Abstract Personality and social development begins before birth in the communication among mother, child and environment, during sensitive periods when the child's brain and body are plastic and epigenetically co-constructed. Triune ethics theory postulates three evolved, neurobiologically-based ethics fostered by early life experience. The security ethic is selfprotective. The engagement ethic is relationally attuned. The imagination ethic can abstract from the present moment and imagine alternatives. Climates and cultures can foster one or another ethic. Ancestral environments were more conducive to moral development. Individuals can adopt self-authorship of their moral character through the development of ethical expertise. Recommendations are made for research and policies that study and support optimal moral development
