21 a. It is obvious that the usual classification, which makes all memory-processes associations by either similarity or contiguity, is entirely unsuitable if we attempt to apply it to the modes of psychological genesis that these processes manifest. On the other bland, it is too general and indefinite if we try to classify the processes logically according to their products, without reference to their genesis. In the latter case the various relations of subordination, superordination, and coordination, of cause and end, of temporal succession and existence, and the various kinds of spacial connection, find only inadequate expression in the very [p. 246] general concepts "similarity" and "contiguity". When, on the other hand, the manner of origin is studied, every memory-process is found to be made up of elementary processes that may be called partly associations by similarity, partly associations by contiguity. The assimilations which serve to introduce the process and also those which serve to bring about the reference to a particular earlier experience at its close, may be called associations by similarity. But the term "similarity" is not exactly suitable even here, because it is identical elementary processes that give rise to the assimilation, and when such an identity does not exist, it is always produced by the reciprocal assimilation. In fact, the concept of "association by similarity" is based on the presupposition that composite ideas are permanent psychical objects and that associations take place between these finished ideas. The concept itself must be rejected when once this presupposition is given up as entirely contradictory to psychical experience and fatal to a proper understanding of the same. When certain products of association, as, for example, two successive memory-images, are similar, this likeness is always reducible to processes of assimilation made up of elementary combinations through identity or contiguity. The association through identity may take place either between components that were originally the same, or between those that have gained this character through assimilation.

Association by contiguity is the form of combination between those elements that hinder the assimilation, thus dividing the whole process into a succession of two processes, and also contributing to the memory-image those components which give it the character of an independent compound different from that of the impression which gave rise to it.

22. The character of memory-ideas is intimately connected with the complex nature of the memory-processes. The description of these ideas as weaker, but otherwise faithful, copies of the direct sensible idea, is as far out of the way as it could possibly be. Memory-images and direct sensible ideas differ not only in quality and intensity, but most emphatically in ir elementary composition. We may diminish the intensity of a sensible impression as much as [p. 247] we like, but so long as it is perceptible at all it is an essentially different compound from a memory-idea. The incompleteness of the memory-idea is much more characteristic than the small intensity of its sensational elements. For example, when I remember an acquaintance, the image I have of his face and figure are not mere obscure reproductions of what I have in consciousness when I look directly at him, but most of the features do not exist at all in the reproduced ideas. Connected with the few ideational elements that are really present and that can be but little increased in number even when the attention is intentionally concentrated upon the task, are a series of combinations through contiguity and of complications, such as the environments in which I saw my acquaintance, his name, finally and more especially, certain affective elements that were present at the meeting.

These accompanying components are what make the image a memory-image.

23. There are great individual differences in the effectiveness of these accompanying elements and in the distinctness of the sensational elements of the memory-image. Some persons locate their memory-images in space and time much more precisely than others do; the ability to remember colors and tones is also exceedingly different. Very few persons seem to have distinct memories for odors and tastes; in place of these we have, as substitute complications, accompanying motor sensations of the nose and taste-organs.

These various different functions connected with the processes of recognition and remembering are all included under the name "memory". This concept does not, of course, refer to any unitary psychical force, as faculty-psychology assumed (p. 11), still, it is a useful supplementary concept in emphasizing the differences between different individuals. We speak of a faithful, comprehensive, and easy memory, or of a good [p. 247] spacial, temporal, and verbal memory, etc. These expressions serve to point out the different directions in which, according to the original disposition or habit of the person, the elementary assimilations and complications occur.

One important phenomenon among the various differences referred to, is the gradual weakening of memory with old age. The disturbances resulting from diseases of the brain agree in general with this phenomenon. Both are of special importance to psychology because they exhibit very clearly the influence of complications on memory-processes.

One of the most striking symptoms of failing memory, in both normal and pathological cases, is the weakening of verbal memory. It generally appears as a lack of ability to remember, first. proper names, then names of concrete objects in the ordinary environments, still later abstract words, and finally particles that are entirely abstract in character. This succession corresponds exactly to the possibility of substituting in consciousness for single classes of words other ideas that are regularly connected with them through complication. This possibility it obviously greatest for proper names, and least for abstract particles, which can be retained only through their verbal signs.

[ 1] The author [Wundt] remarks that the English word idea as here used corresponds to the German Vorstellung . Tr. [Judd]