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 we re asked to describe six word problems about constant change, and then to t alk aloud as they solved the problems. Two problems depicted continuous cha nge, two depicted discrete change, and two depicted change that could be co nstrued as either continuous or discrete. Participants' verbal and gestured descriptions of the problems often incorporated information about manner o f change. However the information conveyed in gesture was not always the sa me as the information conveyed in speech. Participants' problem representat ions, as expressed in speech and gesture, were systematically related to th eir problem solutions. When gesture reinforced the representation expressed in the spoken description, participants were very likely to solve the prob lem using a strategy compatible with that representation-much more likely t han when gesture did not reinforce the spoken description. The results indi cate that gesture and speech together provide a better index of mental repr esentation than speech alone.