Relevance
According to Sperber and Wilson, human cognition is driven by relevance in the sense that information (whether sensory-perceptual or linguistic) is selectively processed on the basis of the search for contextual effects: information that will affect our existing knowledge in some useful way or will allow us to con struct an inference. For example, imagine driving down the road in your car with the radio on. In this context, you are bombarded with sensory-perceptual stimuli including visual stimuli as well as linguistic and non-linguistic sounds. Suppose that you have been worried about your car lately. In this context, you might ‘tune out’ the linguistic sounds coming from the radio and focus your attention on the sounds coming from under the bonnet. Depending on whether these sounds are out of the ordinary or not, this information will interact with what you already know about your car and allow you to draw some conclusions. In this context, the car’s sounds are more relevant than the radio’s sounds. Now imagine that you are late for work and concerned about the time. You transfer your attention to the linguistic sounds coming from the radio and listen for the newsreader to announce the time. In this context, the radio’s sounds are more relevant than the car’s sounds. As this simple example illustrates, the human mind constantly searches for relevant information. This idea is captured by the ‘Cognitive Principle of Relevance’, which states that ‘Human cognition tends to be geared to the maximisation of relevance’ (Sperber and Wilson 1995: 158).
Sperber and Wilson argue that ostensive-inferential communication is driven by the presumption of relevance. In other words, a hearer will assume that any act of (linguistic or non-linguistic) ostensive-inferential communication is relevant, and moreover will search for the optimally relevant interpretation. It is this assumption that allows us to deduce or infer the communicative intention signalled by an act of ostensive communication. This idea is captured by the ‘Communicative Principle of Relevance’, which states that ‘Every act of ostensive communication communicates a presumption of its own optimal relevance’ (Sperber and Wilson 1995: 260). ‘Optimal relevance’ is defined in the following way:
Consider example (19) from Sperber and Wilson (1995: 189). Imagine that this utterance is made in a jeweller’s shop in response to an enquiry from a customer about how long they might expect to wait for the watch to be repaired.
It is obvious that a watch repair must take ‘some time’ (as opposed to no time), so the customer assumes that the communicative intention behind the utterance cannot be to convey this uninformative and therefore irrelevant interpretation. Sperber and Wilson argue that our presumption of relevance in everyday communication guides us to a more appropriate interpretation of the utterance. If the customer knows that it usually takes about a week to get a watch repaired, then the most relevant reason for mentioning the time it will take is probably because the repair will take significantly longer than a week.
