Drawn up at the conference of editors and business managers of anthropological and psychological periodicals held in Washington, D. C., November 30 and December 1, 1928, under the auspices of the National Research Council. (PsycINFO Database Record (c) 2006 APA, all rights reserved)

The Province of Psychology.-In recent psychological 1 This and the two preceding statements should of course be qualified so as to include the simple phenomena occurring in protozoa, which have no nervous system or 'neural activity* properly speaking.In these creatures an equivalent mode of activity is observed, though its structural basis is far less definitely organized.The term specific in the definition is intended to exclude the trophic phenomena of the nerve cells, with which psychology is not directly concerned.'The term adaptation, fitness of result, is not to be confused with adjustment, the linking up of sensory and motor impulses.

The relation of recent work in genetics to the Darwinian theory is still in dispute. The value of the natural selection hypothesis can only be determined by appropriate experimental tests. At present there appears to be no inherent incompatibility between DARWIN’S fundamental principles and the newer concepts of pure lines, mutations, and unit characters. To some the action of natural selection seems to furnish an explanation of the actual trend of organic evolution which is lacking in later theories. The “pure line” concept does not assist materially in explaining the existing diversity of species. If a pure line remain unchanged indefinitely it is difficult to account for the host of pure lines that exist at present. If, on the other hand, a real variation can occur in a pure line now and again, natural selection would help to explain the trend toward adaptive characters which these lines exhibit. The “mutation” concept may represent the actual nature of variation better than the Darwinian notion of small fluctuating changes. Yet this scarcely affects DARWIN’S main contentions. The magnitude and frequency of the variations are relatively unimportant, since in any case such variations will accumulate in the course of generations. Their adaptiveness, however, is highly significant for biology, and the question remains whether adaptive variations can sort themselves out from nonadaptive by the mere working of natural selection, without the action of a vital force or entelechy. Finally, the Mendelian concept of “unit characters” in no way precludes the action of natural selection. Indeed it would seem to render easier the submission of the natural selection hypothesis to a crucial experimental test. I t should be noted, however, that the method generally employed in genetic work is not “natural” but “artificial” selection. Experimental-