A second cause for the control of instinct lies in the fact that people live and have to live together. The close association which is so characteristic of human life is, as we shall see, partly attributable to a specific gregarious instinct, partly to the increasing need for cooeperation which marks the increasing complexity of civilization. But whatever be its causes, group association makes it necessary that men regulate their impulses and actions with reference to one another. Endowed as human beings are with more or less identical sets of original native desires, the desires of one cannot be freely fulfilled without frequently coming into conflict with the similar desires of others. Compromise and adjustment must be brought about by some intelligent modification both of action and desire. The child's curiosity, the acquisitiveness or sex desire or self-assertiveness of the adult must be checked and modified in the interests of the group among which the individual lives. One may take a simple illustration from the everyday life of a large city. There is, for most individuals, an intrinsic satisfaction in fast and free movement. But that desire, exhibited in an automobile on a crowded thoroughfare, will interfere with just as normal, natural, and inevitable desires on the part of other motorists and pedestrians. Still another imperative reason for the control of our instinctive equipment lies in the fact that instincts as such are inadequate to adjust either the individual or the group to contemporary conditions. They were developed in the process of evolution as useful methods for enabling the human animal to cope with a radically different and incomparably simpler environment. While the problems and processes of his life and environment have grown more complex, man's inborn equipment for controlling the world he lives in has, through the long history of civilization, remained practically unchanged. But as his equipment of mechanisms for reacting to situations is the same as that of his prehistoric ancestors, so are his basic desires. And the satisfaction of man's primary impulses is less and less attainable through the simple, unmodified operation of the mechanisms of response with which they are associated. In the satisfaction of the desire for food, for example, which remains the same as it was under primitive forest conditions, much more complex trains of behavior are required than are provided by man's native equipment. To satisfy the hunger of the contemporary citizens of New York or London requires the transformation of capricious instinctive responses into systematic and controlled processes of habit and thought. The elaborate systems of agriculture, transportation, and exchange which are necessary in the satisfaction of the simplest wants of men in civilization could never be initiated or carried on if we depended on the instincts with which we are born.