This paper summarizes a series of naturalistic and experimental investigations into the nature of personal commitment and prosocial behavior. An intensive naturalistic study of Civil Rights workers distinguished those who were fully committed from those who were partially committed on the basis of parental models. The parent of the fully committed was a behavioral altruist, fully committed to a social cause, who maintained a strong positive relationship with the child. The parent of the partially committed often failed to practice what he or she preached, and maintained a negative or ambivalent relationship with the child. These observations were examined in experiments predicated on social learning theory. In one, adolescents who observed a model rebel against authority for prosocial reasons tended themselves subsequently to rebel more than their peers who had observed an obedient model. In another, children who observed a model contribute to charity tended also to contribute, even in the absence of adult surveillance. However, these findings, while statistically significant, were nevertheless quite weak. Additional experiments provided strong evidence that while observation of a model was helpful, internalization of prosocial norms was more strongly facilitated by the opportunity to rehearse prosocial behavior voluntarily with the model. In a series of developmental studies it was found that internalization of prosocial norms occurred rarely with five-year-old children, but quite commonly with eight- and nine-year-old ones. This finding was puzzling since the required behaviors were neither physically nor psychologically taxing. It was proposed that the internalization of prosocial behavior on the basis of observation of others may require a predisposing cognitive and affective matrix, the elements of which are briefly elaborated.