Who shows the Unlikelihood Effect - and why?

Recent work shows that people judge an outcome as less likely when they learn the probabilities of all single pathways that lead to that outcome, a phenomenon termed the Unlikelihood Effect. The initial explanation for this effect is that the low pathway probabilities trigger thoughts that deem the outcome unlikely. We tested the alternative explanation that the effect results from people's erroneous interpretation and processing of the probability information provided in the paradigm. By reanalyzing the original experiments, we discovered that the Unlikelihood Effect had been substantially driven by a small subset of people who give extremely low likelihood judgments. We conducted six preregistered experiments, showing that these people are unaware of the total outcome probability and do formally incorrect calculations with the given probabilities. Controlling for these factors statistically and experimentally reduced the proportion of people giving extremely low likelihood judgments, reducing and sometimes eliminating the Unlikelihood Effect. Our results confirm that the Unlikelihood Effect is overall a robust empirical phenomenon, but suggest that the effect results at least to some degree from a few people's difficulties with encoding, understanding, and integrating probabilities. Our findings align with current research on other psychological effects, showing that empirical effects can be caused by participants engaging in qualitatively different mental processes.

Inside Ockham's razor: A mechanism driving preferences for simpler explanations

People often prefer simpler explanations, defined as those that posit the presence of fewer causes (e.g., positing the presence of a single cause, Cause A, rather than two causes, Causes B and C, to explain observed effects). Here, we test one hypothesis about the mechanisms underlying this preference: that people tend to reason as if they are using "agnostic" explanations, which remain neutral about the presence/absence of additional causes (e.g., comparing "A" vs. "B and C," while remaining neutral about the status of B and C when considering "A," or of A when considering "B and C"), even in cases where "atheist" explanations, which specify the absence of additional causes (e.g., "A and not B or C" vs. "B and C and not A"), are more appropriate. Three studies with US-based samples (total N = 982) tested this idea by using scenarios for which agnostic and atheist strategies produce diverging simplicity/complexity preferences, and asking participants to compare explanations provided in atheist form. Results suggest that people tend to ignore absent causes, thus overgeneralizing agnostic strategies, which can produce preferences for simpler explanations even when the complex explanation is objectively more probable. However, these unwarranted preferences were reduced by manipulations that encouraged participants to consider absent causes: making absences necessary to produce the effects (Study 2), or describing absences as causes that produce alternative effects (Study 3). These results shed light on the mechanisms driving preferences for simpler explanations, and on when these mechanisms are likely to lead people astray.

Rethinking Rationality

We seek to understand rational decision making and if it exists whether finite (bounded) agents may be able to achieve its principles. This aim has been a singular objective throughout much of human science and philosophy, with early discussions identified since antiquity. More recently, there has been a thriving debate based on differing perspectives on rationality, including adaptive heuristics, Bayesian theory, quantum theory, resource rationality, and probabilistic language of thought. Are these perspectives on rationality mutually exclusive? Are they all needed? Do they undermine an aim to have rational standards in decision situations like politics, medicine, legal proceedings, and others, where there is an expectation and need for decision making as close to "optimal" as possible? This special issue brings together representative contributions from the currently predominant views on rationality, with a view to evaluate progress on these and related questions.

How the Custom Suppresses the Endowment Effect: Exchange Paradigm in Kanak Country

In this paper, Knetsch's exchange paradigm is analyzed from the perspective of pragmatics and social norms. In this paradigm the participant, at the beginning of the experiment, receives an object from the experimenter and at the end, the same experimenter offers to exchange the received object for an equivalent object. The observed refusal to exchange is called the endowment effect. We argue that this effect comes from an implicature made by the participant about the experimenter's own expectations. The participant perceives the received item as a gift, or as a present, from the experimenter that cannot be exchanged as stipulated by the social norms of western politeness common to both the experimenter and the participant. This implicature, however, should not be produced by participants from Kanak culture for whom the perceived gift of a good will be interpreted as a first act of exchange based on gift and counter-gift. This exchange is a natural, frequent, balanced, and indispensable act for all Kanak social bonds whether private or public. Kanak people also know the French social norms that they apply in their interactions with French people living in New Caledonia. In our experiment, we show that when the exchange paradigm takes place in a French context, with a French experimenter and in French, the Kanak participant is subject to the endowment effect in the same way as a French participant. On the other hand, when the paradigm is carried out in a Kanak context, with a Kanak experimenter and in the vernacular language, or in a Kanak context that approaches the ceremonial of the custom, the endowment effect is no longer observed. The same number of Kanak participants accept or refuse to exchange the endowed item. These results, in addition to providing a new explanation for the endowment effect, highlight the great flexibility of decisions according to social-cultural context.

Quantum Cognition

Uncertainty is an intrinsic part of life; most events, affairs, and questions are uncertain. A key problem in behavioral sciences is how the mind copes with uncertain information. Quantum probability theory offers a set of principles for inference, which align well with intuition about psychological processes in certain cases: cases when it appears that inference is contextual, the mental state changes as a result of previous judgments, or there is interference between different possibilities. We motivate the use of quantum theory in cognition and its key characteristics. For each of these characteristics, we review relevant quantum cognitive models and empirical support. The scope of quantum cognitive models encompasses fallacies in decision-making (such as the conjunction fallacy or the disjunction effect), question order effects, conceptual combination, evidence accumulation, perception, over-/underdistribution effects in memory, and more. Quantum models often formalize psychological ideas previously expressed in heuristic terms, allow unified explanations of previously disparate findings, and have led to several surprising, novel predictions. We also cast a critical eye on quantum models and consider some of their shortcomings and issues regarding their further development. Expected final online publication date for the Annual Review of Psychology, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Pragmatics in the False-Belief Task: Let the Robot Ask the Question!

The poor performances of typically developing children younger than 4 in the first-order false-belief task "Maxi and the chocolate" is analyzed from the perspective of conversational pragmatics. An ambiguous question asked by an adult experimenter (perceived as a teacher) can receive different interpretations based on a search for relevance, by which children according to their age attribute different intentions to the questioner, within the limits of their own meta-cognitive knowledge. The adult experimenter tells the child the following story of object-transfer: "Maxi puts his chocolate into the green cupboard before going out to play. In his absence, his mother moves the chocolate from the green cupboard to the blue one." The child must then predict where Maxi will pick up the chocolate when he returns. To the child, the question from an adult (a knowledgeable person) may seem surprising and can be understood as a question of his own knowledge of the world, rather than on Maxi's mental representations. In our study, without any modification of the initial task, we disambiguate the context of the question by (1) replacing the adult experimenter with a humanoid robot presented as "ignorant" and "slow" but trying to learn and (2) placing the child in the role of a "mentor" (the knowledgeable person). Sixty-two typical children of 3 years-old completed the first-order false belief task "Maxi and the chocolate," either with a human or with a robot. Results revealed a significantly higher success rate in the robot condition than in the human condition. Thus, young children seem to fail because of the pragmatic difficulty of the first-order task, which causes a difference of interpretation between the young child and the experimenter.

Broken Physics: A Conjunction-Fallacy Effect in Intuitive Physical Reasoning

One remarkable aspect of human cognition is our ability to reason about physical events. This article provides novel evidence that intuitive physics is subject to a peculiar error, the classic conjunction fallacy, in which people rate the probability of a conjunction of two events as more likely than one constituent (a logical impossibility). Participants viewed videos of physical scenarios and judged the probability that either a single event or a conjunction of two events would occur. In Experiment 1 (n = 60), participants consistently rated conjunction events as more likely than single events for the same scenes. Experiment 2 (n = 180) extended these results to rule out several alternative explanations. Experiment 3 (n = 100) generalized the finding to different scenes. This demonstration of conjunction errors contradicts claims that such errors should not appear in intuitive physics and presents a serious challenge to current theories of mental simulation in physical reasoning.

Perspectives on Correctness in Probabilistic Inference from Psychology

Research into decision making has enabled us to appreciate that the notion of correctness is multifaceted. Different normative framework for correctness can lead to different insights about correct behavior. We illustrate the shifts for correctness insights with two tasks, the Wason selection task and the conjunction fallacy task; these tasks have had key roles in the development of logical reasoning and decision making research respectively. The Wason selection task arguably has played an important part in the transition from understanding correctness using classical logic to classical probability theory (and information theory). The conjunction fallacy has enabled a similar shift from baseline classical probability theory to quantum probability. The focus of this overview is the latter, as it represents a novel way for understanding probabilistic inference in psychology. We conclude with some of the current challenges concerning the application of quantum probability theory in psychology in general and specifically for the problem of understanding correctness in decision making.

How to Get Rid of the Belief Bias: Boosting Analytical Thinking via Pragmatics

The previous research attempts to reduce the influence of the belief bias on deductive thinking have often been unsuccessful and, when they succeeded, they failed to replicate. In this paper, we propose a new way to see an old problem. Instead of considering the analytical abilities of the respondent, we focus on the communicative characteristics of the experimental task. By changing the pragmatics into play through a subtle manipulation of the instruction of the syllogism problem, we obtained a strong improvement in the accuracy of the performance in both untrained and trained in logic respondents. We suggest that current models of deductive thinking should be broadened to consider also communicative understanding as part of the processing of the problem.

Is There a Conjunction Fallacy in Legal Probabilistic Decision Making?

Classical probability theory (CPT) has represented the rational standard for decision making in human cognition. Even though CPT has provided many descriptively excellent decision models, there have also been some empirical results persistently problematic for CPT accounts. The tension between the normative prescription of CPT and human behavior is particularly acute in cases where we have higher expectations for rational decisions. One such case concerns legal decision making from legal experts, such as attorneys and prosecutors and, more so, judges. In the present research we explore one of the most influential CPT decision fallacies, the conjunction fallacy (CF), in a legal decision making task, involving assessing evidence that the same suspect had committed two separate crimes. The information for the two crimes was presented consecutively. Each participant was asked to provide individual ratings for the two crimes in some cases and conjunctive probability rating for both crimes in other cases, after all information had been presented. Overall, 360 probability ratings for guilt were collected from 120 participants, comprised of 40 judges, 40 attorneys and prosecutors, and 40 individuals without legal education. Our results provide evidence for a double conjunction fallacy (in this case, a higher probability of committing both crimes than the probability of committing either crime individually), in the group of individuals without legal education. These results are discussed in terms of their applied implications and in relation to a recent framework for understanding such results, quantum probability theory (QPT).

The Rationality of Risky Decisions

Over the years research in risky decision making has diagnosed variable degrees of irrationality in people's judgements and choices. In the 1960s an optimistic view dominated of a widely rational decision maker. The work of Tversky and Kahneman at the beginning of the 1970s led to a pessimistic view of basically flawed decision processes that frequently end up in `cognitive illusions'. In the 1980s a movement gained strength that pointed to the adaptiveness of seemingly irrational decisions. Recent work demonstrates that seemingly irrational choices may be due to different task construal between experimenters and participants. The respective evaluative change in what the rationality issue is generally taken to show is overdue, however. The negative message of fundamentally flawed human decision making has to be replaced by a more positive picture that acknowledges that some reactions to task and context are advantages rather than disadvantages of human decision making. Recent work on systems of thinking shows that different task construals can be meaningfully related to different systems of thinking, thus enabling a more unbiased treatment of the rationality issue.

Relation of Conditional Reasoning to Heuristic Processing

Wyer and Srull have proposed that a tendency to treat conditional relationships between events as if they were biconditional underlies a number of familiar biases in human social judgment. This hypothesis was tested in a factor-analytic study in which 111 subjects completed seven measures of heuristic use and three measures of conditional reasoning. A principal components analysis of the measures revealed two main factors, corresponding to an availability dimension and a representativeness dimension. There was no evidence for the hypothesis that the disposition to infer "Y is X" given "X is Y" underlies either dimension, although one measure of conditional reasoning, Wason's selection task, was related to both. This result is discussed in terms of Evans's two-stage (heuristic/analytic processing) model of reasoning.

The Linda Problem Revisited from the Perspective of Cognitive-Experiential Self-Theory

Results from four experiments (N = 548) support the hypothesis from cognitive-experiential self-theory (CEST) that the resistance of the notorious Linda conjunction problem to solution can be attributed primarily to its simultaneously concrete and unnatural context. The experiments demonstrated that the influence of other variables, such as problem order, event likelihood, within-versus between-protagonist context, and statistical sophistication, although important, cannot account for the robust influence of the combination of the concrete-abstract and natural-unnatural dimensions. The implications of the demonstration that virtually everyone has intuitive knowledge of the conjunction rule are discussed, in addition to cuing effects, narrative processing, and methodological issues that have produced serious distortions in the interpretation of previous research.

Can evolution get us off the hook? Evaluating the ecological defence of human rationality

This paper discusses the ecological case for epistemic innocence: does biased cognition have evolutionary benefits, and if so, does that exculpate human reasoners from irrationality? Proponents of 'ecological rationality' have challenged the bleak view of human reasoning emerging from research on biases and fallacies. If we approach the human mind as an adaptive toolbox, tailored to the structure of the environment, many alleged biases and fallacies turn out to be artefacts of narrow norms and artificial set-ups. However, we argue that putative demonstrations of ecological rationality involve subtle locus shifts in attributions of rationality, conflating the adaptive rationale of heuristics with our own epistemic credentials. By contrast, other cases also involve an ecological reframing of human reason, but do not involve such problematic locus shifts. We discuss the difference between these cases, bringing clarity to the rationality debate.

A methodological approach to ratio bias

The ratio-bias (RB) phenomenon is considered to provide systematic evidence of irrationality. When judging the probability of a low-probability event, many people judge it as less likely when it is expressed as a ratio of small numbers (e.g., 1-in-10) than when it is expressed as a ratio of large numbers (e.g., 10-in-100). Four experiments show that the phenomenon is increased by the experimental paradigm, which misleads subjects regarding the aim of the task by inducing equal-ratio neglect. One factor is constant across the texts of the Experiment 1–3: a particular sentence that induces subjects to neglect the equal ratio and invites them to express feelings about the outcome of the target event rather than giving a rational answer. This intent is strengthened by the formulation of the question (Experiment 1), which explicitly asks the subject to express the feeling connected to the lotteries and the absence of a third option (Experiment 1, 4), the right one, which expresses the “indifference” between the two options. In Experiment 4, the task lacks only the third option, and, simply by adding the option that allows subjects to express the correct answer, the RB disappears.

On the conjunction fallacy and the meaning of and, yet again: a reply to Hertwig, Benz, and Krauss (2008)

In this paper we question the theoretical tenability of Hertwig, Benz, and Krauss's (2008) (HBK) argument that responses commonly taken as manifestations of the conjunction fallacy should be instead considered as reflecting "reasonable pragmatic and semantic inferences" because the meaning of and does not always coincide with that of the logical operator ∧. We also question the relevance of the experimental evidence that HBK provide in support of their argument as well as their account of the pertinent literature. Finally, we report two novel experiments in which we employed HBK's procedure to control for the interpretation of and. The results obtained overtly contradict HBK's data and claims. We conclude with a discussion on the alleged feebleness of the conjunction fallacy, and suggest directions that future research on this topic might pursue.

Causal conjunction fallacies: The roles of causal strength and mental resources

In two experiments we tested the prediction derived from Tversky and Kahneman's (1983) work on the causal conjunction fallacy that the strength of the causal connection between constituent events directly affects the magnitude of the causal conjunction fallacy. We also explored whether any effects of perceived causal strength were due to graded output from heuristic Type 1 reasoning processes or the result of analytic Type 2 reasoning processes. As predicted, Experiment 1 demonstrated that fallacy rates were higher for strongly than for weakly related conjunctions. Weakly related conjunctions in turn attracted higher rates of fallacious responding than did unrelated conjunctions. Experiment 2 showed that a concurrent memory load increased rates of fallacious responding for strongly related but not for weakly related conjunctions. We interpret these results as showing that manipulations of the strength of the perceived causal relationship between the conjuncts result in graded output from heuristic reasoning process and that additional mental resources are required to suppress strong heuristic output.

"Falácia da conjunção": definição e variáveis de controle

A falácia da conjunção ocorre quando a conjunção de dois eventos é julgada como mais provável de ocorrer do que seus eventos constituintes. Esse fenômeno tem sido investigado principalmente por psicólogos cognitivistas, mas, recentemente, tem atraído o interesse de alguns analistas do comportamento. O presente trabalho consiste em um resumo da literatura sobre falácia, no qual são enfatizadas as estratégias metodológicas utilizadas e os resultados empíricos obtidos. Dentre as variáveis controladoras analisadas, são destacadas a representatividade, o uso inadequado de regras probabilísticas, as experiências passadas com os eventos constituintes e compostos, o treino estatístico e os aspectos verbais e contextuais.

Testing boundary conditions for the conjunction fallacy: effects of response mode, conceptual focus, and problem type

Two experiments used within-subject designs to examine how conjunction errors depend on the use of (1) choice versus estimation tasks, (2) probability versus frequency language, and (3) conjunctions of two likely events versus conjunctions of likely and unlikely events. All problems included a three-option format verified to minimize misinterpretation of the base event. In both experiments, conjunction errors were reduced when likely events were conjoined. Conjunction errors were also reduced for estimations compared with choices, with this reduction greater for likely conjuncts, an interaction effect. Shifting conceptual focus from probabilities to frequencies did not affect conjunction error rates. Analyses of numerical estimates for a subset of the problems provided support for the use of three general models by participants for generating estimates. Strikingly, the order in which the two tasks were carried out did not affect the pattern of results, supporting the idea that the mode of responding strongly determines the mode of thinking about conjunctions and hence the occurrence of the conjunction fallacy. These findings were evaluated in terms of implications for rationality of human judgment and reasoning.

An evaluation of dual-process theories of reasoning

Current theories propose that reasoning comprises two underlying systems (Evans & Over, 1996; Sloman, 1996; Stanovich & West, 2000). The systems are identified as having functionally distinct roles, differ according to the type of information encoded, vary according to the level of expressible knowledge, and result in different responses. This article evaluates the arguments and the evidence from a select number of key tasks that have been supportive of dual-reasoning theorists' proposals. The review contrasts the dualist approach with a single-system framework that conjectures that different types of reasoning arise through the graded properties of the representations that are utilized while reasoning, and the different functional roles that consciousness has in cognition. The article concludes by arguing in favor of the alternative framework, which attempts to unify thedifferent forms of reasoning identified by dual-process theorists under a single system.

A perspective on judgment and choice: mapping bounded rationality

Early studies of intuitive judgment and decision making conducted with the late Amos Tversky are reviewed in the context of two related concepts: an analysis of accessibility, the ease with which thoughts come to mind; a distinction between effortless intuition and deliberate reasoning. Intuitive thoughts, like percepts, are highly accessible. Determinants and consequences of accessibility help explain the central results of prospect theory, framing effects, the heuristic process of attribute substitution, and the characteristic biases that result from the substitution of nonextensional for extensional attributes. Variations in the accessibility of rules explain the occasional corrections of intuitive judgments. The study of biases is compatible with a view of intuitive thinking and decision making as generally skilled and successful.

Rationality

This chapter reviews selected findings in research on reasoning, judgment, and choice and considers the systematic ways in which people violate basic requirements of the corresponding normative analyses. Recent objections to the empirical findings are then considered; these objections question the findings' relevance to assumptions about rationality. These objections address the adequacy of the tasks used in the aforementioned research and the appropriateness of the critical interpretation of participants' responses, as well as the justifiability of some of the theoretical assumptions made by experimenters. The objections are each found not to seriously impinge on the general conclusion that people often violate tenets of rationality in inadvisable ways. In the process, relevant psychological constructs, ranging from cognitive ability and need for cognition, to dual process theories and the role of incentives, are discussed. It is proposed that the rationality critique is compelling and rightfully gaining influence in the social sciences in general.

On the reality of the conjunction fallacy

Attributing higher "probability" to a sentence of form p-and-q, relative to p, is a reasoning fallacy only if (1) the word probability carries its modern, technical meaning and (2) the sentence p is interpreted as a conjunct of the conjunction p-and-q. Legitimate doubts arise about both conditions in classic demonstrations of the conjunction fallacy. We used betting paradigms and unambiguously conjunctive statements to reduce these sources of ambiguity about conjunctive reasoning. Despite the precautions, conjunction fallacies were as frequent under betting instructions as under standard probability instructions.

Do frequency representations eliminate conjunction effects? An exercise in adversarial collaboration

The present article offers an approach to scientific debate called adversarial collaboration. The approach requires both parties to agree on empirical tests for resolving a dispute and to conduct these tests with the help of an arbiter. In dispute were Hertwig's claims that frequency formats eliminate conjunction effects and that the conjunction effects previously reported by Kahneman and Tversky occurred because some participants interpreted the word “and” in “bank tellers and feminists” as a union operator. Hertwig proposed two new conjunction phrases, “and are” and “who are,” that would eliminate the ambiguity. Kahneman disagreed with Hertwig's predictions for “and are,” but agreed with his predictions for “who are.” Mellers served as arbiter. Frequency formats by themselves did not eliminate conjunction effects with any of the phrases, but when filler items were removed, conjunction effects disappeared with Hertwig's phrases. Kahneman and Hertwig offer different interpretations of the findings. We discuss the benefits of adversarial collaboration over replies and rejoinders, and present a suggested protocol for adversarial collaboration.

Partitive Formulation of Information in Probabilistic Problems: Beyond Heuristics and Frequency Format Explanations

I propose a simple theory on the use of base rate according to which neither heuristic nor frequentist factors underlie demonstrations of the occurrence or the elimination of the base-rate fallacy. According to this view, what is crucial for the occurrence or elimination of the base-rate fallacy is the absence or presence, respectively, of what can be called a partitive formulation (Macchi, 1995) of the conditional likelihood datum. A partitive formulation defines the set of which the numerical datum is a part (in terms of percentages or frequencies) by referring to the likelihood datum relative to the base rate information. The predictive power of this hypothesis is shown by comparing responses to different versions of problems containing the same implied natural heuristic principles and supplied data, but which differ in the way the information is presented (partitive vs nonpartitive). Whether probabilistic or frequentist, the partitive versions lead to an almost complete elimination of the bias which remains when nonpartitive versions are used. On the basis of these experimental results, the paper includes a critical discussion of heuristic, frequentist, and mental models theories. Copyright 2000 Academic Press.