Copyright © 1999 Massachusetts Institute of Technology
The notion of relevance has been used in many areas of cognitive science, including LOGIC, artificial intelligence and psychology of reasoning. This article focuses on the role of relevance in human communication, and presents a relevance-based theory of communication (Sperber and Wilson 1986/95) that has potential applications in broader domains.
The intuition that human communication is relevance-oriented is widely shared. Strawson (1964/1971: 92) put forward as a "general platitude" that he called the Principle of Relevance the claim that "stating is not a gratuitous and random human activity. We do not, except in social desperation, direct isolated and unconnected pieces of information at each other." However, recent approaches to PRAGMATICS have been sharply divided about how that intuition is to be explained. All current pragmatic treatments are influenced by the work of Paul GRICE (1967/1989), whose inferential approach to communication is fundamental.
Inferential communication succeeds when the communicator provides evidence of her intention to convey a certain thought, and the audience infers this intention from the evidence provided. Grice saw inferential intention-recognition as governed by a cooperative principle and maxims of quality, quantity, relation, and manner (truthfulness, informativeness, relevance, and clarity). He left the maxim of relation ("Be relevant") relatively undeveloped, and he acknowledged that its formulation concealed a number of problems that he found "exceedingly difficult" (Grice 1989: 46). Gazdar's comment (1979: 45), "That relevance is relevant to linguistic description is painfully apparent . . . . Equally apparent is the absence of any kind of formal treatment of the notion," reflects widespread skepticism about the possibility of progress in this area.
Theoretical accounts of relevance have taken two main forms. One links relevance to the notions of topic, interest, or concern. This approach was taken by Strawson (1964/1971: 92), whose Principle of Relevance was designed to capture the fact that we "intend in general to give or add information about what is a matter of standing or current interest or concern." Topic-based analyses have been proposed by Reinhart (1981) and Giora (1985), and criticized on the ground that the notion of topic is not only less clear but also less basic than the notion of relevance (Wilson 1998).
Another possibility is to link relevance to the notion of required information, following Grice's suggestion that a properly developed maxim of relevance might subsume his second Quantity maxim, "Do not make your contribution more informative than required." This approach is taken by Horn (1984), whose R-principle, "Make your contribution necessary; say no more than you must," is intended to subsume Grice's second Quantity maxim and his maxim of Relation. However, although the notions of information and degrees of informativeness are relatively easy to clarify, this approach sheds little light on what makes some information required, leaving the notion of relevance partially unexplained. (For discussion, see Carston 1998a.) Relevance theory (Sperber and Wilson 1986/1995) aims to remedy this defect by saying what makes information worth attending to, but without appealing to notions such as topic or interest.
Within relevance theory, relevance is treated as a property of inputs to cognitive processes and analyzed in terms of the notions of cognitive effect and processing effort. When an input (for example, an utterance) is processed in a context of available assumptions, it may yield some cognitive effect (for example, by modifying or reorganizing these assumptions). Other things being equal, the greater the cognitive effects, the greater the relevance of the input. However, the processing of the input, and the derivation of these effects, involves some mental effort. Other things being equal, the smaller the processing effort, the greater the relevance of the input.
On the basis of this definition, two general principles are proposed: the cognitive principle that human cognition tends to be geared to the maximization of relevance; and the communicative principle that every act of inferential communication communicates a presumption of its own optimal relevance (Sperber and Wilson 1986/1995, 1987). It follows from the cognitive principle of relevance that human attention and processing resources are allocated to information that seems relevant. It follows from the communicative principle of relevance (and the definition of optimal relevance; Sperber and Wilson 1986/1995: 266-278) that the speaker, by the very act of addressing someone, communicates that her utterance is the most relevant one compatible with her abilities and preferences, and is at least relevant enough to be worth the listener's processing effort.
Inferential comprehension starts with the recovery of a linguistically encoded logical form (see LOGICAL FORM IN LINGUISTICS; the goal of pragmatic theory is to explain how the hearer bridges the gap between the linguistically encoded logical form and the full intended interpretation of the utterance. The communicative principle of relevance motivates the following comprehension procedure, which, according to relevance theory, is automatically applied to the on-line processing of attended verbal inputs. The hearer takes the linguistically decoded logical form; following a path of least effort, he enriches it at the explicit level and complements it at the implicit level, until the resulting interpretation meets his expectations of relevance, at which point he stops. The mutual adjustment of explicit content and implicatures, constrained by expectations of relevance, is the central feature of relevance-theoretic pragmatics. (See Sperber and Wilson 1998.)
Relevance-theoretic pragmatics differs from other Gricean approaches in three main respects. It does not treat communication as necessarily cooperative in Grice's sense: for communication to be successful, the only goal that speaker and hearer need to share is that of understanding and being understood. It is not maxim-based: the communicative principle of relevance is not a maxim that speakers need to know, but a generalization about acts of inferential communication. It follows that deliberate maxim-violation, which is central to Gricean pragmatics, has no role in relevance- theoretic comprehension, and the examples that Griceans treat as involving maxim-violation must be reanalyzed.
The relevance-theoretic approach has potential applications in wider domains: for example, in the psychology of reasoning (Sperber, Cara, and Girotto 1995) and the analysis of autism (Happé 1993). For critique and discussion, see Behavioral and Brain Sciences (10.4: 1987).
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Copyright © 1999 Massachusetts Institute of Technology