The effect of instructions on performance in the Wason selection task

The effect of instructions on performance on the standard abstract form of Wason’s selection task was examined. Instructions to determine whether or not the statement is violated did not lead to an increase in correct responding, contrary to previous suggestions that such instructions would induce falsification strategies, but rather to an increase in verification bias. Instructions to determine whether the statement is true or false led to increased variability in performance, supporting the suggestion that such instructions are inherently ambiguous. Thus, the results demonstrate that the form of instructions can have a significant effect on performance in the selection task. Verification bias did better as an explanation of the data than did matching bias, which only fared well when its predictions coincided with those of verification bias. A substantial proportion of the data was unaccounted for by either of these strategies, which is consistent with the findings of a number of other recent studies.     

The effects of problem content and negation on Wason's selection task

The present study examined performance on Wason's selection task for two types of thematic content that have been shown to lead reliably to correct responding in this task. The four versions of the implication rule that are possible when negative components (antecedent and consequent) are allowed were used. This permitted a test of the hypothesis that matching bias and verification bias are cognitive short-circuiting strategies which are used when subjects have no prior experience with the problem content. In support of this hypothesis, facilitation was observed for the negated thematic rules when compared to performance on negated abstract rules. In addition, neither matching bias nor verification bias explained very well the data for negated abstract rules which were recodable into non-negative form. For both thematic and abstract problems, a fairly substantial percentage of the selections were unaccounted for with respect to processing strategy.     

Matching bias and set sizes: A discussion of Yama (2001)

Yama (2001) has presented an ingenious series of experiments in which he attempts to separate two accounts in the literature of the cause of “matching bias” in conditional reasoning. One account is that the bias arises from the way in which people process negations and the other is that it is due to the larger set sizes associated with negative propositions, rather than negation per se. Yama's experiments show influences of both negation and set size, from which he concludes that both factors contribute to the matching bias that is normally observed. In this note, it is argued that this conclusion is at odds with other findings in the literature, particularly those investigating implicit negation as the cause of the bias. Introducing explicit negations has been shown to remove matching bias completely and not partially, as Yama's account must predict. A possible reconciliation is proposed in terms of subtle contextual differences introduced by Yama's experiments.     

Negations and natural sampling in data selection: Ecological versus heuristic explanations of matching bias

Matching bias occurs when people ignore negations when testing a hypothesis--for example, if A, then not 2--and select possible data types that are named in the hypothesis (i.e., A and 2; Evans & Lynch, 1973). There are two explanations of this bias: the heuristic account and the contrast class account. The latter is part of Oaksford and Chater's (1994) ecological approach to data selection. On this account, a contrast set (i.e., birds that are not ravens) has a higher probability than the original set (i.e., birds that are ravens). This article reports two experiments in which these accounts make divergent predictions. The same materials were used as those in Yama (2001), who found more support for the heuristic approach. Experiment 1 replicated Yama with Western participants. Experiment 2 used a procedure introduced by Oaksford and Wakefield (2003). Rather than present participants with one of each of the four possible data types all at once, 50 were presented one at a time. The proportions of each data type reflected the relevant probabilities. The results supported the ecological approach, showing that people constructed contrast sets that strongly influenced their data selection behavior. The results were not consistent with the heuristic approach.     

Out of sight,out of mind: Matching bias underlies confirmatory visual search

Confirmation bias has recently been reported in visual search, where observers who were given a perceptual rule to test (e.g. “Is the p on a red circle?”) search stimuli that could confirm the rule stimuli preferentially (Rajsic, Wilson, & Pratt, Journal of Experimental Psychology: Human Perception and Performance, 41(5), 1353–1364, 2015). In this study, we compared the ability of concrete and abstract visual templates to guide attention using the visual confirmation bias. Experiment 1 showed that confirmatory search tendencies do not result from simple low-level priming, as they occurred when color templates were verbally communicated. Experiment 2 showed that confirmation bias did not occur when targets needed to be reported as possessing or not possessing the absence of a feature (i.e., reporting whether a target was on a nonred circle). Experiment 3 showed that confirmatory search also did not occur when search prompts referred to a set of visually heterogenous features (i.e., reporting whether a target on a colorful circle, regardless of the color). Together, these results show that the confirmation bias likely results from a matching heuristic, such that visual codes involved in representing the search goal prioritize stimuli possessing these features.     

Matching and oddity learning in the pigeon: Transfer effects and the absence of relational learning

Three experiments examined the extent to which pigeons trained on a matching or oddity discrimination with one pair of colours showed transfer when tested on a new matching or oddity discrimination with a new pair of colours. Experiment 1 examined the effects of key spacing and a delay procedure and replicated previous reports that in the transfer stage subjects given the same kind of problem (Non-shift condition) in general learn more rapidly than those given the opposite problem (Shift condition). However, this difference appeared only when pigeons given matching in both training and transfer stages were compared to those shifted from oddity to matching; it did not appear in birds transferred to oddity. Transfer was not significantly affected by key spacing or by the delay.

Experiments 2 and 3 examined transfer from a non-relational conditional discrimination based on one set of colours to a subsequent matching or oddity task based on two new colours. Both a comparison between the results of Experiment 1 and 2 and the corresponding within-experiment comparison from Experiment 3 showed that transfer from conditional training to matching was as great as from prior training on matching, while prior training on oddity produced negative transfer on shift to matching. It was suggested that this negative transfer occurs because pigeons trained on oddity have not learned to override an initial bias towards the odd stimulus in an array. Whatever the correct explanation; the present results provide no support for the claim that pigeons solve matching or oddity discriminations relationally.     

How reaction time measures elucidate the matching bias and the way negations are processed

Matching bias refers to the non-normative performance that occurs when elements mentioned in a rule do not correspond with those in a test item (e.g., consider the double mismatch between the rule If there is a not a T on the card then there is not a 4 and a card showing H6). One aim of the present work is to capture matching bias via reaction times as participants carry out truth-table evaluation tasks. Experiment 1 requires participants to verify conditional rules, and Experiment 2 to falsify them as the paradigm (a) employs four types of conditional sentences that systematically rotate negatives in the antecedent and consequent; and (b) presents predominantly cases having true antecedents. These experiments reveal that mismatching is linked to higher rates of incorrect responses and slower evaluation times. A second aim is to investigate the way not is processed. We compare a narrow view of negations, which argues that negation only denies information (e.g., not-T only says there is no T), to a search for alternatives view, which says that negations function to prime appropriate alternatives (e.g., not-T primes a search for other letters). Findings from both experiments support a narrow reading view.     

Conditional reasoning with negations: Implicit and explicit affirmation or denial and the role of contrast classes

' We report two studies on the effect of implicitly versus explicitly conveying affirmation and denial problems about conditionals. Recently Evans and Handley (1999) and Schroyens et al. (1999b, 2000b) showed that implicit referencing elicits matching bias: Fewer determinate inferences are made, when the categorical premise (e.g., B) mismatches the conditional's referred clause (e.g., A). Also, the effect of implicit affirmation (B affirms not-A) is larger than the effect of implicit denial (B denies A). Schroyens et al. hypothesised that this interaction is due to uncertainty in the case-wise affirmation of the contrast class of negated elements involved in implicit affirmations. In Experiment 1 we tested this hypothesis by manipulating the set size of the conditional clauses. The results confirm that binary sets, where the contrast class is a singleton, eliminate the differential effect of implicit affirmation and denial. With non-binary sets the interaction is not modulated by the scope of the contrast class (3, 5, 9 elements). Experiment 2 further investigated the role of contrast classes by using class inclusion to construct implicit affirmations (Mammal vs Mammal or Monkey) and implicit denial (No-Mammal vs Mammal or Monkey), in addition to the standard implicit problems mediated by contrast-class inclusion [(No-)Mammal/No-Mammal; Reptile; Snake). Findings indicate that class inclusion (Mammal/Monkey; Reptile/ Snake) only marginally affects performance, and is independent of the type of problem. This would suggest that the implicitness problem-type interaction is dependent on constructing contrast classes. However, the experiment failed to replicate the interaction, even on the subset of problems repeating the abstract letter/number format of Experiment 1. Moreover, with the natural binary set-sizes (vowels/consonants) the implicitness effect was eliminated entirely.     

Colour specificity in episodic and in perceptual object recognition with enhanced colour impact

In three experiments we investigated the perceptual specificity of explicit (old-new object recognition) and implicit memory (word-picture matching) for colour. In order to enhance the impact of colour on processing, we increased the number of colours per object and we impaired shape information. We presented multicoloured pictures (Experiment 1), blurred and partially occluded pictures (Experiment 2) and coloured line drawings in visual noise (Experiment 3). Experiments 1 and 2 had an intentional study phase; the study phase of Experiment 3 was an incidental colour or category naming task. Changing colour from study to test always had negative effects on episodic recognition although colour was irrelevant. In contrast, in the matching task old pictures were generally matched faster than new ones independent of their colour congruence. In Experiment 3, an additional small advantage of congruent colours and of semantic processing occurred. We conclude that two different memory representations contribute to these tasks. Changes of an achromatic, more abstract representation, that is used in normal object recognition, and a representation of the specific exemplar that includes colour. This latter token is used in episodic recognition as well as in unusual perceptual tasks (Experiment 3).     

Universal Connectives in the Selection Task

Two experiments using Wason's selection task are reported in this paper. Their main purpose was to test the meaning of universal connectives ( always and never ) against the hypothetical conditional connective ( if ). In the first experiment, these two different kinds of connectives were used with the same content and in logically equivalent situations. Results demonstrated that universal connectives yield different patterns of responses than do hypothetical connectives. People seem to consider the situation described in the task in the same way, irrespective of the use of negations, when universal connectives are used, but not when the if... then structure is used. The second experiment extended these results to a different content, and to an abstract version of the task. An explanation in terms of mental models is provided.     

Contrast classes and matching bias as explanations of the effects of negation on conditional reasoning

In this paper the arguments for optimal data selection and the contrast class account of negations in the selection task and the conditional inference task are summarised, and contrasted with the matching bias approach. It is argued that the probabilistic contrast class account provides a unified, rational explanation for effects across these tasks. Moreover, there are results that are only explained by the contrast class account that are also discussed. The only major anomaly is the explicit negations effect in the selection task (Evans, Clibbens, & Rood, 1996), which it is argued may not be the result of normal interpretative processes. It is concluded that the effects of negation on human reasoning provide good evidence for the view that human reasoning processes may be rational according to a probabilistic standard.     

On the construction and maintenance of expectancies

Reaction time techniques were used to examine the role of attention in the construction and maintenance of expectancies. In Experiment I, a primed letter matching task, expectancies were observed through a delay (cost) in responding to misprimed letter arrays. A secondary probe task was interpolated between prime and array letters on some of the trials, with attentional demands inferred from delayed responding to probes. By varying the amount of time between onset of the prime and either a probe or letter array, it was found that there is attentional involvement (as reflected in probe inhibition) prior to the observation of expectancies (as reflected in letter matching cost). It was also found that the interpolation of an attention-demanding probe task did not entirely disrupt primed expectancies. Experiment II found that an expectancy persists even when an interpolated distractor task signals that the expectancy is no longer valid. These expectancies were found to decay as a function of time. The implications of these results for attention allocation and memory activation views of expectancy were discussed.     

Deductive reasoning and matching-bias inhibition training: Evidence from a debiasing paradigm

Using the matching bias example, the aim of the present studies was to show that adults' reasoning biases are due to faulty executive inhibition programming. In the first study, the subjects were trained on Wason's classical card selection task; half were given training in how to inhibit the perceptual matching bias (experimental group) and half in logic without the inhibition component (control group). On the pre- and post-tests, their performance was assessed on the Evans conditional rule falsification task (with a negation in the antecedent of the rule), a task that also involves matching bias. In addition, subjects were tested for perceptual field dependence/independence using the Embedded Figures Test. The results brought out a specific inhibition training effect, as well as a clear-cut relationship in the experimental group between receptiveness to training and perceptual field independence. In the second study, the training paradigm was the same except that on the pre- and post-tests, the negation was in the consequent of the conditional rule (in this case, the perceptual matching response corresponds to the logical response). The subjects succeeded on the pre-test, and the matching-bias inhibition training had a negative effect on post-test performance. This specific negative priming effect confirms the inhibitory impact of our experimental training and outlines the dissociation of inhibition and logical components.     

Task related modulation of the motor system during language processing

Recent neurophysiological and brain imaging studies have shown that the motor system is involved in language processing. However, it is an open question whether this involvement is a necessary requisite to understand language or rather a side effect of distinct cognitive processes underlying it. In order to clarify this issue we carried out three behavioral experiments, using a go-no go paradigm. Italian verbs expressing hand actions, foot actions or an abstract content served as stimuli. Participants used their right hands to respond. In Experiment 1, in which a semantics decision task with an early delivery of the go signal (during processing language material) was used, slower responses were found for hand action-related verbs than for foot action-related verbs. In Experiment 2, using the same task with either an early or a delayed delivery of the go signal (when language material had been already processed), no difference was found between responses to the two verb categories in the delayed delivery condition. In Experiment 3, in which a lexical decision task with an early delivery of the go signal was used, again no difference between the two verb categories was found. The present findings demonstrate that during language processing the modulation of the motor system crucially occurs while performing a semantics decision task, thus supporting the notion that this involvement is a necessary step to understand language rather than a side effect of upstream cognitive processes.     

Directional bias in the mental representation of spatial events: nature or culture?

Previous research has shown a tendency for people to imagine simple sentences as evolving from left to right, with the sentence subject being located to the left of the object. In two cross-cultural studies comparing Italian and Arab participants, we investigated whether this bias is a function of hemispheric specialization or of directionality of written language (left to right in Italian, right to left in Arabic). Both studies found a reversal of directional bias in Arabs. Italians tended to position the subject to the left of the object, and Arabs tended to position the subject to the right of the object (Experiment 1); both groups were facilitated in a sentence-picture matching task when the subject was drawn in the position that it would usually occupy in the written language (left for Italians, right for Arabs; Experiment 2). In Experiment 2, an additional, language-independent facilitation was observed when action evolved from left to right, suggesting that both hemispheric specialization and scanning habit affect visual imaging.     

Response-repetition effects in task switching with and without response execution

Previous research into the mechanisms of task switching has shown that repeating the same response in a different task context is associated with costs. To investigate whether such response-repetition costs occur even when the first of the two responses is not overtly executed, we used a variant of the change-signal paradigm. Subjects responded to a first stimulus by pressing a left or right response key. In half of the trials, a second stimulus occurred after a variable, adaptively adjusted delay, indicating to abandon the first response, and only respond to the second stimulus using another set of left and right response keys. In Experiment 1, different tasks had to be performed with the first and second stimulus (task-switch condition); in Experiment 2, the same task had to be performed with both stimuli (task-repetition condition). Response-repetition costs were obtained in Experiment 1, and response-repetition benefits in Experiment 2. Importantly, these costs and benefits were obtained even when the first of the two responses had not been overtly executed. The data support the idea that interference of task-specific response codes occurs at the level of abstract response codes. Interference of such response codes occurs even when the responses are not overtly executed.     

Unconscious biases in task choices depend on conscious expectations

Recent studies highlight the influence of non-conscious information on task-set selection. However, it has not yet been tested whether this influence depends on conscious settings, as some theoretical models propose. In a series of three experiments, we explored whether non-conscious abstract cues could bias choices between a semantic and a perceptual task. In Experiment 1, we observed a non-conscious influence on task-set selection even when perceptual priming and cue-target compound confounds did not apply. Experiments 2 and 3 showed that, under restrictive conditions of visibility, cues only biased task selection when the conscious task-setting mindset led participants to search for information during the time period of the cue. However, this conscious strategy did not modulate the effect found when a subjective measure of consciousness was used. Altogether, our results show that the configuration of the conscious mindset determines the potential bias of non-conscious information on task-set selection.     

Matching bias in syllogistic reasoning: Evidence for a dual-process account from response times and confidence ratings

We examined matching bias in syllogistic reasoning by analysing response times, confidence ratings, and individual differences. Roberts’ (2005) “negations paradigm” was used to generate conflict between the surface features of problems and the logical status of conclusions. The experiment replicated matching bias effects in conclusion evaluation (Stupple & Waterhouse, 2009), revealing increased processing times for matching/logic “conflict problems”. Results paralleled chronometric evidence from the belief bias paradigm indicating that logic/belief conflict problems take longer to process than non-conflict problems (Stupple, Ball, Evans, & Kamal-Smith, 2011). Individuals’ response times for conflict problems also showed patterns of association with the degree of overall normative responding. Acceptance rates, response times, metacognitive confidence judgements, and individual differences all converged in supporting dual-process theory. This is noteworthy because dual-process predictions about heuristic/analytic conflict in syllogistic reasoning generalised from the belief bias paradigm to a situation where matching features of conclusions, rather than beliefs, were set in opposition to logic.     

Predicting and manipulating the incidence of inattentional blindness

Inattentional blindness (IB) occurs when an observer, who is engaged in a resource-consuming task, fails to notice an unexpected although salient stimulus appearing in their visual field. The incidence of IB is affected by changes in stimulus-driven properties, but little research has examined individual differences in IB propensity. We examine working memory capacity (WMC), processing styles (flicker task), inhibition (Stroop task), and training in predicting IB. WMC is associated with IB (Experiments 1 and 2) but neither processing style (Experiment 1) nor inhibition (Experiment 2) was associated. In Experiment 2, prior training on a task reduced the incidence of IB compared to no prior training, and this effect was significantly larger when trained on the same tracking task as that used in the IB task rather than a different task. We conclude that IB is related to WMC and that training can influence the incidence of IB.     

工作记忆的存储时间及目标时距对时间知觉的影响

本研究操作记忆信息与计时开始之间的时间间隔（ISI）和目标时距,探讨工作记忆影响时间判断的灵活性。被试首先记忆一个客体,然后在每个trial的最后判断测试刺激是否与记忆项相同;在延迟阶段,被试完成时间判断任务,即判断相继出现的两个刺激的时距哪个更长（或更短）。时间任务中的一个刺激与记忆内容完全相同,相应的另一个刺激与记忆内容在形状和颜色上都不同。重复条件下,被试忽略第一个刺激,仅完成时间判断任务。结果发现,时间间隔（ISI）短时,记忆匹配条件下的准确率更高,匹配刺激延长了知觉的时间;但随着时间间隔的增加,工作记忆匹配对时间判断的影响降低甚至消失。并且,长或短ISI,记忆任务或重复条件下,目标时距长时,记忆匹配反而缩短了知觉的时间。研究说明工作记忆对时间判断的影响是灵活的,受到注意或工作记忆等高级认知系统的调控。