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)

The pessimistic conclusion that people have relatively poor insight into the weighting schemes they use when they make holistic judgements has been generally accepted among judgement researchers. The empirical research that supported this generalisation rested on indices of self-insight that were produced directly by the subjects. It was often the case that subjects were unable to correctly name even the single most important factor influencing their decisions, as indicated by a mathematical model of their judgement schemes. Using an alternate method (...) of assessing self-insight, however, Reilly and Doherty found that subjects have far better self-insight than previously believed possible. The present paper employed the same methodology to investigate insight into the policy of another person as well as into oneself, and examined the relation of self-insight and other-insight to interpersonal conflict. Subjects were 50 dyads of university students. The results showed that: subjects exhibited the expected high levels of self-insight via the recognition procedure; subjects were able to identify the statistically generated policy of their roommate, thus exhibiting other-insight; the ability to identify one's own policy is somewhat related to the ability to articulate one's own policy that is, roommates with insight via recognition had higher indices of self-insight as measured by the traditional correlation method; subjects who were able to identify their own policy were more likely to identify their roommate's policy and individuals who possess self- and other-insight had less conflict in their roommate relationships. (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)

Intuitive predictions and judgements under uncertainty are often mediated by judgemental heuristics that sometimes lead to biases. Our micro-developmental study suggests that a presumption of rationality is justified for adult subjects, in so far as their systematic judgemental biases appear to be due to a specific executive-inhibition failure in working memory, and not necessarily to a lack of understanding of the fundamental principles of probability. This hypothesis was tested using an experimental procedure in which 60 adult subjects were trained to (...) inhibit the classical conjunction bias on a frequency judgement task derived from Tversky and Kahneman's work. Pre- and post-test performance was assessed via a probability judgement task. The data indicated a training effect, suggesting that subjects traditionally labelled as "irrational" with respect to the classical rules of inductive reasoning are in fact "inefficient inhibitors". These findings are discussed in terms of a polymorphous view of rationality. (shrink)

Four experiments investigated the effects of probability manipulations on the indicative four card selection task (Wason, 1966, 1968). All looked at the effects of high and low probability antecedents (p) and consequents (q) on participants' data selections when determining the truth or falsity of a conditional rule, if p then q . Experiments 1 and 2 also manipulated believability. In Experiment 1, 128 participants performed the task using rules with varied contents pretested for probability of occurrence. Probabilistic effects were observed (...) which were partly consistent with some probabilistic accounts but not with non-probabilistic approaches to selection task performance. No effects of believability were observed, a finding replicated in Experiment 2 which used 80 participants with standardised and familiar contents. Some effects in this experiment appeared inconsistent with existing probabilistic approaches. To avoid possible effects of content, Experiments 3 (48 participants) and 4 (20 participants) used abstract material. Both experiments revealed probabilistic effects. In the Discussion we examine the compatibility of these results with the various models of selection task performance. (shrink)

Samuels and Stich explore the debate over the extent to which ordinary human reasoning and decision making is rational. One prominent cluster of views, often associated with the heuristics and biases tradition in psychology, maintains that human reasoning is, in important respects, normatively problematic or irrational. Samuels and Stich start by sketching some key experimental findings from this tradition and describe a range of pessimistic claims about the rationality of ordinary people that these and related findings are sometimes taken to (...) support. Such pessimistic interpretations of the experimental findings have not gone unchallenged however: Samuels and Stich outline some of the research on reasoning that has been done by evolutionary psychologists and sketch a cluster of more optimistic theses about ordinary reasoning that such psychologists defend. Although Samuels and Stich think that the most dire pronouncements made by writers in the heuristics and biases tradition are unwarranted, they also maintain that the situation is rather more pessimistic than sometimes suggested by evolutionary psychologists. They conclude by defending this “middle way” and sketch a family of “dual processing” theories of reasoning which, they argue, offer some support for the moderate interpretation they advocate. (shrink)

With the rapid development of the Internet and the normalization of COVID-19 epidemic prevention and control, Online health communities have gradually become one of the important ways for people to obtain health information, and users have to go through a series of information processing when facing the massive amount of data. Understanding the factors influencing user information processing is necessary to promote users’ health literacy, health knowledge popularization and health behavior shaping. Based on the Heuristic-Systematic Model, Information Ecology Theory, Privacy (...) Trade-Off and Self-Efficacy Theory, we constructed a model of factors influencing user information processing in online health communities. We found that information quality and emotional support had indirect effects on heuristic and systematic information processing, and these effects were mediated by privacy concerns and self-efficacy. In our research model, systematic information processing was most positively influenced directly by self-efficacy. Privacy concerns had a direct negative correlation with both dual information processing pathways. Therefore, OHCs managers should develop relevant regulations to ensure the information quality in OHCs and improve privacy protection services to promote user information processing by improving users’ self-efficacy and reducing their privacy concerns. Providing a user-friendly and interactive environment for users is also recommended to create more emotional support, thus facilitating more systematic information processing. (shrink)

I present a critical discussion of dual-process theories of reasoning and decision making with particular attention to the nature and role of Type 2 processes. The original theory proposed...

Human decision making shows systematic simplifications and deviations from the tenets of rationality (‘heuristics’) that may lead to suboptimal decisional outcomes (‘cognitive biases’). There are currently three prevailing theoretical perspectives on the origin of heuristics and cognitive biases: a cognitive-psychological, an ecological and an evolutionary perspective. However, these perspectives are mainly descriptive and none of them provides an overall explanatory framework for the underlying mechanisms of cognitive biases. To enhance our understanding of cognitive heuristics and biases we propose a neural (...) network framework for cognitive biases, which explains why our brain systematically tends to default to heuristic (‘Type 1’) decision making. We argue that many cognitive biases arise from intrinsic brain mechanisms that are fundamental for the working of biological neural networks. In order to substantiate our viewpoint, we discern and explain four basic neural network principles: (1) Association, (2) Compatibility (3) Retainment, and (4) Focus. These principles are inherent to (all) neural networks which were originally optimized to perform concrete biological, perceptual, and motor functions. They form the basis for our inclinations to associate and combine (unrelated) information, to prioritize information that is compatible with our present state (such as knowledge, opinions and expectations), to retain given information that sometimes could better be ignored, and to focus on dominant information while ignoring relevant information that is not directly activated. The supposed mechanisms are complementary and not mutually exclusive. For different cognitive biases they may all contribute in varying degrees to distortion of information. The present viewpoint not only complements the earlier three viewpoints, but also provides a unifying and binding framework for many cognitive bias phenomena. (shrink)

In this article, we explore the implications of opposing domains theory for developing ethical leaders. Opposing domains theory highlights a neurological tension between analytic reasoning and socioemotional reasoning. Specifically, when we engage in analytic reasoning, we suppress our ability to engage in socioemotional reasoning and vice versa. In this article, we bring together the domains of neuroscience, psychology, and ethics, to inform our theorizing around ethical leadership. We propose that a key issue for ethical leadership is achieving a healthy balance (...) between analytic reasoning and socioemotional reasoning. We argue that organizational culture often encourages too heavy a reliance on nonemotional forms of reasoning to arrive at moral judgments. As a result, leaders run the risk of suppressing their ability to pay attention to the human side of moral dilemmas and, in doing so, dehumanize colleagues, particularly subordinates, and clients. (shrink)

Cognitive scientists have revealed systematic errors in human reasoning. There is disagreement about what these errors indicate about human rationality, but one upshot seems clear: human reasoning does not seem to fit traditional views of human rationality. This concern about rationality has made its way through various fields and has recently caught the attention of philosophers. The concern is that if philosophers are prone to systematic errors in reasoning, then the integrity of philosophy would be threatened. In this paper, I (...) present some of the more famous work in cognitive science that has marshaled this concern. Then I present reasons to think that those with training in philosophy will be less prone to certain systematic errors in reasoning. The suggestion is that if philosophers could be shown to be less prone to such errors, then the worries about the integrity of philosophy could be constrained. Then I present evidence that, according to performance on the CRT (Frederick 2005), those who have benefited from training and selection in philosophy are indeed less prone to one kind of systematic error: irrationally arbitrating between intuitive and reflective responses. Nonetheless, philosophers are not entirely immune to this systematic error, and their proclivity for this error is statistically related to their responses to a variety of philosophical questions. So, while the evidence herein puts constraints on the worries about the integrity of philosophy, it by no means eliminates these worries. The conclusion, then, is that the present evidence offers prima facie reasons to ascribe a mitigated privilege to philosophers' ability to rationally arbitrate between intuitive and reflective responses. (shrink)

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. (shrink)

This study investigated individual differences in the belief bias effect, which is the tendency to accept conclusions because they are believable rather than because they are logically valid. It was observed that the extent of an individual's belief bias effect was unrelated to a number of measures of reasoning competence. Instead, as predicted by mental models theory, it was related to a person's ability to generate alternative representations of premises: the more alternatives a person generated, the less likely they were (...) to show a belief bias effect. In contrast to belief effects, which were predicted by the number of alternatives generated, scores on logical reasoning tasks were predicted by an individual's understanding of the concept of logical necessity. These two mediating variables, ability to generate alternatives and understanding of logical necessity, were themselves predicted by similar variables, such as cognitive motivation and abstract reasoning ability. Our findings strongly support the mental models interpretation of the belief bias effect, and suggest that individual differences in this effect are associated with a specific ability to generate alternatives, rather than with a general logical competence. (shrink)

Johnson-Laird and Byrne present a theory of conditional inference based upon the manipulation of mental models. In the present paper, the theory is critically examined with regard to its ability to account for psychological data, principally with respect to the rate at which people draw the four basic inferences of modus ponens, denial of the antecedent, affirmation of the consequent and modus tollens. It is argued first that the theory is unclear in its definition and in particular with regard to (...) predictions of problem difficulty. Clarification and specification of principles are consequently provided here. Next, it is argued that there are a number of phenomena in the conditional reasoning literature for which the theory cannot account in its present form. Specifically, the relatively frequency of DA and AC inferences on affirmative conditionals is not as predicted by the theory, differences occur between inferences on if then and only if rules beyond the capacity of the theory to explain and there is no account of the “negative conclusion bias” observed when negated components are introduced into the rules. A number of revisions to the mental model theory of conditional reasoning are proposed in order to account for these findings. (shrink)

It has been distinguished between unified cognitive architecture and multiple-process architecture. Based on this distinction, we will try to show that if processes coordination criteria are explicated and analyzed, double-process theories for reasoning and decision making have difficulties to consolidate as multiple process architecture.

Four experiments assessed the relative involvement of different working memory components in two types of reasoning tasks: propositional and spatial reasoning. Using the secondary-task methodology, visual, central-executive, and phonological loads were realised. Although the involvement of visuospatial resources in propositional reasoning has traditionally been considered to be small, an overall analysis of the present data suggests an alternative account. A theoretical analysis of the pattern of results in terms of Evans' (1984, 1989) twostage theory of reasoning is proposed and tested (...) in Experiments 3 and 4, in which direct evidence for the alternative account was obtained: significant disruption of propositional reasoning by a concurrent spatial load. (shrink)

Natural myside bias is the tendency to evaluate propositions from within one's own perspective when given no instructions or cues (such as within-participants conditions) to avoid doing so. We defined the participant's perspective as their previously existing status on four variables: their sex, whether they smoked, their alcohol consumption, and the strength of their religious beliefs. Participants then evaluated a contentious but ultimately factual proposition relevant to each of these demographic factors. Myside bias is defined between-participants as the mean difference (...) in the evaluation of the proposition between groups with differing prior status on the variable. Whether an individual difference variable (such as cognitive ability) is related to the magnitude of the myside bias is indicated by whether the individual difference variable interacts with the between-participants status variable. In two experiments involving a total of over 1400 university students ( n = 1484) and eight different comparisons, we found very little evidence that participants of higher cognitive ability displayed less natural myside bias. The degree of myside bias was also relatively independent of individual differences in thinking dispositions. We speculate that ideas from memetic theory and dual-process theory might help to explain why natural myside bias is quite dissociated from individual difference variables. (shrink)

Cooperation admits of degrees. When factory workers stage a slowdown, they do not cease to cooperate with management in the production of goods altogether, but they are not fully cooperative either. Full cooperation implies that participants in a joint action are committed to rendering appropriate contributions as needed toward their joint end so as to bring it about, consistently with the type of action and the generally agreed upon constraints within which they work, as efficiently as they can, where their (...) contributions are sensitive to information (where available) about how others are contributing in the sense that they adjust as needed their contributions in light of information about how others are contributing to ensure effective pursuit of their joint end, where this includes rendering aid to other participants if needed, insofar as they are able. Full cooperation entails those cooperating are engaged in a joint intentional action. Some prominent studies of joint intentional action focus exclusively on cases of full cooperation (notably that of Michael Bratman (2014)). But not all joint intentional action is fully cooperative. One example is the work slowdown. Another example is provided by competitive games like chess and football, or sports like boxing and wrestling, where participants are clearly not intending to contribute to the pursuit of all of the goals of the others engaged in the activity, even when those goals are internal to the type of activity in question, but instead intend actively to frustrate some of them. In this paper, I provide a taxonomy of forms of non-cooperative behavior within the context of behavior that is still to some degree cooperative, and I argue that the minimal conditions of joint intentional action define minimal cooperative behavior, that is, that minimally joint intentional action is per se minimally cooperative behavior. I define in precise terms what that comes to, and how it is possible in cases in which it seems that one or more participants are in one or more ways acting so as to frustrate the contributions of other participants to their joint action. (shrink)

The study of ethical decision-making has made significant advances, particularly with regard to the ways in which different types of processing are implicated. In recent decades, much of this advancement has been driven by the influence of dual-process theories of cognition. Unfortunately, the wealth of findings in this context can be confusing for management scholars and practitioners who desire to know how best to encourage ethical behavior. While some studies suggest that deliberate reflection leads to more ethical behavior, other studies (...) find, in contrast, that intuitive decision-making leads to more ethical results. The goal of this integrative conceptual review is to help make sense of such apparently contradictory findings by identifying the moderating influences that lead to more versus less ethical decisions, whether they are made via intuitive or deliberative processes. Based on our integrative review of moderators from different disciplines and eras, we develop a taxonomy that can aid researchers in the task of identifying when similar constructs have been studied under different names. We organize our findings concerning these influences in accordance with four emergent moderator categories—psychological, situational, social, and physiological. This work helps us identify patterns of moderating factors across both intuitive and deliberative ethical decision-making, gaps that suggest future research directions and practical implications. (shrink)

_Background:_ Cognitive biases play an important role in the formation and maintenance of delusions. These biases are indicators of a weak reflective mind, or reduced engaging in reflective and deliberate reasoning. In three experiments, we tested whether a bias to accept non-sense statements as profound, treat metaphorical statements as literal, and suppress intuitive responses is related to psychotic-like experiences. _Methods:_ We tested deliberate reasoning and psychotic-like experiences in the general population and in patients with a former psychotic episode. Deliberate reasoning (...) was assessed with the bullshit receptivity scale, the ontological confabulation scale and the cognitive reflection test (CRT). We also measured algorithmic performance with the Berlin numeracy test and the wordsum test. Psychotic-like experiences were measured with the Community Assessment of Psychic Experience (CAPE-42) scale. _Results:_ Psychotic-like experiences were positively correlated with a larger receptivity toward bullshit, more ontological confabulations, and also a lower score on the CRT but not with algorithmic task performance. In the patient group higher psychotic-like experiences significantly correlated with higher bullshit receptivity. _Conclusion:_ Reduced deliberate reasoning may contribute to the formation of delusions, and be a general thinking bias largely independent of a person's general intelligence. Acceptance of bullshit may be facilitated the more positive symptoms a patient has, contributing to the maintenance of the delusions. (shrink)

A survey of contemporary philosophical and scientific literatures reveals that different authors employ the term ‘heuristic’ in ways that deviate from, and are sometimes inconsistent with, one another. Given its widespread use in philosophy and cognitive science generally, it is striking that there appears to be little concern for a clear account of what phenomena heuristics pick out or refer to. In response, I consider several accounts of ‘heuristic’, and I draw a number of distinctions between different sorts of heuristics (...) in order to make sense of various research programmes. I then develop a working characterization of ‘heuristic’ which is shown to be coherent and robust enough to serve as a kind within philosophy and cognitive science broadly. My intent is not to pursue a unified account of ‘heuristic’, but to highlight some features of certain kinds of heuristics that are important for theorizing about cognition in order to proceed with a science of the mind/brain. 1 Why We Need an Appropriate Characterization of ‘Heuristic’2 Inadequate Definitions2.1 A positive attempt2.2 Heuristics versus guaranteed correct outcomes3 A Taxonomy of Heuristics3.1 Stimulus-driven versus heuristic3.2 Perceptual versus cognitive heuristics3.3 Computational versus cognitive heuristics3.4 Methodological versus inferential heuristics3.5 Summary of distinctions4 Characterizing Cognitive Heuristics4.1 Heuristics as rules of thumb4.2 Beyond rules of thumb: exploiting information5 Concluding Remarks. (shrink)

To successfully learn using open Internet resources, students must be able to critically search, evaluate and select online information, and verify sources. Defined as critical online reasoning, this construct is operationalized on two levels in our study: the student level using the newly developed Critical Online Reasoning Assessment, and the online information processing level using event log data, including gaze durations and fixations. The written responses of 32 students for one CORA task were scored by three independent raters. The resulting (...) score was operationalized as “task performance,” whereas the gaze fixations and durations were defined as indicators of “process performance.” Following a person-oriented approach, we conducted a process mining analysis, as well as a latent class analysis to test whether—following the dual-process theory—the undergraduates could be distinguished into two groups based on both their process and task performance. Using PM, the process performance of all 32 students was visualized and compared, indicating two distinct response process patterns. One group of students, defined as “strategic information processers,” processed online information more comprehensively, as well as more efficiently, which was also reflected in their higher task scores. In contrast, the distributions of the process performance variables for the other group, defined as “avoidance information processers,” indicated a poorer process performance, which was also reflected in their lower task scores. In the LCA, where two student groups were empirically distinguished by combining the process performance indicators and the task score as a joint discriminant criterion, we confirmed these two COR profiles, which were reflected in high vs. low process and task performances. The estimated parameters indicated that high-performing students were significantly more efficient at conducting strategic information processing, as reflected in their higher process performance. These findings are so far based on quantitative analyses using event log data. To enable a more differentiated analysis of students’ visual attention dynamics, more in-depth qualitative research of the identified student profiles in terms of COR will be required. (shrink)

A filosofia da mente contemporânea, como grande parte da ciência cognitiva, favorece concepções austeras da mente, que buscam explicar a natureza do fenômeno mental a partir de um pequeno conjunto de princípios básicos. Psicologia associacionista, behaviorismo, teorias computacionais e teorias conexionistas da mente são visões deste tipo. Contra elas, argumento que não só a complexidade do fenômeno mental é tal que nenhuma teoria geral deste tipo pode ser possível, mas também que para cada tipo de fenômeno mental um tipo específico (...) de teoria pode ser necessário. Advogo uma concepção da mente como formada por camadas, composta por um número de níveis distintos , cada uma tendo seus princípios específicos e tipo de complexidade. Esse modelo é ilustrado na noção de crença, que compreende vários níveis de complexidade e uma hierarquia estrutural. Concepções dualistas da cognição superior servem como base para este modelo multi-nível. (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)

Individual differences on a variety of framing and conjunction problems were examined in light of Slovic and Tversky's (1974) understanding/acceptance principle-that more reflective and skilled reasoners are more likely to affirm the axioms that define normative reasoning and to endorse the task construals of informed experts. The predictions derived from the principle were confirmed for the much discussed framing effect in the Disease Problem and for the conjunction fallacy on the Linda Problem. Subjects of higher cognitive ability were disproportionately likely (...) to avoid each fallacy. Other framing problems produced much more modest levels of empirical support. It is conjectured that the varying patterns of individual differences are best explained by two-process theories of reasoning (e.g. Evans, 1984, 1996; Sloman, 1996) conjoined with the assumption that the two processes differentially reflect interactional and analytic intelligence. (shrink)

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. (shrink)

The phenomenon known as matching bias consists of a tendency to see cases as relevant in logical reasoning tasks when the lexical content of a case matches that of a propositional rule, normally a conditional, which applies to that case. Matching is demonstrated by use of the negations paradigm that is by using conditionals in which the presence and absence of negative components is systematically varied. The phenomenon was first published in 1972 and the present paper reviews the history of (...) research and theorising on the problem in the subsequent 25 years. Theories of matching bias considered include those based on several broad frameworks including the heuristic-analytic theory, the mental models theory, the theory of optimal data selection, and relevance theory as well as the specific processing-negations account. The ability of these theories to account for a range of phenomena is considered, including the effects of linguistic form, realistic content, and explicit negation on the matching bias effect. Of particular importance are recent findings showing that the bias is observable on a wider range of linguistic forms than has generally been thought, and that it is almost entirely dependent on the use of implicit negation in the logical cases to which rules are applied. The reasons for the general suppression of matching when realistic content is used are, however, unclear and a need for further research is identified here. It is concluded that matching bias is a highly robust effect which is closely connected with the problem of understanding implicit negation. Most of the theories in the literature are unable to account for at least some of the major phenomena discovered in research on the bias. The accounts that fare best are those that posit local effects of negation, including the heuristic-analytic and processing negations theories. (shrink)