The argument that younger children have less mature cognitive capacities, so that benefits of concentrating on a cognitively demanding task decrease after a shorter time than for older children. Benefits, however, can be increased through taking breaks for play. A key feature of the hypothesis is that the cognitive abilities of children are not inferior variants of adult behavior, but rather specific adaptations to the niche of childhood that enables young children to learn new abilities in an effective way. Consequently, play is accorded an important role in the hypothesis.
See Cognition, Cognitive development, Cognitive psychology, Play