M. Oaksford and N. Chater presented a Bayesian analysis of the Wason selection task in which they proposed that people choose cards in order to maximize expected information gain as measured by reduction in uncertainty in the Shannon-Weaver information theory sense. It is argued that the EIG measure is both psychologically implausible and normatively inadequate as a measure of epistemic utility. The article is also concerned with the descriptive account of findings in the selection task literature (...) offered by Oaksford and Chater. First, it is shown that their analysis data reported in the recent article of K. N. Kirby is unsound; second, an EIG analysis is presented of the experiments of P. Pollard and J. St. B. T. Evans that provides a strong empirical disconfirmation of the theory. (shrink)

We tested the hypothesis that choices determined by Type 1 processes are compelling because they are fluent, and for this reason they are less subject to analytic thinking than other answers. A total of 104 participants completed a modified version of Wason's selection task wherein they made decisions about one card at a time using a two-response paradigm. In this paradigm participants gave a fast, intuitive response, rated their feeling of rightness for that response, and were then allowed (...) free time to reconsider their answers. As we predicted, answers consistent with a matching heuristic were made more quickly than other answers, were given higher FOR ratings, and received less subsequent analysis as measured by rethinking time and the probability of changing answers. These data suggest that reasoning biases may be compelling because they are fluently generated; this is turn creates a strong FOR, which acts as a signal that further analysis is not necessary. (shrink)

Evolutionary psychology—in its ambitious version well formulated by Cosmides and Tooby (e.g., Cosmides & Tooby 1987, Tooby & Cosmides 1992) —will succeed to the extent that it causes cognitive psychologists to rethink central aspects of human cognition in an evolutionary perspective, to the extent, that is, that psychology in general becomes evolutionary. The human species is exceptional by its massive investment in cognition, and in forms of cognitive activity—language, metarepresentation, abstract thinking—that are as unique to humans as echolocation is unique (...) to bats. The promise of evolutionary psychology is thus to help explain not just traits of human psychology that are homologous to those of many other species, but also traits of human psychology that are genuinely exceptional and that in turn help explain the exceptional character of human culture and ecology. However, most of the work done in evolutionary psychology so far is on aspects of human psychology that are not specifically human except in their details. Showing, for instance, how human preferences in mate choice are fine -tuned in the way the theory of evolution would predict is of great interest (see e.g., Buss 1994) but it can be done on the basis of a relatively shallow psychology. This makes work on distinctly human adaptations involving higher cognition of particular importance for defenders of a psychologically ambitious evolutionary psychology. What is often presented (e.g., Pinker, 1997) as the signal achievement of cognitive evolutionary psychology in this respect is the experimental testing of Cosmides’ (1989) hypothesis that there exists an evolved competence to deal with social contracts, and, in particular to detect cheaters. We want to argue that, because of faulty methodological choices—the quasi-exclusive reliance on the four-cards selection task—, the hypothesis has in fact not yet been tested. The plan of this chapter is as follows: We begin, with a short presentation of Cosmides’s social contract hypothesis, of Wason selection task, and of Cosmides’s reasons to use the task in order to test the theory.. (shrink)

Wason’s selection task is a paramount experimental problem in the study of human reasoning, often connected with the celebrated ravens paradox in the philosophical literature. Various normative accounts of the selection task rely on a Bayesian approach. Some claim vindication of participants’ rationality. Others don’t, thus following Wason’s original intuition that observed responses are mistaken. In this article we argue that despite claims to the contrary, all these accounts actually speak to the same effect: Wason was (...) right. First, we provide a new accuracy-based analysis of the selection task that includes the existing proposals as special cases. We then show on this basis that none can actually vindicate participants’ rationality. We conclude that all normative renditions considered eventually concur: all in all, Bayesians should follow Wason in the selection task. (shrink)

The processes that guide performance in Wason's selection task (WST) are still under debate. The matching bias effect in the negations paradigm and its elimination by explicit negations are central arguments against a substantial role for inferential processes. Two WST experiments were conducted in the negations paradigm to replicate the basic finding and to compare effects of implicit and explicit negations. Results revealed robust matching bias in implicit negations. In contrast to previous findings, matching bias was reduced but (...) not eliminated in conditions using explicit negations. Model-based analyses suggest that matching bias is due to a switch towards a negative test strategy caused by negations. (shrink)

The main goal of the paper is to investigate the relation between indicative conditionals and rationality. We wil l do this by consider- ing several interpretations of a very wel l-known example of reasoning involving conditionals, that is the Wason selection task, and showing how those interpretations have different bearings on the notion of ra- tionality. In particular, in the first part of the paper, after having briefly presented the selection task, we wil l take a (...) look at two prag- matic responses to the chal lenge posed by the task, through Wason ’s notion of confirmation bias and Grice’s theory of conversational im- plicature. The second part wil l introduce Adams’ probabilistic view of indicative conditionals and wil l give reasons for preferring his account to those aforementioned. The conclusion wil l evaluate the question of human rationality in the light of the new standpoint acquired. -/-. (shrink)

A problem related to theWason selection task is that only some thematic versions of it are executed correctly. Fodor raises the thesis that the versions that are adequately solved are those that refer to deontic situations. In his opinion, there is a deontic logic that is different to classical logic and that allows reasoning appropriately in deontic contexts. In this paper, I review Fodor’s arguments, question his assumptions, and propose an alternative explanation, based on the mental models theory, (...) of why only some versions of the selection task with thematic content offer optimal results. (shrink)

People usually fail the Wason selection task, choosing P and Q cases, when attempting to validate descriptive rules having the form “If P, then Q.” Yet they solve it, selecting P and not-Q cases, when validating deontic rules of the form “If P, then must Q.” The field of evolutionary psychology has overwhelmingly interpreted deontic versions of the selection task in terms of a naturally-selected, domain-specific social-contract or cheating algorithm. This work has done much to promote (...) evolutionary psychology as an alternative to a mindblind sociobiology that ignores the computational structure of cognitive mechanisms in producing people's behaviors. Nevertheless, evolution-minded researchers outside cognitive psychology know little of the ample literature challenging this interpretation and uncritically cite the “cheater-detection module” as a key insight into human cognition. Although a priori arguments for a specially evolved cheater-detection module are plausible, the selection task provides no direct evidence for such a module. (shrink)

Hempel's paradox of the ravens has to do with the question of what constitutes confirmation from a logical point of view; Wason 's selection task has been used extensively to investigate how people go about attempting to confirm or disconfirm conditional claims. This paper presents an argument that the paradox is resolved, and that people's typical performance in the selection task can be explained, by consideration of what constitutes an effective strategy for seeking evidence of the (...) tenability of universal or conditional claims in everyday life. (shrink)

In a masked priming experimental paradigm, we studied a possible subliminal perception effect on a semantic selection task. To gauge the degree to which subjects solved the SST consciously, they subsequently reported their level of confidence of having made a correct response. This was done on each trial, and the subjects used individually constructed category rating scales to do so, in order to achieve a more sensitive measurement of which trials were influenced by conscious processes. During the construction (...) of these individual rating scales, subjects verbally reported their experiences after each trial. The present study failed to find evidence of performance above chance level when subjects themselves reported to be at chance level. In fact, performance closely covaried with subjects' confidence ratings. About half of the subjects reported they would sometimes experience a 'feeling of knowing' the correct response to the SST, despite being unaware of the specific identity of the prime. From this, we observe the methodological point that in order to demonstrate subliminal perception in a masked priming paradigm with a semantic selection task it is not enough to demonstrate a lack of conscious visual perception of the prime, since a vague, yet conscious, FOK experience can be used by subjects to solve the task. (shrink)

The cheater-detection (CD) hypothesis suggests that people who otherwise perform poorly on the Wason selection task perform well when the task is couched in cheater-detection contexts. We report three studies with new selection problems that are similar to the originals but that question the CD hypothesis. The first two studies document a pattern heretofore attributed to CD mechanisms, namely good performance with “regular” rules and inferior performance with “switched” rules, all in problems that lack a cheater-detection (...) context. The final study finds an interaction: not only is good performance elicited on non-CD problems, but poor performance is found in the context of CD problems. Performance on the selection task cannot be predicted based on the presence or absence of cheater-detection contexts, which brings into question the need to invoke a specialised cheater-detection module. (shrink)

Individual differences in performance on a variety of selection tasks were examined in three studies employing over 800 participants. Nondeontic tasks were solved disproportionately by individuals of higher cognitive ability. In contrast, responses on two deontic tasks that have shown robust performance facilitationthe Drinking-age Problem and the Sears Problem-were unrelated to cognitive ability. Performance on deontic and nondeontic tasks was consistently associated. Individuals in the correct/correct cell of the bivariate performance matrix were over-represented. That is, individuals giving the modal (...) response on a nondeontic task (P and Q) were significantly less likely to give the modal response on a deontic task (P and not-Q) than were individuals who made the non-modal P and not-Q selection on nondeontic problems. The implications of the results are discussed within the heuristic-analytic framework of Evans (1996; Evans & Over, 1996) and the optimal data selection model of Oaksford and Chater (1994). (shrink)

Two experiments are reported that employed think-aloud methods to test predictions concerning relevance effects and rationalisation processes derivable from Evans' (1996) heuristic-analytic theory of the selection task. Evans' account proposes that card selections are triggered by relevance-determining heuristics, with analytic processing serving merely to rationalise heuristically cued decisions. As such, selected cards should be associated with more references to both their facing and their hidden sides than rejected cards, which are not subjected to analytic rationalisation. Experiment 1 used (...) a standard selection-task paradigm, with negative components permuted through abstract conditional rules. Support was found for all heuristic-analytic predictions. This evidence was shown to be robust in Experiment 2, where "select - don't select" decisions were enforced for all cards. Both experiments also clarify the role played by secondary heuristics in cueing the consideration of hidden card values during rationalisation. We suggest that whilst Evans' heuristic-analytic model and Oaksford and Chater's (e.g., 2003) optimal data selection model can provide compelling accounts of our protocol findings, the mental models theory fares less well as an explanation of our full dataset. (shrink)

Two experiments using a realistic version of the selection task examined the relationship between participants' probability estimates of finding a counter example and their selections. Experiment 1 used everyday categories in the context of a scenario to determine whether or not the number of instances in a category affected the estimated probability of a counter-example. Experiment 2 modified the scenario in order to alter participants' estimates of finding a specific counter-example. Unlike Kirby 1994a, but consistent with his proposals, (...) both studies showed that probability estimates significantly predicted selection. Overall results point to the value of understanding selections in terms of their subjective expected utility. (shrink)

It has been reported as a robust effect that people are likely to select a matching case in the Wason selection task. For example, they usually select the 5 case, in the Wason selection task with the conditional "if an E, then a not-5". This was explained by the matching bias account that people are likely to regard a matching case as relevant to the truth of the conditional (Evans, 1998). However, because a positive concept usually (...) constructs a smaller set than its negative one does (a rarity assumption), it is more effective to get information on the truth of the conditional in a positive set than in a negative set. Thus the optimal data selection account can also explain the effect. The set size of Q and matching by introducing negation were manipulated independently in four experiments. From the results it was inferred that the so-called matching bias was an amalgam of two different cognitive components-relevance judgement by matching and optimal data selection. (shrink)

Oaksford and Chater (1994) proposed to analyse the Wason selection task as an inductive instead of a deductive task. Applying Bayesian statistics, they concluded that the cards that participants tend to select are those with the highest expected information gain. Therefore, their choices seem rational from the perspective of optimal data selection. We tested a central prediction from the theory in three experiments: card selection frequencies should be sensitive to the subjective probability of occurrence for (...) individual cards. In Experiment 1, expected frequencies of the p- and the q-card were manipulated independently by concepts referring to large vs. small sets. Although the manipulation had an effect on card selection frequencies, there was only a weak correlation between the predicted and the observed patterns. In the second experiment, relative frequencies of individual cards were manipulated more directly by explicit frequency information. In addition, participants estimated probabilities for the four logical cases and of the conditional statement itself. The experimental manipulations strongly affected the probability estimates, but were completely unrelated to card selections. This result was replicated in a third experiment. We conclude that our data provide little support for optimal data selection theory. (shrink)

Does reasoning occur on the Wason selection task, or are card selections determined purely on the basis of heuristic processes? To answer this question two relevance-based theories of reasoning are compared: (1) the theory of Evans (1984, 1989; Evans & Over, 1996), which takes the heuristic viewpoint, and (2) the theory of Sperber, Cara, and Girotto (1995), which takes the reasoning viewpoint. In three experiments, the effect of removing matching cards from the selection task array is (...) examined. It is argued that the Sperber et al. theory makes clearer predictions about the results of these manipulations, which are confirmed, and that the Evans theory can only accommodate them if it allows the operation of reasoning processes. The results are also discussed in relation to Roth's (1979) account of the selection task, mental models theory, and information gain theory. (shrink)

In Wason’s Selection Task, subjects: process information from the instructions and build a mental representation of the problem, then: select a course of action to solve the problem,under the constraints imposed by the instructions. We analyze both aspects as part of a constraint satisfaction problem without assuming Wason’s ‘logical’ solution to be the correct one. We show that outcome of step may induce mutually inconsistent constraints, causing subjects to select at step solutions that violate some of them. Our (...) analysis explains why inconsistent constraints are less likely disrupt non-abstract versions of the tasks, but unlike Bayesians does not posit different mechanisms in abstract and thematic variants. We then assess the logicality of the task, and conclude on cognitive tasks as coordination problems. (shrink)

Recent research on grapheme-colour synesthesia has focused on whether visual attention is necessary to induce a synesthetic percept. The current study investigated the influence of synesthesia on overt visual attention during an oculomotor target selection task. Chromatic and achromatic stimuli were presented with one target among distractors among multiple ‘5’s ). Participants executed an eye movement to the target. Synesthetes and controls showed a comparable target selection performance across conditions and a ‘pop-out effect’ was only seen in (...) the chromatic condition. As a pop-out effect was absent for the synesthetes in the achromatic condition, a synesthetic element appears not to elicit a synesthetic colour, even when it is the target. The synesthetic percepts are not pre-attentively available to distinguish the synesthetic target from synesthetic distractors when elements are presented in the periphery. Synesthesia appears to require full recognition to bind form and colour. (shrink)

We apply an algorithmic learning model of inquiry to model reasoning carried by experimental subjects in Wason's _Selection Task_ that represents reasoning in the task as computation of a decision tree that supervenes on semantic representations. We argue that the resulting model improves on previous probabilistic and pragmatic models of the task. In particular, it suggests that subjects' selection could in fact be guided by sophisticated patterns of argumentative reasoning.

En este trabajo se presenta una explicación para el problema de las versiones abstractas de la tarea de selección de las cuatro tarjetas de Peter Wason: los discretos resultados de los participantes cuando se enfrentan a ellas. Nuestra explicación apunta a que los sujetos no comprenden la regla de la tarea como un condicional, sino como un bicondicional, provocando tal circunstancia que no elijan las tarjetas correctas. Santamaría planteó una objeción para todo enfoque que defienda que en la tarea de (...) selección se produce una interpretación bicondicional de la regla, pero nosotros también respondemos aquí a dicha objeción atendiendo a la primacía que en el razonamiento humano puede tener la regla lógica del modus ponens. Igualmente, exponemos un estudio, basado en diálogos de seminario tutoriales al modo socrático, realizado por nosotros con el propósito de comprobar si nuestra explicación puede ser viable y comentamos los resultados obtenidos. In this paper, we present an explanation for the problem of the abstract versions of Peter Wason’s four-card selection task: modest subjects’ results when they are confronted with these tasks. Our explanation poses that individuals do not comprehend the task rule as a conditional sentence, but as a biconditional one, causing that subjects do not choose the correct cards. Santamaría presented an objection for any approach that suggests a biconditional interpretation in the task selection. In this work, we discuss this objection based on the apparent primacy of a logical rule in human reasoning: modus ponens. Additionally, we present a study based on Socratic dialogue seminars with a tutorial style, developed by us, to check whether our explanation is viable or not, and discuss the results achieved. (shrink)

Green, Over, and Pyne's (1997) paper (hereafter referred to as ''GOP") seems to provide a novel approach to examining probabilistic effects in Wason's selection task. However, in this comment, it is argued that their chosen experimental paradigm confounds most of their results. The task demands of the externalisation procedure (Green, 1995) enforce a correlation between card selections and the probability of finding a counterexample, which was the main finding of GOP's experiments. Consequently GOP cannot argue that their (...) data support Kirby's (1994) proposal that people's normal strategy in the selection task is to seek falsifying evidence. Despite this methodological problem, effects of the probability of the antecedent ( p ) of a conditional rule, if p then q , predicted by Kirby (1994) and by Oaksford and Chater (1994) were observed, although they were inconsistent between Experiments 1 and 2. Moreover, the probability estimates that GOP collected, which are not vulnerable to that methodological criticism, do support the idea that when P ( p ) > P ( q ), participants revise P ( p ) down as suggested by Oaksford and Chater (1994). (shrink)

Two experiments were conducted with variants of Wason's (1966) selection task. The common focus was the effect of differences in the sizes of the sets represented by P and not-Q in assertions of the form _If P then Q_ (conditional) or _All P are Q_ (categorical). Results support the conclusion that such set size differences affect the strategies people adopt when asked to determine, efficiently, the truth or falsity of such assertions, but they do not entirely negate the (...) tendency to select the term represented by P (the antecedent of the conditional or the subject of the categorical) in preference to the term represented by not-Q (the complement of the consequent of the conditional or the complement of the predicate of the categorical). Several possible explanations of this perseverance are considered. Results also support the conclusion that people find it easier to assess categorical assertions than logically equivalent conditional assertions. (shrink)

Participants attempted to solve a modified version of Wason's selection task. Variables were: sizes of the sets referenced by a specified assertion, form of the assertion, thematic content of the assertion, and the need for sampling or not. In Experiment 1, participants were given enough information to determine the truth or falsity of the specified assertion with certainty; in Experiment 2, they had to rely on sampling and could not determine the assertion's truth or falsity with certainty. Performance (...) was better in Experiment 1 than in Experiment 2, but in both cases much better than what is typically obtained with the conventional selection task. The results support the hypothesis that performance of the selection task is sensitive to the sizes of the sets involved, add credence to the conclusion that framing the task in a thematically meaningful way can facilitate performance, and demonstrate that facilitation does not require deontic reasoning or a well-known convention being involved. The relationship between expressed confidence and level of performance is consistent with other studies showing the former to be a good predictor of the latter. (shrink)

Mental models theorists have proposed that reasoners tend to focus on what is explicit in their mental models, and that certain debiasing procedures can induce them to direct their attention to other relevant information. For instance, Green and Larking 1995; also Green, 1995a facilitated performance on the Wason selection task by inducing participants to consider counterexamples to the conditional rule. However, these authors acknowledged that one aspect of their data might require some modification to the mental models theory. (...) This research is discussed here, and it is suggested that the results may be better accommodated by mental inference rules theory than by mental models theory. (shrink)

A problem related to theWason selection task is that only some thematic versions of it are executed correctly. Fodor raises the thesis that the versions that are adequately solved are those that refer to deontic situations. In his opinion, there is a deontic logic that is different to classical logic and that allows reasoning appropriately in deontic contexts. In this paper, I review Fodor’s arguments, question his assumptions, and propose an alternative explanation, based on the mental models theory, (...) of why only some versions of the selection task with thematic content offer optimal results. (shrink)

Two experiments were conducted to show that the IF … THEN … rules used in the different versions of Wason 's selection task are not psychologically—though they are logically—equivalent. Some of these rules are considered by the participants as strict logical conditionals, whereas others are interpreted as expressing a biconditional relationship. A deductive task was used jointly with the selection task to show that the original abstract rule is quite ambiguous in this respect, contrary to (...) deontic rules: the typical “error” made by most people may indeed be explained by the fact that they consider the abstract rule as a biconditional. Thus, there is no proper error or bias in the selection task as it is still argued, but a differential interpretation of the rule. The need for taking into account a pragmatic component in the process of reasoning is illustrated by the experiments. (shrink)

The probabilistic approach to human reasoning is exemplified by the information gain model for the Wason card selection task. Although the model is elegant and original, several key aspects of the model warrant further discussion, particularly those concerning the scope of the task and the choice process of individuals.

Taking a Darwinian approach, we propose that people reason to detect free-riders on the Wason Selection task with the sharing-rule; If one receives the resource, one is an in-group member (standard), or If one is an in-group member, one receives the resource (switched). As predicted, taking the resource-provider's perspective, both undergraduates and children (11 to 12 years old) checked for the existence of out-group members taking undeserved resource. Changing the perspective to that of the resource-recipient did not alter (...) the selection pattern in undergraduates, although the prediction was that another type of free-riding -failure to share by resource-provider- would be checked as well. However, by removing confounding factors in the materials, both undergraduates and children checked for both types of free-riding, which fully supports the prediction. These results indicate that the sharing-rule elicits a thematic content effect that cannot be explained by preceding deontic reasoning theories. (shrink)

We review the various explanations that have been offered toaccount for subjects'' behaviour in Wason ''s famous selection task. Weargue that one element that is lacking is a good understanding ofsubjects'' semantics for the key expressions involved, and anunderstanding of how this semantics is affected by the demands the taskputs upon the subject''s cognitive system. We make novel proposals inthese terms for explaining the major content effects of deonticmaterials. Throughout we illustrate with excerpts from tutorialdialogues which motivate the (...) kinds of analysis proposed. Our long termgoal is an integration of the various insights about conditionalreasoning on offer from different cognitive science methodologies. Thepurpose of this paper is to try to draw the attention of logicians andsemanticists to this area, since we believe that empirical investigationof the cognitive processes involved could benefit from semanticanalyses. (shrink)