Viewing the question from a different angle, we find another argument for the homogeneous character of the human mind in the fact that the patterns of interest of the civilized show no variation from those of the savage. Not only the appetites and vanities remain essentially the same, but, on the side of intellectual interest, the type of mental reaction fixed in the savage by the food-quest has come down unaltered to the man of science as well as to the man of the street. In circumventing enemies and capturing game, both the attention and the organic processes worked together in primitive man under great stress and strain. Whenever, indeed, a strain is thrown on the attention, the heart and organs of respiration are put under pressure also in their effort to assist the attention in manipulating the problem; and these organic fluctuations are felt as pleasure and pain. The strains thrown on the attention of primitive man were connected with his struggle for life; and not only in the actual encounter with men and animals did emotion run high, but the memory and anticipation of conflict reinstated the emotional conditions in those periods when he was meditating future conflicts and preparing his bows and arrows, traps and poisons. The problem of invention, the reflective and scientific side of his life, was suffused with interest, because the manufacture of the weapon was, psychologically speaking, a part of the fight. This type of interest, originating in the hunt, remains dominant in the mind down to the present time. Once constructed to take an interest in the hunting problem, it takes an interest in any problem whatever. Not only do hunting and fighting and all competitive games--which are of precisely the same psychological pattern as the hunt and fight--remain of perennial interest, but all the useful occupations are interesting in just the degree that this pattern is preserved. The man of science works at problems and uses his ingenuity in making an engine in the laboratory in the same way that primitive man used his mind in making a trap. So long as the problem is present, the interest is sustained; and the interest ceases when the problematical is removed. Consequently, all modern occupations of the hunting pattern--scientific investigation, law, medicine, the organization of business, trade speculation, and the arts and crafts--are interesting as a game; while those occupations into which the division of labor enters to the degree that the workman is not attempting to control a problem, and in which the same acts are repeated an indefinite number of times, lose interest and become extremely irksome.