Harvard Psychological Studies, Volume 1 eBook

This eBook from the Gutenberg Project consists of approximately 757 pages of information about Harvard Psychological Studies, Volume 1.

Harvard Psychological Studies, Volume 1 eBook

This eBook from the Gutenberg Project consists of approximately 757 pages of information about Harvard Psychological Studies, Volume 1.

This explanation of Graefe is not to be admitted, however, since in the case of eye-movement there are muscular sensations of one’s own activity, which are not present when one merely sits in a coach.  These sensations of eye-movement are in all cases so intimately connected with our perception of the movement of objects, that they may not be in this case simply neglected.  The case of the eye trying to watch its own movement in a mirror is more nearly comparable with the case in which the eye follows the movement of some independent object, as a race-horse or a shooting-star.  In both cases the image remains on virtually the same point of the retina, and in both cases muscular sensations afford the knowledge that the eye is moving.  The shooting-star, however, is perceived to move, and the question remains, why is not the eye in the mirror also seen to move?

F. Ostwald[7] refutes the explanation of Graefe from quite different considerations, and gives one of his own, which depends on the geometrical relations subsisting between the axes of vision of the real eye and its reflected image.  His explanation is too long to be here considered, an undertaking which indeed the following circumstance renders unnecessary.  While it is true that the eye cannot observe the full sweep of its own movement, yet nothing is easier than to observe its movement through the very last part of the arc.  If one eye is closed, and the other is brought to within about six inches of an ordinary mirror, and made to describe little movements from some adjacent part of the mirror to its own reflected image, this image can almost without exception be observed as just coming to rest.  That is, the very last part of the movement can be seen.  The explanation of Ostwald can therefore not be correct, for according to it not alone some parts of the movement, but absolutely all parts alike must remain invisible.  It still remains, therefore, to ask why the greater part of the movement eludes observation.  The correct explanation will account not only for the impossibility of seeing the first part of the movement but also for the possibility of seeing the remainder.

   [7] Ostwald, F., Revue Scientifique, 1896, 4e Serie, V., p.
   466.

Apart from the experience of the eye watching itself in a glass, Dodge (loc. citat.) found another fact which strongly suggested anaesthesia.  In the course of some experiments on reading, conducted by Erdmann and Dodge, the question came up, how “to explain the meaning of those strangely rhythmic pauses of the eye in reading every page of printed matter.”  It was demonstrated (ibid., p. 457) “that the rhythmic pauses in reading are the moments of significant stimulation....  If a simple letter or figure is placed between two fixation-points so as to be irrecognizable from both, no eye-movement is found to make it clear, which does not show a full stop between them.”

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Harvard Psychological Studies, Volume 1 from Project Gutenberg. Public domain.