Reason, we are told, is what makes us human, the source of our knowledge and wisdom. If reason is so useful, why didn't it also evolve in other animals? If reason is that reliable, why do we produce so much thoroughly reasoned nonsense? In their groundbreaking account of the evolution and workings of reason, Hugo Mercier and Dan Sperber set out to solve this double enigma. Reason, they argue with a compelling mix of real-life and experimental evidence, is not geared (...) to solitary use, to arriving at better beliefs and decisions on our own. What reason does, rather, is help us justify our beliefs and actions to others, convince them through argumentation, and evaluate the justifications and arguments that others address to us. In other words, reason helps humans better exploit their uniquely rich social environment. This interactionist interpretation explains why reason may have evolved and how it fits with other cognitive mechanisms. It makes sense of strengths and weaknesses that have long puzzled philosophers and psychologists--why reason is biased in favor of what we already believe, why it may lead to terrible ideas and yet is indispensable to spreading good ones.--. (shrink)

Humans massively depend on communication with others, but this leaves them open to the risk of being accidentally or intentionally misinformed. To ensure that, despite this risk, communication remains advantageous, humans have, we claim, a suite of cognitive mechanisms for epistemic vigilance. Here we outline this claim and consider some of the ways in which epistemic vigilance works in mental and social life by surveying issues, research and theories in different domains of philosophy, linguistics, cognitive psychology and the social sciences.

Much evidence has accumulated in favor of such a dual view of reasoning. There is however some vagueness in the way the two systems are characterized. Instead of a principled distinction, we are presented with a bundle of contrasting features - slow/fast, automatic/controlled, explicit/implicit, associationist/rule based, modular/central - that, depending on the specific dual process theory, are attributed more or less exclusively to one of the two systems. As Evans states in a recent review, “it would then be helpful to (...) have some clear basis for this distinction”; he also suggests that “we might be better off talking about type 1 and type 2 processes” rather than systems. We share the intuitions that drove the development of dual system theories. Our goal here is to propose in the same spirit a principled distinction between two types of inferences: ‘intuitive inference’ and ‘reflective inference’. We ground this distinction in a massively modular view of the human mind where metarepresentational modules play an important role in explaining the peculiarities of human psychological evolution. We defend the hypothesis that the main function of reflective inference is to produce and evaluate arguments occurring in interpersonal communication. This function, we claim, helps explain important aspects of reasoning. We review some of the existing evidence and argue that it gives support to this approach. (shrink)

According to the argumentative theory of reasoning, humans have evolved reasoning abilities for argumentative purposes. This implies that some reasoning skills should be universals. Such a claim seems to be at odd with findings from cross-cultural research. First, a wealth of research, following the work of Luria, has shown apparent difficulties for illiterate populations to solve simple but abstract syllogisms. It can be shown, however, that once they are willing to accept the pragmatics of the task, these participants can perform (...) at or near ceiling. Second, historical, sociological and anthropological research has been used to claim that some Eastern cultures have not developed argumentation. These claims are the result of oversimplifications and of a selective view of the data. A closer looks reveals instead very elaborate forms of argumentation, in Chinese culture particularly. Third, cross-cultural psychologists have carried out an extensive research program aimed at showing that Easterners do not rely on the principle of non-contradiction and that they use holistic rather than analytic thinking. A review of these experiments shows that no qualitative difference emerges in the way Easterners and Westerners deal with argumentation and that in the proper context both populations can easily have recourse to holistic or analytic thinking. It is possible to conclude from this critical review that the reasoning skills involved in argumentation seem to be universal even though they can be used in different ways in various cultural contexts. (shrink)

Theoreticians of deliberative democracy have sometimes found it hard to relate to the seemingly contradictory experimental results produced by psychologists and political scientists. We suggest that this problem may be alleviated by inserting a layer of psychological theory between the empirical results and the normative political theory. In particular, we expose the argumentative theory of reasoning that makes the observed pattern of findings more coherent. According to this theory, individual reasoning mechanisms work best when used to produce and evaluate arguments (...) during a public deliberation. It predicts that when diverse opinions are discussed, group reasoning will outperform individual reasoning. It also predicts that individuals have a strong confirmation bias. When people reason either alone or with like-minded peers, this confirmation bias leads them to reinforce their initial attitudes, explaining individual and group polarization. We suggest that the failures of reasoning are most likely to be remedied at the collective than at the individual level. (shrink)

The role of reasoning in our moral lives has been increasingly called into question by moral psychology. Not only are intuitions guiding many of our moral judgments and decisions, with reasoning only finding post-hoc rationalizations, but reasoning can sometimes play a negative role, by finding excuses for our moral violations. The observations fit well with the argumentative theory of reasoning (Mercier H, Sperber D, Behav Brain Sci, in press-b), which claims that reasoning evolved to find and evaluate arguments in dialogic (...) contexts. This theory explains the strong confirmation bias that reasoning displays when it produces arguments, which in turn explains its tendency to rationalize our decisions. But this theory also predicts that people should be able to evaluate arguments felicitously and that, as a result, people should reason better in groups, when they are confronted with other people’s arguments. Groups are able to converge on better moral judgments. It is argued that reasoning and argumentation play an important role in our everyday moral lives, and a defense of the value of reasoning for moral change is offered. (shrink)

Reasoning research suggests that people use more stringent criteria when they evaluate others' arguments than when they produce arguments themselves. To demonstrate this “selective laziness,” we used a choice blindness manipulation. In two experiments, participants had to produce a series of arguments in response to reasoning problems, and they were then asked to evaluate other people's arguments about the same problems. Unknown to the participants, in one of the trials, they were presented with their own argument as if it was (...) someone else's. Among those participants who accepted the manipulation and thus thought they were evaluating someone else's argument, more than half rejected the arguments that were in fact their own. Moreover, participants were more likely to reject their own arguments for invalid than for valid answers. This demonstrates that people are more critical of other people's arguments than of their own, without being overly critical: They are better able to tell valid from invalid arguments when the arguments are someone else's rather than their own. (shrink)

Reasoning, defined as the production and evaluation of reasons, is a central process in science. The dominant view of reasoning, both in the psychology of reasoning and in the psychology of science, is of a mechanism with an asocial function: bettering the beliefs of the lone reasoner. Many observations, however, are difficult to reconcile with this view of reasoning; in particular, reasoning systematically searches for reasons that support the reasoner’s initial beliefs, and it only evaluates these reasons cursorily. By contrast, (...) reasoners are well able to evaluate others’ reasons: accepting strong arguments and rejecting weak ones. The argumentative theory of reasoning accounts for these traits of reasoning by postulating that the evolved function of reasoning is to argue: to find arguments to convince others and to change one’s mind when confronted with good arguments. Scientific reasoning, however, is often described as being at odds with such an argumentative mechanisms: scientists are supposed to reason objectively on their own, and to be pigheaded when their theories are challenged, even by good arguments. In this article, we review evidence showing that scientists, when reasoning, are subject to the same biases as are lay people while being able to change their mind when confronted with good arguments. We conclude that the argumentative theory of reasoning explains well key features of scientists’ reasoning and that differences in the way scientists and laypeople reason result from the institutional framework of science. (shrink)

Having defended the usefulness of our definition of reasoning, we stress that reasoning is not only for convincing but also for evaluating arguments, and that as such it has an epistemic function. We defend the evidence supporting the theory against several challenges: People are good informal arguers, they reason better in groups, and they have a confirmation bias. Finally, we consider possible extensions, first in terms of process-level theories of reasoning, and second in the effects of reasoning outside the lab.

By systematically biasing our beliefs, self-deception can endanger our ability to successfully convey our messages. It can also lead lies to degenerate into more severe damages in relationships. Accordingly, I suggest that the biases reviewed in the target article do not aim at self-deception but instead are the by-products of several other mechanisms: our natural tendency to self-enhance, the confirmation bias inherent in reasoning, and the lack of access to our unconscious minds.

Often, when several norms are present and may be in conflict, individuals will display a self-serving bias, privileging the norm that best serves their interests. Xiao and Bicchieri (J Econ Psychol 31(3):456–470, 2010) tested the effects of inequality on reciprocating behavior in trust games and showed that—when inequality increases—reciprocity loses its appeal. They hypothesized that self-serving biases in choosing to privilege a particular social norm occur when the choice of that norm is publicly justifiable as reasonable, even if not optimal (...) for one of the parties. In line with the literature on motivated reasoning, this justification should find some degree of support among third parties. The results of our experimental survey of third parties support the hypothesis that biases are not always unilateral selfish assessments. Instead, they occur when the choice to favor a particular norm is supported by a shared sense that it is a reasonable and justifiable choice. (shrink)

Much work on intellectual humility has focused on its epistemic benefits. We suggest that displaying (or failing to display) intellectual humility also has effects on how others perceive us and that, as a result, intellectual humility can serve reputation management purposes, in at least four ways: (i) Intellectual humility can be used to signal we are a good source of information; (ii) Intellectual humility can be used to signal we are competent through countersignaling; (iii) Intellectual humility can be used to (...) make sure others do not believe we are overclaiming superiority; (iv) lack of intellectual humility (or intellectual arrogance) can be used to signal dominance. The evidence suggests that intellectual humility (or lack thereof) can have each of these effects. Seeing intellectual humility as (inter alia) a reputation management tool predicts that people will be more or less likely to display intellectual humility in some contexts. For instance, people in a position of power might stand to lose less if they fail to be intellectual humble; accordingly, evidence suggests that they tend to display less intellectual humility. In conclusion, we speculate that understanding intellectual humility as reputation management could help construct environments more conducive to displays of intellectual humility. (shrink)

Expert reasoning is responsible for some of the most stunning human achievements, but also for some of the most disastrous decisions ever made. The argumentative theory of reasoning has proven very effective at explaining the pattern of reasoning’s successes and failures. In the present article, it is expanded to account for expert reasoning. The argumentative theory predicts that reasoning should display a strong confirmation bias. If argument quality is not sufficiently high in a domain, the confirmation bias will make experts (...) tap into their vast knowledge to defend whatever opinion they hold, with polarization and overconfidence as expected results. By contrast, experts should benefit even more from the power of group discussion to make the best of the confirmation bias—when they genuinely disagree that is, otherwise polarization is again likely to ensue. When experts interact with laymen other mechanisms can take the lead, in particular trust calibration and consistency checking. They can yield poor outcomes if experts do not have a sustained interaction with laymen, or if the laymen have strong opinions when they witness a debate between experts. Seeing reasoning as a mechanism of epistemic vigilance aimed at finding and evaluating arguments helps make better sense of expert reasoning performance, be it in individual ratiocination, in debates with other experts, or in interactions with laymen. (shrink)

Many fields of study have shown that group discussion generally improves reasoning performance for a wide range of tasks. This article shows that most of the population, including specialists, does not expect group discussion to be as beneficial as it is. Six studies asked participants to solve a standard reasoning problem—the Wason selection task—and to estimate the performance of individuals working alone and in groups. We tested samples of U.S., Indian, and Japanese participants, European managers, and psychologists of reasoning. Every (...) sample underestimated the improvement yielded by group discussion. They did so even after they had been explained the correct answer, or after they had had to solve the problem in groups. These mistaken intuitions could prevent individuals from making the best of institutions that rely on group discussion, from collaborative learning and work teams to deliberative assemblies. (shrink)

Because reasoning allows us to justify our beliefs and evaluate these justifications it is central to folk epistemology. Following Sperber, and contrary to classical views, it will be argued that reasoning evolved not to complement individual cognition but as an argumentative device. This hypothesis is more consistent with the prevalence of the confirmation and disconfirmation biases. It will be suggested that these biases render the individual use of reasoning hazardous, but that when reasoning is used in its natural, argumentative, context (...) they can represent a smart way to divide labor without loosing epistemic value. (shrink)

Are we gullible? Can we be easily influenced by what others tell us, even if they do not deserve our trust? Many strands of research, from social psychology to cultural evolution suggest that humans are by nature conformist and eager to follow prestigious leaders. By contrast, an evolutionary perspective suggests that humans should be vigilant towards communicated information, so as not to be misled too often. Work in experimental psychology shows that humans are equipped with sophisticated mechanisms that allow them (...) to carefully evaluate communicated information. These open vigilance mechanisms lead us to reject messages that clash with our prior beliefs, unless the source of the message has earned our trust, or provides good arguments, in which case we can adaptively change our minds. These mechanisms make us largely immune to mass persuasion, explaining why propaganda, political campaigns, advertising, and other attempts at persuading large groups nearly always fall in deaf ears. However, some false beliefs manage to spread through communication. I argue that most popular false beliefs are held reflectively, which means that they have little effect on our thoughts and behaviors, and that many false beliefs can be socially beneficial. Accepting such beliefs thus reflects a much weaker failure in our evaluation of communicated information than might at first appear. (shrink)

Peng and Nisbett put forward an influential theory of the influence of culture on the resolution of contradiction. They suggested that Easterners deal with contradiction in a dialectical manner, trying to reconcile opposite points of view and seeking a middle-way. Westerners, by contrast, would follow the law of excluded middle, judging one side of the contradiction to be right and the other to be wrong. However, their work has already been questioned, both in terms of replicability and external validity. Here (...) we test alternative interpretations of two of Peng and Nisbett’s experiments and conduct a new test of their theory in a third experiment. Overall, the Eastern and Western participants behaved similarly, failing to exhibit the cross-cultural differences observed by Peng and Nisbett. Several interpretations of these failed replications and this failed new test are suggested. Together with previous failed replications, the present results raise questions about the breadth of Peng and Nisbett’s interpretation of cross-cultural differences in dealing with contradiction. (shrink)

Coherence plays an important role in psychology. In this article, I suggest that coherence takes two main forms in humans’ cognitive system. The first belong to ‘system 1’. It relies on the degree of coherence between different representations to regulate them, without coherence being represented. By contrast other mechanisms, belonging to system 2, allow humans to represent the degree of coherence between different representations and to draw inferences from it. It is suggested that the mechanisms of explicit coherence evaluation have (...) social functions. They are used as means of epistemic vigilance—to evaluate what other people tell us. They can also be turned inwards to examine the coherence of our own beliefs. Their function is then to minimize the chances that we are perceived as being incoherent. Evidence from different domains of psychology is briefly reviewed in support of these hypotheses. (shrink)

Abstract How do people find arguments while engaged in a discussion? Following an analogy with visual search, a mechanism that performs this task is described. It is a metarepresentational device that examines representations in a mostly serial manner until it finds a good enough argument supporting one’s position. It is argued that the mechanism described in dual process theories as ‘system 2’, or analytic reasoning fulfills these requirements. This provides support for the hypothesis that reasoning serves an argumentative function. Content (...) Type Journal Article Pages 1-20 DOI 10.1007/s10503-011-9256-1 Authors Hugo Mercier, Philosophy, Politics and Economics Program, University of Pennsylvania, 313 Cohen Hall, 249 South 36th Street, Philadelphia, PA 19104, USA Journal Argumentation Online ISSN 1572-8374 Print ISSN 0920-427X. (shrink)

We elaborate on the approach to syllogistic reasoning based on “case identification” (Stenning & Oberlander, 1995; Stenning & Yule, 1997). It is shown that this can be viewed as the formalisation of a method of proof that dates back to Aristotle, namely proof by exposition ( ecthesis ), and that there are traces of this method in the strategies described by a number of psychologists, from St rring (1908) to the present day. We hypothesised that by rendering individual cases explicit (...) in the premises, the chance that reasoners would engage in a proof by exposition would be enhanced, and thus performance improved. To do so, we used syllogisms with singular premises (e.g., this X is Y ). This resulted in a uniform increase in performance as compared to performance on the associated standard syllogisms. These results cannot be explained by the main theories of syllogistic reasoning in their current state. (shrink)

In “Mercier and Sperber’s Argumentative Theory of Reasoning: From Psychology of Reasoning to Argumentation Studies” (2012) Santibáñez Yañez offers constructive comments and criticisms of the argumentative theory of reasoning. The purpose of this reply is twofold. First, it seeks to clarify two points broached by Yanez: (1) the relation between reasoning (in this specific theory) and dual process accounts in general and (2) the benefits that can be derived from reasoning and argumentation (again, in this specific theory). Second, it suggests (...) one domain—the categorization of arguments—in which argumentation studies and the argumentative theory of reasoning could usefully complement each other to yield a better understanding of the processes of argumentation. (shrink)

Reasoning is generally seen as a means to improve knowledge and make better decisions. However, much evidence shows that reasoning often leads to epistemic distortions and poor decisions. This suggests that the function of reasoning should be rethought. Our hypothesis is that the function of reasoning is argumentative. It is to devise and evaluate arguments intended to persuade. Reasoning so conceived is adaptive given the exceptional dependence of humans on communication and their vulnerability to misinformation. A wide range of evidence (...) in the psychology of reasoning and decision making can be reinterpreted and better explained in the light of this hypothesis. Poor performance in standard reasoning tasks is explained by the lack of argumentative context. When the same problems are placed in a proper argumentative setting, people turn out to be skilled arguers. Skilled arguers, however, are not after the truth but after arguments supporting their views. This explains the notorious confirmation bias. This bias is apparent not only when people are actually arguing, but also when they are reasoning proactively from the perspective of having to defend their opinions. Reasoning so motivated can distort evaluations and attitudes and allow erroneous beliefs to persist. Proactively used reasoning also favors decisions that are easy to justify but not necessarily better. In all these instances traditionally described as failures or flaws, reasoning does exactly what can be expected of an argumentative device: Look for arguments that support a given conclusion, and, ceteris paribus, favor conclusions for which arguments can be found. (shrink)

Developmental research suggests that young children tend to value dominant individuals over subordinates. This research, however, has nearly exclusively been carried out in Western cultures, and cross-cultural research among adults has revealed cultural differences in the valuing of dominance. In particular, it seems that Japanese culture, relative to many Western cultures, values dominance less. We conducted two experiments to test whether this difference would be observed in preschoolers. In Experiment 1, preschoolers in France and in Japan were asked to identify (...) with either a dominant or a subordinate. French preschoolers identified with the dominant, but Japanese preschoolers were at chance. Experiment 2 revealed that Japanese preschoolers were more likely to believe a subordinate than a dominant individual, both compared to chance and compared to previous findings among French preschoolers. The convergent results from both experiments thus reveal an early emerging cross-cultural difference in the valuing of dominance. (shrink)

In many circumstances we tend to assume that other people believe or desire what we ourselves believe or desire. This has been labeled 'egocentric bias.' This is not to say that we systematically fail to understand other people and forget that they can have a different perspective. If it were the case, then it would be highly difficult, if not impossible, to communicate, cooperate or compete with them. In those situations, we need to take the other person's perspective and to (...) inhibit our own. But can the other's perspective furtively intrude even when no reason seems to require it, or even when it is detrimental for us? We shall see a series of evidence of what has been called altercentric bias (Samson et al., 2010; Apperly, 2011): other people's beliefs can unduly influence us even when they are wrong. At first sight, altercentric bias questions 1st person priority. In particular, it may appear as incompatible with simulation-based accounts of 3rd person mindreading. We shall argue, on the contrary, that the simulationist framework enables confusions between self and others that go both ways: taking one's beliefs for the other's beliefs (egocentric bias) and vice-versa, taking the other's beliefs for one's beliefs (altercentric bias). We shall then see how the risk of such confusion may be disadvantageous from an evolutionary perspective, questioning thus the evolutionary plausibility of the simulation theory. (shrink)

As the title “Doing without Concepts” suggests Edouard Machery argues that psychologists should stop using the notion of concept because: (1) the only interesting generalizations about concepts can be drawn at the level of types of concepts (prototypes, exemplars and theories) and not the level of concept in general; and (2) competences such as categorization or induction can rely on these different types of concepts (there is not a one to one correspondence between type of concept and competence). I try (...) to make the point that these two elements are not wholly compatible. If several types of concepts are used to perform a given competence (point (2)), then they have to be well regulated (e.g. which type is activated when, which type wins in case of conflict). These regulatory mechanisms can then be the basis for interesting generalizations (against point (1)). On the other hand, it is possible that point (1) applies to competences as well: that there are no interesting generalizations to be drawn about categorization in general. In which case different types of categorization are likely to be underlain by different types of concepts (against point (2)). Even though the arguments laid out in the book are forceful and well supported by empirical evidence, a more positive thesis might have been both more successful rhetorically and more interesting scientifically. (shrink)

In studying how lay people evaluate arguments, psychologists have typically focused on logical form and content. This emphasis has masked an important yet underappreciated aspect of everyday argument evaluation: social cues to argument strength. Here we focus on the ways in which observers evaluate arguments by the reaction they evoke in an audience. This type of evaluation is likely to occur either when people are not privy to the content of the arguments or when they are not expert enough to (...) appropriately evaluate it. Four experiments explore cues that participants might take into account in evaluating arguments from the reaction of the audience. They demonstrate that participants can use audience motivation, expertise, and size as clues to argument quality. By contrast we find no evidence that participants take audience diversity into account. (shrink)

The Condorcet Jury Theorem, along with empirical results, establishes the accuracy of majority voting in a broad range of conditions. Here we investigate whether naïve participants (in the U.S. and...

In a great variety of cultures oaths, ordeals, or lie detectors are used to adjudicate in trials, even though they do not reliably discern liars from truth tellers. I suggest that these practices owe their cultural success to the triggering of cognitive mechanisms that make them more culturally attractive. Informal oaths would trigger mechanisms related to commitment in communication. Oaths used in judicial contexts, by invoking supernatural punishments, would trigger intuitions of immanent justice, linking misfortunes following an oath with perjury. (...) These intuitions would justify the infliction of costs on oath takers in a way that appears morally justified. Ordeals reflect the same logic. Intuitions about immanent justice link a worse outcome following the ordeal with a guilty verdict. This link justifies the application of the ordeal, and the fixed costs involved. Lie detectors also rely on the creation of a link between a specified outcome and a guilty verdict. However, they do not rely on intuitions about immanent justice, but on a variety of intuitions ranging from the plausibly universal to the culturally idiosyncratic. As a result, lie detectors involve lower fixed costs than ordeals, and are less cross-culturally successful than oaths or ordeals. (shrink)

Many experiments suggest that participants are more critical of arguments that challenge their views or that come from untrustworthy sources. However, other results suggest that this might not be true of demonstrative arguments. A series of four experiments tested whether people are influenced by two factors when they evaluate demonstrative arguments: how confident they are in the answer being challenged by the argument, and how much they trust the source of the argument. Participants were not affected by their confidence in (...) the answer challenged by the argument. By contrast, they were sometimes affected by their trust in the argument’s source. Analyses of reaction times and transfer problems suggest that source trustworthiness did not directly affect argument evaluation, but affected instead the number of times the participants considered the arguments. Our results thus suggest that people can evaluate demonstrative arguments objectively. In conclusion, we defend the hypothesis that people might also be able to evaluate non-demonstrative arguments objectively. These results support the predictions of the argumentative theory of reasoning. (shrink)

The Pigeonhole Principle states that if n items are sorted into m categories and if n > m, then at least one category must contain more than one item. For instance, if 22 pigeons are put into 17 pigeonholes, at least one pigeonhole must contain more than one pigeon. This principle seems intuitive, yet when told about a city with 220,000 inhabitants none of whom has more than 170,000 hairs on their head, many people think that it is merely likely (...) that two inhabitants have the exact same number of hair. This failure to apply the Pigeonhole Principle might be due to the large numbers used, or to the cardinal rather than nominal presentation of these numbers. We show that performance improved both when the numbers are presented nominally, and when they are small, albeit less so. We discuss potential interpretations of these results in terms of intuition and reasoning. (shrink)

Although there might seem to be a natural continuity and interplay between the cognitive sciences and the social sciences, the integration of the two has, on the whole, been fraught with difficulties. In some areas the transition was relatively smooth. For instance, political psychology is now a well-recognized branch both of psychology and of political science. In economics, things have been more difficult, with the entrenched assumption of a perfectly rational homo economicus, but behavioral economics is now well recognized, and (...) one of the founders of the field, Daniel Kahneman, went on to win a Nobel Prize.Social and cognitive sciences have proven more difficult to bridge in anthropology and sociology. Most of the efforts have been pursued—and resisted—in anthropology (although, for sociology, see Clément and Kaufmann 2011). At first, scholars attempted to import the methods of evolutionary biology straight into the study of culture (Dawkins 1976; Lumsden and Wilson 1981). This prom .. (shrink)

We agree with Cushman that rationalizations are the product of biological adaptations, but we disagree about their function. The data available do not show that rationalizations allow us to reason better and make better decisions. The data suggest instead that rationalizations serve reputation management goals, and that they affect our behaviors because we are held accountable by our peers.

In many judicial systems, confessions are a requirement for criminal conviction. Even if confessions are intrinsically convincing, this might not entirely explain why they play such a paramount role. In addition, it has been suggested that confessions owe their importance to their legitimizing role, explaining why they could be required even when other evidence has convinced a judge. But why would confessions be particularly suited to justify verdicts? One possibility is that they can be more easily transmitted from one individual (...) to the next, and thus spread in the population without losing their convincingness. 360 English-speaking participants were asked to evaluate the convincingness of one of three justifications for a verdict, grounded either in a confession, eyewitnesses, or circumstantial evidence, and to pass on that justification to another participant, who performed the same task. Then, 240 English-speaking participants evaluated the convincingness of some of the justifications produced by the first group of participants. Compared to the other justifications, justifications based on confessions lost less of their convincingness in the transmission process. Modeling pointed to the most common forms the justifications would take as they are transmitted, and results showed that the most common variant of the justification based on a confession was more convincing. (shrink)