Dan Sperber

Short abstract (98 words). 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 humans’ exceptional dependence on communication and 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.

Social learning mechanisms are usually assumed to explain both the spread and the persistence of cultural behaviour. In a recent article, we showed that the fidelity of social learning commonly found in transmission chain experiments is not high enough to explain cultural stability. Here we want to both enrich and qualify this conclusion by looking at the case of song transmission in song birds, which can be faithful to the point of being true replication. We argue that this high fidelity results from natural selection pressure on cognitive mechanisms. This observation strengthens our main argument. Social learning mechanisms are unlikely to be faithful enough to explain cultural stability because they are generally selected not for high fidelity but for generalisation and adjustment to the individual’s needs, capacities and situation

In two experiments, we investigated whether 13-month-old infants expect agents to behave in a way consistent with information to which they have been exposed. Infants watched animations in which an animal was either provided information or prevented from gathering information about the actual location of an object. The animal then searched successfully or failed to retrieve it. Infants’ looking times suggest that they expected searches to be effective when—and only when—the agent had had access to the relevant information. This result supports the view that infants’ possess an incipient metarepresentational ability that permits them to attribute beliefs to agents. We discuss the viability of more conservative explanations and the relationship between this early ability and later forms of ‘theory of mind’ that appear only after children have become experienced verbal communicators.

Experimental evidence on reasoning and decision making has been used to argue both that human rationality is adequate and that it is defective. The idea that reasoning involves not one but two mental systems (see Evans and Over, 1996; Sloman, 1996; Stanovich, 2004 for reasoning, and Kahneman and Frederick, 2005 for decision making) makes better sense of this evidence. ‘System 1’ reasoning is fast, automatic, and mostly unconscious; it relies on ‘fast and frugal’ heuristics (to use Gigerenzer’s expression (Gigerenzer et al., 1999)) offering seemingly effortless conclusions that are generally appropriate in most settings, but may be faulty, for instance in experimental situations devised to test the limits of human reasoning abilities. ‘System 2’ reasoning is slow, consciously controlled and effortful, but makes it possible to follow normative rules and to overcome the shortcomings of system 1 (Evans and Over, 1996). The occurrence of both sound and unsound inferences in reasoning experiments and more generally in everyday human thinking can be explained by the roles played by these two kinds of processes. Depending on the problem, the context, and the person (the ability for system 2 reasoning is usually seen as varying widely between individuals, see Stanovich and West (2000)) either system 1 or system 2 reasoning is more likely to be activated, with different consequences for people’s ability to reach the normatively correct solution (Evans, 2006). The two systems can even compete: system 1 suggests an intuitively appealing response while system 2 tries to inhibit this response and to impose its own norm-guided one. Much evidence has accumulated in favour of such a dual view of reasoning (Evans, 2003, in press; for arguments against, see Osman, 2004). 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— which, depending on the specific dual process theory, are attributed more or less exclusively to one of the two systems..

How are non-declarative sentences understood? How do they differ semantically from their declarative counterparts? Answers to these questions once made direct appeal to the notion of illocutionary force. When they proved unsatisfactory, the fault was diagnosed as a failure to distinguish properly between mood and force. For some years now, efforts have been under way to develop a satisfactory account of the semantics of mood. In this paper, we consider the current achievements and future prospects of the mood-based semantic programme.

Members of a human group are bound with one another by multiple flows of information. (Here we use “information” in a broad sense that includes not only the content of people’s knowledge, but also that of their beliefs, assumptions, fictions, rules, norms, skills, maps, images, and so on.) This information is materially realized in the mental representations of the people, and in their public productions, that is, their cognitively guided behaviors and the enduring material traces of these behaviors. Mentally represented information is transmitted from individuals to individuals through public productions. Public representations such as speech, gestures, writing, or pictures are a special type of public productions, the function of which is to communicate a content. Public representations play a major role in information transmission. Much information, however, is communicated implicitly, that is, without being publicly represented. Information can also be transmitted without being properly speaking communicated, not even implicitly, as when one individual acquires a skill by observing and imitating the behavior of others. Most information transmitted among humans is about local and transient circumstances, and is not transmitted beyond these. Some information of more general relevance, however, is repeatedly transmitted, and propagates throughout the group. Talk of “culture” (whatever the preferred definition or theory of culture) is about this widely distributed information and about its material realizations inside people’s mind and in their common environment (see Sperber 1996). One can study cultural phenomena in two main ways. One can interpret them, that is, try and make their contents intelligible to people of another culture, or more intelligible to members of the culture in which these phenomena occurs, as do anthropologists and historians. One may also try and explain causally how these cultural phenomena emerge, stabilize and evolve..

In Relevance: Communication and Cognition, we outline a new approach to the study of human communication, one based on a general view of human cognition. Attention and thought processes, we argue, automatically turn toward information that seems relevant: that is, capable of yielding cognitive effects – the more, and the more economically, the greater the relevance. We analyse both the nature ofcognitive effects and the inferential processes by which they are derived. Communication can be achieved by two different means: by encoding and decoding messages or by providing evidence for an intended inference about the communicator's informative intention. Verbal communication, we argue, exploits both types of process. The linguistic meaning of an utterance, recovered by specialised decoding processes, serves as the input to unspecialised central inferential processes by which the speaker's intentions are recognised. Fundamental to our account of inferential communication is the fact that to communicate is to claimsomeone's attention, and hence to imply that the information communicated is relevant. We call this idea, that communicated information comes with a guarantee of relevance, the principle of relevance. We show that every utterance has at most a single interpretation consistent with the principle of relevance, which is thus enough on its own to account for the interaction of linguistic meaning with contextual factors in disambiguation, reference assignment, the recovery of implicatures, the interpretation ofmetaphor and irony, the recovery of illocutionary force, and other linguistically underdetermined aspects of utterance interpretation.