OBJECT CONCEPT AND MENTAL REPRESENTATION IN CEBUS-APELLA AND MACACA-FASCICULARIS

The achievement of Stage 6 object concept as an index of the representational capacity, was studied both in juveniles and adults of two nonhuman primate species, Cebus apella and Macaca fascicularis. The general goal of the present investigation was to evaluate the real nature of the strategy adopted by subjects searching an object in the invisible displacement task. To this purpose, the original Piagetian version of the invisible displacement task was used modifying some parameters and employing additional tasks and analyses in order to differentiate representational solutions from the nonrepresentational ones. With this method it was found that an adult cebus, but not macaques, solved the invisible displacement task with the use of the mental representation. © 1990 Japan Monkey Center.