Identification of the Social and Cognitive Processes Underlying Human Cumulative Culture

Acquire and Share Few would argue with the stance that human social cognition supports an unequaled capacity to acquire knowledge and to share it with others. Dean et al. (p. 1114; see the Perspective by Kurzban and Barrett) compared the extent to which these social and cognitive psychological processes can be elicited in children, capuchins, and chimpanzees through the use of a three-level puzzlebox task. Incentivized by improving rewards, 3- to 4-year-old children progressed from the first to the third level by imitating observed actions, taught other members of their social group how to solve the problem, and shared the rewards obtained. By contrast, neither the capuchins nor chimpanzees, very few of which ever reached the third level, exhibited these charactertistics. Humans not only watch and imitate each other but also learn from each other in multiple ways. The remarkable ecological and demographic success of humanity is largely attributed to our capacity for cumulative culture, with knowledge and technology accumulating over time, yet the social and cognitive capabilities that have enabled cumulative culture remain unclear. In a comparative study of sequential problem solving, we provided groups of capuchin monkeys, chimpanzees, and children with an experimental puzzlebox that could be solved in three stages to retrieve rewards of increasing desirability. The success of the children, but not of the chimpanzees or capuchins, in reaching higher-level solutions was strongly associated with a package of sociocognitive processes—including teaching through verbal instruction, imitation, and prosociality—that were observed only in the children and covaried with performance.