Sperber and Wilson outline their "relevance theory" perspective on metaphor in their chapter ("A Deflationary Account of Metaphors"). Under this view, speaking metaphorically is an example of "loose talk" that often is the best way to achieve optimal relevance. Even though verbal metaphors do not represent a completely accurate state of affairs, listeners are able to infer efficiently the appropriate contextual meanings of metaphors by creating ad hoc concepts following the principle of optimal relevance. Ad hoc concept construction is a process that is typical of metaphorical interpretations, but it is not exclusive to metaphors. In general, relevance theory maintains that metaphors are nothing special in terms of their processing, even if metaphors often convey special cognitive effects or meanings not easily communicated by more direct speech. (Raymond Gibbs)