This dissertation examines speakers’ production of speech and representational gesture. It utilizes the Repetition Effect as the investigative tool. The Repetition Effect appears to vary by the tendency for some items to shorten when repeating, at least under the condition that speakers can primarily operate by their assumption of the state of knowledge of the listener.
In speech, a highly conventionalized form of performance, word duration reduces within the same stretch of coherent discourse; then, it resets in the first mention of a new stretch of coherent discourse regardless of the state of knowledge to the speaker or the listener. Therefore, the Repetition Effect in speech is best analyzed as an automatic behavior triggered by discourse structure, rather than reflecting online changes in word accessibility for either interlocutor, be it for the speaker (Listener-neutral explanation) or for the listener (Listener-modeling explanation). The Repetition Effect in speech production in this dissertation will be accounted for within an exemplar model of the perception/production loop.
However, in representational gestures, a much less conventionalized form of performance compared to speech, the Repetition Effect shows a different pattern. When speakers only operate by their assumption of the state of knowledge of the listener, without dynamic, appreciable listener feedback, they steadily reduce most types of representational gesture across tellings. Based on these results, it can be argued that representational gestures primarily serve as a part of speech production, rather than as communicative acts. That is, they are produced without regard to the novelty of the information to the listener, thus, consistent with the Listener-neutral explanation
