Dan Sperber

Groups do better at reasoning tasks than individuals, and, in some cases, do even better than any of their individual members. Here is an illustration. In the standard version of Wason selection task (Wason, 1966), the most commonly studied problem in the psychology of reasoning, only about 10% of participants give the correct solution, even though it can be arrived at by elementary deductive reasoning.1 Such poor performance begs for an explanation, and a great many have been offered. What makes the selection task relevant here is that the difference between individual and group performance is striking. Moshman & Geil for instance (1998, see also Maciejovsky & Budescu, 2007) had participants try and resolve the task either individually or in groups of five or six participants. While, unsurprisingly, only 9% of the participants working on their own found the correct solution, an astonishing 70% of the groups did. Moreover, when groups were formed with participants who had first tried to solve the task individually, 80% of the groups succeeded, including 30% of the groups in which none of the members had succeeded on his or her own. How are such differences between individual and group performance to be explained?

Our main aim in this paper is to show that constructing an adequate theory of communication involves going beyond Grice’s notion of speaker’s meaning. After considering some of the difficulties raised by Grice’s three-clause definition of speaker’s meaning, we argue that the characterisation of ostensive communication introduced in relevance theory can provide a conceptually unified explanation of a much wider range of communicative acts than Grice was concerned with, including cases of both ‘showing that’ and ‘telling that’, and with both determinate and indeterminate import.

Our book Relevance (Sperber and Wilson 1986) treats utterance interpretation as a two-phase process: a modular decoding phase is seen as providing input to a central inferential phase in which a linguistically encoded logical form is contextually enriched and used to construct a hypothesis about the speaker's informative intention. Relevance was mainly concerned with the inferential phase of comprehension: we had to answer Fodor's challenge that while decoding processes are quite well understood, inferential processes are not only not understood, but perhaps not even understandable (see Fodor 1983). Here we will look more closely at the decoding phase and consider what types of information may be linguistically encoded, and how the borderline between decoding and inference can be drawn. It might be that all linguistically encoded information is cut to a single pattern: all truth conditions, say, or all instructions for use. However, there is a robust intuition that two basic types of meaning can be found. This intuition surfaces in a variety of distinctions: between describing and indicating, stating and showing, saying and conventionally implicating, or between truth-conditional and non-truth-conditional, conceptual and procedural, or representational and computational meaning. In the literature, justifications for these distinctions have been developed in both strictly linguistic and more broadly cognitive terms. The linguistic justification goes as follows (see for example Recanati 1987). Utterances express propositions; propositions have truth conditions; but the meaning of an utterance is not exhausted by its truth conditions, i.e. the truth conditions of the proposition expressed. An utterance not only expresses a proposition but is used to perform a variety of speech acts. It can..

The idea that cultural evolution exhibits variation, competition, and inheritance and therefore can be studied by adjusting the Darwinian theory of evolution by natural selection is an attractive one. It has been argued by a number of authors (e.g., Campbell 1960; Monod 1970; Dawkins 1976; Cavalli-Sforza and Feldman 1981; Boyd and Richerson 1985; Durham 1991; Aunger 2002; Mesoudi et al. 2004) and pursued in a variety of ways, some (Dawkins and memeticists) staying close to the Darwinian model, others (e.g., Boyd, Richerson, and their collaborators) being more innovative. We agree that there are relevant analogies between biological and cultural evolution and, in particular, that cultural items do exhibit variation, competition, and cumulative modification. On the other hand, we believe that a proper understanding of the mechanisms of cultural propagation drawing on the work of cognitive and social scientists (see Sperber and Hirschfeld 1999 for a review) contradicts the idea that culture exhibits inheritance in the strict sense needed for the theory of evolution by natural selection to apply straightforwardly to it. If so, it will take more than adjusting the Darwinian model to be faithful to the Darwinian inspiration.

Humans have two kinds of beliefs, intuitive beliefs and reflective beliefs. Intuitive beliefs are a fundamental category of cognition, defined in the architecture of the mind. They are formulated in an intuitive mental lexicon. Humans are also capable of entertaining an indefinite variety of higher‐order or‘reflective’propositional attitudes, many of which are of a credat sort. Reasons to hold reflective beliefs are provided by other beliefs that describe the source of the reflective belief as reliable, or that provide an explicit argument in favour of the reflective belief. The mental lexicon of reflective beliefs includes not only intuitive, but also reflective concepts.