Morality and religion have evolutionary and cultural roots in the social behavior of our ancestors . Fundamental precursors and major features of morality and religion appear to have changed gradually in concert with social transitions in our history. These correlated changes involve trends toward increased breadth and complexity of social interaction, leading to a stepwise extension of the scope of human sympathies to more inclusive social categories, and eventually the universalization of moral and religious concepts, practices, and explanations. These changes can be integrated provisionally into an eight-stage model of human social history, beginning with nepotism and dominance that are characteristic of many social mammals, and culminating in the intellectual ability and (sometimes) social freedom of modern human individuals to examine moral and religious conventions, to modify or reject them, and even to propose new ones.