Fatigue and its effects upon control / by Isaac Emery Ash.

  • Ash, Isaac Emery.
Date:
1914
Catalogue details

Licence: Public Domain Mark

Credit: Fatigue and its effects upon control / by Isaac Emery Ash. Source: Wellcome Collection.

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    principle was rather tritely expressed by one of the observers in the foregoing experiments. In discussing spontaneous reversals she said: ‘‘T hardly believe they are spontaneous; I know there is another view of the figure and I also know how to get it, and I can’t help looking for it.’? The principle is somewhat analogous to that in- volved if one were to give a toy to a child and tell him at the same time that he had something else for him. He would no sooner be in possession of the first than he would be, not only willing, but ex- tremely anxious to relinquish it in order to secure the second. My own view of the general character of the process agrees more nearly with that of Woodworth than with any of the others; al- though I am unwilling to concede that mental imagery plays no part. It is altogether probable that practised observers, and others whose mental processes or mental reactions are more direct will be able to dispense with images and deal with the figures in terms of their own features or characteristics, while others will find them indispensable in determining the kind of ‘‘mental reaction’’ which the figures shall call forth. The same principle is involved here as in learning to read a new language. The beginner can interpret words in the new language only as they suggest words of like meaning in his own. But with continued practise he is able eventually to omit this intermediate step and interpret the language directly. One of our observers in discussing the reversal of the Scripture blocks said that her chief difficulty in ‘‘making them change’’ was ‘‘while looking at them one way I can’t think of anything they will look like when I see them the other way.’’ Another evidence that imagery was employed by a large number of the subjects, espe- cially those unfamiliar with the reversals was the fact that it was very often necessary, in pointing out the different perspectives, to use real objects, such as a box for the cube or a real stair for the stair figure. The fact that different mental reactions are possible to the same figure means that it is capable of stimulating to activity different centers of the brain. That is, the sensory excitation caused by the figure as a visual stimulus may reach either of two brain centers, and the perspective with which the figure is seen will depend on which centers are active. The observer’s ability to determine arbi- trarily just which perspective he will have depends upon his ability to control the direction of this nervous excitation. A large num- ber of aids are of course possible in accomplishing this. Any- thing which causes a heightened activity.in one center and lessens the activity of the other will bring about the appropriate mental response.
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