The psychology of visual motion / by Henry J. Watt.

  • Watt, Henry J. (Henry Jackson), 1879-1925.
Date:
1913
Catalogue details

Licence: In copyright

Credit: The psychology of visual motion / by Henry J. Watt. Source: Wellcome Collection.

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

    6/20 (page 30)
    forced explanation given of the results of experiment 28 on page lOT should be consulted. (c) The theory constitutes, as it stands, a lapse from the presumable parallelism of mind and body; it fails to shew that the relations of mind and body, whatever they may be, follow any general scheme or plan ; in fact, it suggests that they vary arbitrarily from one experience to another. For all would agree, I think, that the neural basis of the arrangement of the simplest sensory experiences in respect of their adherent localisations is, proximately or ultimately; the arrangement of neural units of some kind. Of course, we should not expect to be aware of the experiences correlated with these neural units, nor of their localisations, apart from some degree of excitation in these neural units. But neither should we expect to find that the essential aspect of their stimulation, with which alone experience is correlated, is the difference of excitation in them. For even if differ- ence of degree of excitation were a necessary feature of the neural basis of the experience of motion, and of its direction and velocity, these experiences must first and foremost be correlated with the arrangements and interconnexions of the neural units and only secondarily with their difference of excitation. Difference of excitation would, then, be only a means of bringing different localisations with different clearness and insistency to the mind. Thus we might revert to the simple theory of common sense and expect motion to be baced upon the successive stimulation of ne ral units correlated with different positions. And it is to be noted that we have as yet no evidence that bears against this view or shews that the effect of motion is producible from simultaneously stimulated neural units, be they stimulated equally or differently. The facts of the after- effect of seen movement do not, of course, afford this evidence. They offer no other evidence than do the ordinary facts of motion. It is only in the eyes of such a theory as Wohlgemuth’s that the stimulation of the neural units subserving motion is simultaneous and different. [When the stimulation of the elements of a neural complex in different degrees is said to be simultaneous, that means, of course, for Wohlgemuth as for others, simultaneous and continuous over a short stretch of time.] But he extends this explanation not only to the Psychol, lix. 32t: *■ Im Vorbild stimmte die gesehene Bewegung nur nicht dann mit der bereckneten Richtung iiberein, wenn irgendwelche Anhaltspuukte andere Auffassungen begiinstigten,” etc. Compare the effect of using broken lines and spirals, where the seen movement always corresponds to the objective.movement.