“The unifying theme is unmistakable: the group to which an individual belongs is the ground for his perceptions, his feelings, and his actions. Most psychologists are so preoccupied with the salient features of the individual’s mental life that they are prone to forget it is the ground of the social group that gives to the individual his figured character.
Just as the bed of a stream shapes the direction and tempo of the flow of water, so does the group determine the current of an individual’s life. This interdependence of the ground and the figured flow is inescapable, intimate, dynamic, but it is also elusive.”
— Kurt Lewin, Resolving Social Conflicts: Selected Papers on Group Dynamics (1948)