Fig. S2.

Three young chimpanzees, A, B, and C, were exposed to two initially alarming objects, a swing and a satellite (moving ball). Every 2 mo, one of the three chimpanzees was replaced by a naive one, as indicated in the sequence BCD, CDE, and so on. Adaptive bolder approaches were socially inherited and over time came to dominate, resulting in a culture of common contact with the objects (86).