Principles of physiological psychology / translated from the Fifth edition by E.B. Tichener.

  • Wundt, Wilhelm Max, 1832-1920.
Date:
1904
Catalogue details

Licence: In copyright

Credit: Principles of physiological psychology / translated from the Fifth edition by E.B. Tichener. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    in the normal function ; and that the substitution consequently consists, again, simply in an enhancement of activities, along lines already familiar to the elements in their normal state. Looked at from this point of view, the appearance of aphasia after destruction of the speech centres of the left side would not imply that the speech functions had their exclusive seat in this left hemisphere, or, as has sometimes been suggested by those who support the hypothesis of word localisation, that only certain subordinate word forms, e.g. the interjections, are localised on the right. It is much more reasonable to suppose that the co-operation of neurone territories, where it is so extraordinarily complicated as it must be in a function of the complexity of speech, involves wide-spread areas in both halves of the brain ; though, as a matter of fact, the areas of the left hemisphere are normally the more practised, and their destruction accordingly produces specially obvious defects. The larger practice of the motor organs on the right as compared with those on the left hand side of the body furnishes an admirable parallel to this functional habituation. Genetically, it is, in all probability, related to the unequal development of the speech centres ; and factually, it repeats that inequality point by point. For the organs on the right hand side of the body are the more practised, but they are not the sole vehicles of function ; and just because they are not, is substitution by new habituations possible. (e)—The Principle of Relative Localisation There can be no doubt that, in a certain sense, the central functions, like those of the peripheral organs, are spatially distinct. But there can also be no doubt that the central organ, as its names implies, represents in con- tradistinction to the peripheral organs a centralisation and thus, at the same time, an unification of functions ; so that any absolute localisation of function, which should confine each separate activity within fixed limits, is a priori impossible, as it is also unsupported by the facts of observation. In the peripheral organs, where the demands of external function have produced diversity of structure, the principle of division of labour is strictly observed, and the localisation of function follows in the train of its observance. In the centres of the nervous system, the principle is broken through in two different ways. On the one hand, every central function divides, and divides the more definitely the higher its place in the ascending series of activities, into a number of subordinate and auxiliary functions, which of themselves embrace wide and, in part, widely remote areas of the central nervous system. On the other, the processes of practice, adaptation and vicarious function show that the spatial centralisation of a function is not fixed, but dependent upon its exercise, and upon the conditions under which this exercise is placed, so that any rigid spatial limitation is out of the ques-