1 6 Presidential Address.
motive for our interest has itself been determined in the main by mental factors. Its course has been dependent, partly on the nature of the psychological motives which have come into action during Man's struggle with his environ- ment, both material and social, and partly on the psycho- logical processes by which mental trends once adapted to crude and simple modes of life have been modified and developed to enable both the individual and the group to cope with the increasing complexity of human society.^
As I have pointed out elsewhere ^ the relation between psychology and the study of human culture is highly complex. On the one hand the historian, the ethnologist and the folk-lorist look to the psychologist for knowledge of the motives and processes which have prompted and guided human progress. On the other hand, social inter- actions and the products of these interactions provide material for the psychologist. The modern psychologist is not content to study by means of introspection the modes of activity of his own mind. He supplements these, or even wholly substitutes for them, the observation of behaviour of the animal, of the child, of his fellow-men, especially under peculiar conditions and pre-eminently when they are the victims of disease, and last, but far from least, of the collective behaviour which has found expression in the political institutions, the economic processes, the rehgious rites, and the material and aesthetic arts of the different forms of human society.
In the paper to which I have just referred I have suggested that at present the student of human cus- tom and belief can render a greater service to the psychologist than he can expect from him. The student of mind in the past, depending chiefly or wholly on introspection, has naturally had the individual as the
^ W. H. R. Rivers, Instinct and the Unconscious, 2nd ed., Cambridge, 1922.
2 " Sociology and Psychology," Sociological Review, 1916, vol. ix. p. i.
