ABSTRACT
From the beginning of stage 3 of sensorimotor development fundamental differences have been found to characterize the development of nonhuman primate sensorimotor intelligence in comparison to that of the human infant. There are two indexes that reveal and attest the beginning of fully spatialized and objective causality. The behavior pattern of the supports is the first interesting case: drawing some bulky object toward oneself to reach objects placed upon it. In the support problem, therefore, the relation of spatial contact between the target and the intermediary object is established by the experimenter: what we want to see is whether the subject recognizes it as a necessary condition for the existence of a causal effect of the intermediary on the target object. In the few instances in which this problem has been offered to nonhuman primates positive results have been reported.
