20. Memory-processes that develop from recognitions which have been often repeated and from cognitions, are in consequence of the greater complexity of their conditions, different from those connected with the recognition of objects perceived but once.
When we perceive an object that is familiar either in its own individual characteristics or in those of its class, the range of possible associations is incomparably greater, and the way in which the memory-processes shall arise from a particular impression depend less on the single experiences that give rise to the association, than it does on the general disposition and momentary mood of consciousness and especially on the interference of certain active apperceptive processes and the intellectual feelings and emotions that are connected with them. When the conditions are so various, it is easy to see that as a general thing it is impossible, to calculate beforehand what the association will be. As soon as the act of memory is ended, however, the traces of its associative origin seldom escape careful examination, so that we are justified in regarding association as the universal and, only cause of memory-processes under all circumstances.
21. In thus deriving memory from association, it is not to be forgotten that every concrete memory-process is by no means a simple process, but is made up of a large number of elementary processes, as is apparent from the fact that it produced by a psychological development of its simple antecedents, namely, the simultaneous assassinations. The most important of these elementary processes is the assimilative [p. 245] interaction between some external impression and the elements of an earlier psychical compound, or between a memory-image already present and such elements. Connected with this there are two other processes that are characteristic for memory processes: one is the hindrance of the assimilation by unlike elements, the other the assassinations and complications connected with these elements and giving rise to a psychical compound which differs from the first impression and is referred more or less definitely to some previous experience, especially through its complications. This reference to the earlier experience shows itself through a characteristic feeling, the feeling of remembering, which is related to the feeling of familiarity, but is in its temporal genesis characteristically different, probably in consequence of the greater number of obscure complications that accompany the appearance of the memory-image.
If we try to find the elementary processes to which both memory-processes and all complex associations are reducible, we shall find two kinds, combinations from identity and from contiguity. In general the first class is predominant when the process is more like an ordinary assimilation and recognition, while the second appears more prominently the more the processes approach mediate memory in character, that is, the more they take on the semblance of spontaneous ideas.