Hand use and gestural communication in chimpanzees (Pan troglodytes).

Hand use in gestural communication was examined in 115 captive chimpanzees (Pan troglodytes). Hand use was measured in subjects while they gestured to food placed out of their reach. The distribution of hand use was examined in relation to sex, age, rearing history, gesture type, and whether the subjects vocalized while gesturing. Overall, significantly more chimpanzees, especially females and adults, gestured with their right than with their left hand. Foods begs were more lateralized to the right hand than pointing, and a greater prevalence of right-hand gesturing was found in subjects who simultaneously vocalized than those who did not. Taken together, these data suggest that referential, intentional communicative behaviors, in the form of gestures, are lateralized to the left hemisphere in chimpanzees.