DO CHIMPANZEES COOPERATE IN A LEARNING-TASK

The aim of this study was to assess the ability of chimpanzees (Pan tr oglodytes) to cooperate in an instrumental task. A specially construct ed fruit distributor was presented to a group of six captive chimpanze es. A cooperative response required two chimpanzees: both had to pull a handle simultaneously to make a fruit fall into the cage. The domina nt male of the group and an infant produced most of the operant respon ses, and the male got nearly all the fruits. Other conspecifics avoide d the dominant male at the apparatus. Social influences appear to limi t the possibility of co-operation between individuals because a certai n level of interindividual tolerance is required. The results revealed a significant increase in the number of pulls each time both chimpanz ees were together at the apparatus. Operant chimpanzees learn to coord inate their actions in time and space.