If, then, we make due allowance for our instinctive tendency as a white group to disparage outsiders, and, on the other hand, for our tendency to confuse progress in culture and general intelligence with biological modification of the brain, we shall have to reduce very much our usual estimate of the difference in mental capacity between ourselves and the lower races, if we do not eliminate it altogether; and we shall perhaps have to abandon altogether the view that there has been an increase in the mental capacity of the white race since prehistoric times.
The first question arising in this connection is whether any of the characteristic faculties of the human mind—perception, memory, inhibition, abstraction—are absent or noticeably weak in the lower races. If this is found to be true, we have reason to attribute the superiority of the white race to biological causes; otherwise we shall have to seek an explanation of white superiority in causes lying outside the brain.
In examining this question we need not dwell on the acuteness of the sense-perceptions, because these are not distinctively human. As a matter of fact, they are usually better developed in animals and in the lower races than in the civilized, because the lower mental life is more perceptive than ratiocinative. The memory of the lower races is also apparently quite as good as that of the higher. The memory of the Australian native or the Eskimo is quite as good as that of our “oldest inhabitant;” and probably no one would claim that the modern scientist has a better memory than the bard of the Homeric period.