Investigation of the factors in natural history which conditioned the appearance of consciousness, that specifically human form of mental activity, necessarily presumes, in particular, a study of its functional preconditions or, in other words, of the higher forms of animal activity involving objects and of the corresponding mental processes. It is not enough to know the general psychological qualities of animals, the general principles by which their behavior is shaped, principles and properties offering evidence of a type of vital activity (...) qualitatively different from that of man. The traits of psychology and behavior, characteristic of the preponderance of the animal world, could not have become the immediate functional foundation capable of providing the real opportunity for the onset of the shaping of new regularities of mental activity. (shrink)