Illuminating Mental Representations Through Speech and Gesture

Can the gestures people produce when describing algebra word problems offer insight into their mental representations of the problems? Twenty adults were asked to describe six word problems about constant change, and then to talk aloud as they solved the problems. Two problems depicted continuous change, two depicted discrete change, and two depicted change that could be construed as either continuous or discrete. Participants' verbal and gestured descriptions of the problems often incorporated information about manner of change. However, the information conveyed in gesture was not always the same as the information conveyed in speech. Participants' problem representations, as expressed in speech and gesture, were systematically related to their problem solutions. When gesture reinforced the representation expressed in the spoken description, participants were very likely to solve the problem using a strategy compatible with that representation—much more likely than when gesture did not reinforce the spoken description. The results indicate that gesture and speech together provide a better index of mental representation than speech alone.