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.