Humans begin to behave prosocially at an early age; therefore, cooperation or prosociality is one of the most important foundations to succeed in human social relationships. How prevalent is prosocial behavior in non-human primates? How do they cooperate and help each other? The controversial topic of animal cognition has generated much argument about whether biological or social factors create the individual differences in prosocial behavior. Comparative studies have shown that non-human primates also engage in prosocial behaviors, but research have not provided consistent results due to primate differences in social structures, cognitive abilities, and sensitivities (Mustoe, Cavanaugh, Harnisch, Thompson, & French, 2015). Moreover, previous studies have shown that early maternal attachment for security plays a critical factor for social development, especially for complex social behaviors (Schlottmann & Seay, 1972). Therefore, it might be interesting to examine whether early material separation plays a significant role in reducing brown capuchins’ (Cebus apella) prosocial behavior.
