Students of human nature traditionally have considered conversational gestures—unplanned, articulate hand movements that accompany spontaneous speech— to be a medium for conveying semantic information, the visual counterpart of words.2 Over a century ago, Sir Francis Bacon put the relationship of gesture and language in the form of a simple analogy: "As the tongue spcakcth to the ear, so the gesture spcakcth to the eye" (Bacon, 1891).
Although the extent to which gestures serve a communicative function is presently a matter of some controversy,3 there is accumulating evidence that communication is not the only function such gestures serve. Over the past several years my colleagues and I have explored the hypothesis, casually suggested by a remarkably diverse group of writers over the past 60 years, that gestures help speakers formulate coherent speech by aiding in the retrieval of elusive words from lexical memory...