AP'PERCEP'TION (Lat. ad, in addition to percipere, to seize entirely, observe, perceive). A term first employed by Leibnitz (1646-1716), for whom it signified a spontaneous activity of the ego which exercised such a modifying influ ence upon the crude "perceptions" of sense that they became transformed into clear and ordered elements of knowledge. This metaphysical con cept was used by Kant (1724-1804) in his epistemology, with sharp emphasis upon the spontaneity of the activity. On the other hand, the term was taken over into psychology by Iler hart (1776-1841) and his followers, has been reformed and exhaustively treated by Wundt, and more recently has received extended discus sion at the hands of the English psychologist Stout.
Eerbart and his school, especially Lazarus (1824) and Steinthal (1823-99), lay stress upon the practical significance of apperception. This principle forms, indeed, the corner-stone both of their psychology and of all modern theories of education based upon it. Apperception is "that psychical activity by which individual perceptions, ideas, or ideational complexes are brought into relation to our previous intel lectual and emotional life, associated with it, and thus raised to greater clearness, activity, and significance." The mental resultant of previous experience wherewith we meet and re ceive a new experience is termed an "appercep tion mass." There will, of course, be individual variations in the nature of this mass; different minds are unequally prepared for a particular experience. One child will call butterflies "fly ing pansies"; another knows them to be in sects. Thus, from the Ilerbartian standpoint, it is of extreme importance for the teacher to acquaint himself with the existing store of ideas in the minds of the children under his charge. in order that the new matter which he presents may be received by appropriate thought-atti tudes.
Wundt's treatment combines the psychological acumen of Herbart with the Kantian emphasis upon spontaneity as the characteristic feature of apperception. It includes a. careful analysis of the experience of spontaneity into its ulti mate psychical and physiological conditions. The salient points of Wundt's doctrine are as fol lows: Apperception designates (1) either cer tain phenomena actually given in consciousness, or (2) a certain activity which we infer from these conscious data—i.e., a concept or category
under which the phenomena are grouped. As regards the phenomena themselves, we have to note first that the different components of a given consciousness vary in prominence. Some ideas are clear, standing in the focus of atten tion (q.v.) : others are obscure. Ideas may. then, be in consciousness and yet not be "apper ceived." Furthermore, the relation is not fixed. An idea may disappear from the focus of atten tion and another, previously obscure, take its place. Clearness is not, like quality or extent of sensation, dependent merely upon the character of the stimulus. It is not, like intensity, which it most resembles, a function of a single idea, but attaches to a number of ideas. Now the entrance of an idea into the focus of attention is by no means a simple matter. Analysis dis closes, besides the increase of the given idea in clearness, (1) a feeling of activity, (2) inhibi tion of other ideas, (3) strain sensations and concomitant feelings which intensify the feeling of activity, and (4) the reflex effect of (3), which intensifies the given idea. A careful examination of Wundt's writings show's that the "feeling of activity" is not ultimate and un analyzable, distinct from either sensation or affection (q.v.), but rather a conventional term representing a complex of sensation and affec tion from the presence of which in consciousness we infer an activity or spontaneity. Wundt distinguishes between "active" a pperception, marked by the feeling of activity, and "passive" apperception, marked by a feeling of passivity, a lessening of the intensity of the concomitant phenomena, and less clearness of the focal idea. In typical passive apperception the clarifying of the idea is determined unequivocally and im mediately. In active apperception there are several rival ideas; the result is equivocal and frequently delayed. The conditions of apper ception are either (1) objective, viz., (a) the intensity, and (b) the frequency of the presented occurrence; or (2) subjective, viz., (a) the na ture of the immediately preceding consciousness, and (b) the individual disposition of the mind, as determined by its entire previous history.