Goodwin, M. H. & Goodwin, C. (1986). Gesture and coparticipation in the activity of searching for a word. Semiotica, 62, 51-75.
Goodwin and Goodwin argue that word searches are not a speaker-only task. Instead, speakers indicate that word searches are active, and make bids to listeners to help resolve the lexical access difficulty–through extended pauses, filled pauses, a “thinking face” facial expression, and movements of the hands. They provide some detailed analyses of a few utterances to illustrate this concert of non-verbal signalling.