had higher validity, recognition was ignored, and these other cues were used. The results provide insight into when, where, and why recognition is used in decision making and also question the elevated status assigned to recognition in some frameworks (e.g., D. G. Goldstein & G. Gigerenzer, 2002).


Newell, B.R., Rakow. T., Weston, N.J., & Shanks, D.R. (2004). Search strategies in decision making: The success of “success”. Journal of Behavioral Decision Making, 17, 117-137  PDF 
 ABSTRACT 

Examination of search strategies has tended to focus on choices determined by decision makers’ personal preferences among relevant cues, and not on learning cue-criterion relationships. We present an empirical and rational analysis of cue search for environments with objective criteria. In such environments, cues can be evaluated on the basis of three properties: validity (the probability that a cue identifies the correct choice if cue values differ between alternatives); discrimination rate (the proportion of occasions on which a cue has differing values); and success (the expected proportion of correct choices when only that cue can be used). Our experiments show that though there is a high degree of individual variability, success is a key determinant of search. Furthermore, a rational analysis demonstrates why success-directed search is the most adaptive strategy in many circumstances.


Newell, B.R., & Andrews, S. (2004). Levels of processing effects on implicit and explicit memory tasks: Using question position to investigate the lexical processing hypothesis. Experimental Psychology, 51, 132-144  PDF 
 ABSTRACT 

One interpretation of levels of processing effects (LOP) on priming in implicit tests of memory is in terms of deficits in lexical processing during shallow study tasks. In two experiments the extent of lexical processing engaged in during standard shallow encoding tasks was manipulated by placing the encoding question either before or after the target stimulus. Clear evidence was found in explicit memory tasks that placing the question after the target stimulus increased the depth of processing of words presented in shallow encoding tasks. In contrast, there was no evidence of such an effect on the priming observed in implicit memory tasks. The results suggest that the role of lexical processing in LOP effects on priming requires further specification.



2003
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Newell, B.R., Weston, N.J., & Shanks, D.R. (2003). Empirical tests of a fast and frugal heuristic: Not everyone “takes-the-best”. Organizational Behavior and Human Decision Processes, 91, 82-96  PDF 
 ABSTRACT 

The fast-and-frugal heuristics approach to decision making under uncertainty advocated by Gigerenzer and colleagues (e.g., Gigerenzer & Goldstein,1996) has achieved great popularity despite a relative lack of empirical validation. We report two experiments that examine the use of one particular heuristic—‘‘take-the-best’’ (TTB). In both experiments the majority of participants adopted frugal strategies,but only one-third (33%) behaved in a manner completely consistent with TTBs search,stopping and decision rules. Furthermore,a significant proportion of participants in both experiments adopted a non-frugal strategy in which they accumulated more information than was predicted by TTBs stopping rule. The results provide an insight into the conditions under which different heuristics are used,and question the predictive power of the fast-and-frugal approach.


Newell, B.R., & Shanks, D.R. (2003). Take the best or look at the rest? Factors influencing ‘one-reason’ decision-making. Journal of Experimental Psychology: Learning, Memory & Cognition, 29, 53-65  PDF 
 ABSTRACT 

Aspects of an experimental environment were manipulated in 3 experiments to examine the parameters under which the “take-the-best” (TTB) heuristic (e.g., G. Gigerenzer & D. G. Goldstein, 1996) operates. Results indicated TTB use to be more prevalent when the cost of information was high, when validities of the cues were known, and when a deterministic environment was used. However, large individual variability in strategy use was observed as well as a significant proportion of behavior inconsistent with TTB, expecially its stopping rule. The results demarcate some of the heuristic’s boundary conditions and also question the validity of TTB as a psychologically plausible and pervasive model of behavior.


Newell, B.R., & Bright, J.E.H. (2003). The subliminal mere exposure effect does not generalize to structurally related stimuli. Canadian Journal of Experimental Psychology, 57, 61-68  PDF 
 ABSTRACT 

R.F. Bornstein (1994) questioned whether subliminal mere exposure effects might generalize to structurally related stimuli, thereby providing evidence for the existence of implicit learning. Two experiments examined this claim using letter string stimuli constructed according to the rules of an artificial grammar. Experiment 1 demonstrated that brief, masked exposure to grammatical strings impaired recognition but failed to produce a mere exposure effect on novel structurally related strings seen at test. Experiment 2 replicated this result but also demonstrated that a reliable mere exposure effect could be obtained, provided the same grammatical strings were presented at test. The results suggest that the structural relationship between training and test items prevents the mere exposure effect when participants are unaware of the exposure status of stimuli, and therefore provide no evidence for the existence of implicit learning.


Spehar, B., Clifford, C.W.G, Newell, B.R., & Taylor, R.P. (2003). Universal aesthetic of fractals. Computers and Graphics, 27, 813-820  PDF 
 ABSTRACT 

Since their discovery by Mandelbrot (The Fractal Geometry of Nature, Freeman, New York, 1977), fractals have experienced considerable success in quantifying the complex structure exhibited by many natural patterns and have captured the imaginations of scientists and artists alike. With ever-widening appeal, they have been referred to both as ‘‘fingerprints of nature’’ (Nature 399 (1999) 422) and ‘‘the new aesthetics’’ (J. Hum. Psychol. 41 (2001) 59). Here, we show that humans display a consistent aesthetic preference across fractal images, regardless of whether these images are generated by nature’s processes, by mathematics, or by the human hand.



2002
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Newell, B.R., & Bright, J.E.H. (2002). Evidence against hyperspecificity in implicit invariant learning. Quarterly Journal of Experimental Psychology, Section A, 55, 1109 -1126  PDF 
 ABSTRACT 

Four experiments examined the claim that cross-format transfer in invariant learning is reliant solely on the presence of repetition structure in study and teststrings (Stadler, Warren, & Lesch, 2000).Experiments 1, 2, and 3 used strings with no repetitions and found significant cross-format transfer in combination with a non-significant transfer decrement—no significant difference between same- and changed-format conditions. Further investigation of the basis of the role of repetition structure revealed an emphasis on the perceptual salience of test stimuli (Experiment 4). Our results contrast with those of Stadler et al. and suggest that under the conditions we employed invariant learning is not highly sensitive to changes in the perceptual characteristics of stimuli and therefore is inaccurately described as hyperspecific. We suggest that the term hyperspecific be reserved for cases in which minor format changes result in significant perfor- mance impairments—for example, typographical effects in implicit memory.


Newell, B.R., & Bright, J.E.H. (2002). Well past midnight: Calling time on implicit invariant learning? European Journal of Cognitive Psychology, 14, 185-205  PDF 
 ABSTRACT 

Three experiments are reported that examine the nature of knowledge underlying performance in the invariant learning task. Previous research (Bright & Burton, 1994; McGeorge & Burton, 1990) has supported an account of perfor- mance based on the implicit abstraction and application of a rule pertaining to the invariant feature. In contrast, we found effects in both the digit and clock invariant tasks that are difficult to explain solely in terms of subjects acquiring the experimenters’ rule. In all three experiments, manipulation of test item properties that are independent of the invariant feature led to a detriment in performance that is not predicted by an account based on the experimenters’ rules. Furthermore, the use of an on-line measure of awareness (confidence ratings) provided some evidence that performance is mediated by low confidence expli- cit knowledge.



2001
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Newell, B.R., & Bright, J.E.H. (2001). The relationship between the structural mere exposure effect and the implicit learning process. Quarterly Journal of Experimental Psychology, 54, 1087-1104  PDF 
 ABSTRACT 

Three experiments are reported that investigate the relationship between the structural mere exposure effect (SMEE) and implicit learning in an artificial grammar task. Subjects were presented with stimuli generated from a finite-state grammar and were asked to memorize them. In a subsequent test phase subjects were required first to rate how much they liked novel items, and second whether or not they thought items conformed to the rules of the grammar. A small but consistent effect of grammaticality was found on subjects’ liking ratings (a “structural mere exposure effect”) in all three experiments, but only when encoding and testing conditions were consistent. A change in the surface representation of stimuli between encoding and test (Experiment 1), memorizing fragments of items and being tested on whole items (Experiment 2), and a mismatch of processing operations between encoding and test (Experiment 3) all removed the SMEE. In contrast, the effect of grammaticality on rule judgements remained intact in the face of all three manipulations. It is suggested that rule judgements reflect attempts to explicitly recall information about training items, whereas the SMEE can be explained in terms of an attribution of processing fluency.



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