“Early psychology was based on the study of the individual; early sociology was based on the study of society. But there is no such thing as the "individual," there is no such thing as "society"; there is only the group and the group-unit — the social individual. Social psychology must begin with an intensive study of the group, of the selective processes which go on within it, the differentiated reactions, the likenesses and unlikenesses, and the spiritual energy which unites them.”