Dan Sperber

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.

There is a conventional discourse in favor of interdisciplinary research. At the same time there is much indifference or even disregard for such research and there are important institutional obstacles to its development. This first contribution to a virtual seminar aims at feeding reflexion on the conditions in which this research is either truly beneficial, even necessary, or is of little value. Favorable conditions for interdisciplinary research have a history, linked to that of scientific disciplines and their institutions. Is this history in the process of taking a new turn with the development of new forms of scientific communication through the Internet? I draw on my experience in the social and the cognitive sciences to reflect on the strength and weaknesses of interdisciplinary research and on its future.

Although a few pioneers in psycholinguistics had, for more than twenty years, approached various pragmatic issues experimentally, it is only in the past few years that investigators have begun employing the experimental method in testing pragmatic hypotheses. We see this emergence of a proper experimental pragmatics as an important advance with a great potential for further development. In this chapter we want to illustrate what can be done with experimental approaches to pragmatic issues by presenting one case, that of so-called ‘scalar inferences’, where the experimental method has helped sharpen a theoretical debate and has provided uniquely relevant evidence. We will focus on work done by the first author and his collaborators or work closely related to theirs, but other authors have also made important contributions to the topic