The communication accommodation theory (CAT), developed by Howard Giles, professor of communication at the University of California, Santa Barbara, seeks to explain the cognitive reasons for code-switching, and other changes in speech, as a person either emphasizes or minimizes the social differences between himself and the other person(s) in conversation. Giles posits that when speakers seek approval in a social situation they are likely to converge their speech with that of the other speaker. This can include, but is not limited to, the language of choice, accent, dialect, and para-linguistic features used in the conversation. In contrast to convergence, speakers might also engage in divergent speech, in which an individual person emphasizes the social distance between himself and other speakers by using speech with linguistic features characteristic of his own group.