Licence: In copyright
Credit: Attention / by W.B. Pillsbury. 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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![of such an inhibition in a comparatively low vertebrate is the experiment of Mobius [7] repeated by Dr. Triplett [I3] upon the perch. It was found that if a minnow and a perch were put in the same tank but separated from each other by a pane of clear glass, the perch would at first make many vain attempts to seize the minnow and would strike its head against the pane in its struggles. In a comparatively short time, however, it would discover that the endeavour was useless and would give up the struggle. The most surprising thing from the human standpoint is that when the glass was removed and the two fish were permitted to swim together in the same space, the perch still made no attempt to devour its natural prey. Here, frequent ex- periences had overcome the inherited impulse, the normal association of movement with visual impression was de- stroyed. This is an effect very similar to the inhibition which the electric current exerted on the perception of the grey lines on the Masson disc in Mr. Taylor’s experiments, except that it affects the motor connections as well as the sensory. Probably, however, the effect of one sensory im- pression upon another would appear at the same time, for, as we have seen, the control of the movement is in terms of a sensory process of some kind, and one inhibition would make its appearance at very much the same place as the others. Of course the difference in degree between attention at these lower stages of development and that which we see in man is so great as to amount almost to a difference in kind. To take even a fairly highly developed animal like the perch, we find that only one aspect of the experience with the minnowhas any influence upon the later action—its unattain- ableness. In man other phases would have entered as well. He would have seen that the minnow was only unapproach-. able as long as the glass intervened, or as long as it was at the other end of the tank. Development of attention from this standpoint consists very largely in the addition of new elements success vely to modify the one element which](https://iiif.wellcomecollection.org/image/b21523630_0320.jp2/full/800%2C/0/default.jpg)
