Cooperative behaviors such as helping, sharing, and collaboration are important components of human social life. Here, we summarize recent experiments that provide insight into both the ontogenetic and phylogenetic origins of these behaviors. Specifically, by combining a developmental and comparative approach, these experiments investigate the emergence of these behaviors in human ontogeny, and highlight similarities as well as differences with those of chimpanzees and bonobos. We review altruistic and mutualistic behaviors as two broad classes of cooperative behaviors that are underlain by different motivational and cognitive processes, emphasizing the importance of investigating proximate mechanisms to gain a comprehensive understanding of human cooperation.