ABSTRACT
The macaque has the most accelerated development in both absolute and relative terms: not only its development is the shortest of all species, but its first and second stages are also relatively shorter than in the other species. A variable of the utmost importance in determining the eventual course of development is the temporal relationship among the relative times of onset of various capacities, and this relationship will be different in the various species because of their varying rates of development at each stage. In stage 1 capacities are least differentiated and consequently there is the highest degree of uniformity among species. Stage 2 is marked by the establishment of reciprocal coordinations between primary schemata. In stage 3 of sensorimotor development differences among the four species increase. Stage 4 confirms and amplifies the pattern of differential development seen in the preceding stage. Cognitive constructions develop through the subject’s assimilative-accommodatory interaction with the environment.
