Why Do We Gesture When We Speak?

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: quot;As the tongue speaketh to the ear, so the gesture speaketh to the eye quot; (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. How might gesturing affect lexical retrieval? Human memory employs several different formats to represent knowledge, and much of the content of