What we humans call ethics or morality depends on four interlocking brain processes: (1) caring (supported by the neuroendocrine system, and emerging in the young as a function of parental care). (2) Learning local social practices and the ways of others – by positive and negative reinforcement, by imitation, by trial and error, by various kinds of conditioning, and by analogy. (3) Recognition of others' psychological states (goals, feelings etc.). (4) Problem-solving in a social context. These four broad capacities are not unique to humans, but are probably uniquely developed in human brains by virtue of the expansion of the prefrontal cortex.