Any history of psychoeducation must include Kurt Lewin (1890-1947), a German-born psychologist and contemporary of Piaget and Erikson.  Frequently termed the "founder of social psychology," Lewin's work concerned the behavior of people in groups and organizations.  Initially schooled in behavioral psychology, he turned to gestalt psychology, which at the time concerned itself with human perception and the ways human beings organize their perceptual worlds. 

Lewin's studies led him to embrace an interactionist perspective on human behavior, one that eclipsed personality and environment.  He developed the equation B=ƒ(P,E)  to describe his belief that behavior is a function of both personality and environment.  Although this may seem obvious today, in Lewin's era the debate between those who believed nature was the driving force in behavior was heavily contested by those who thought nurture was the key element.  Lewin's perspective has spawned many models of human behavior which hark back to his original equation.

Lewin coined the term "life space," which (as you shall see) is quite meaningful to psychoeducation.  A person's "life space" consists of elements of outer (objective) reality and inner (subjective) reality, both of which interact and are to different degrees determinants of behavior.