A technical term in philosophy, psychology, and sociology referring to the theory that mind and body, or individuals and society, interact and influence each other.
Interactionism is the idea that mind and body influence each other.
Compound of 相互 (sōgo, 'mutual') + 作用 (sayō, 'action') + 説 (setsu, 'theory'). A calque from English 'interactionism'.