Commitment to this idea may well be reaction against the unbridled, atomistic individualism which has wreaked havoc in society as a whole and in innumerable lives, and which, as his books indicate, Steinbeck recognizes as disastrous for mankind. But he has swung to and remains at the opposite extreme, that amalgamism which deprives the individual of initiative, responsibility, value, and even metaphysical being, and makes him no more than a cell in a supposititious monstrosity called "group-man" or an inextricable aspect of a pseudo-mystical entity called the "great big soul."
Source: wiktionary