Molyneux's question : vision, touch, and the philosophy of perception / Michael J. Morgan.

  • Morgan, Michael J.
Date:
1977
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Molyneux's question : vision, touch, and the philosophy of perception / Michael J. Morgan. Source: Wellcome Collection.

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    AFTERWORD: RECENT DEVELOPMENTS enee with the defect. The work of Hubel and Wiesel^^ supports this claim in the following manner. First of all, their work had shown that many cells in the visual cortex are driven by units in the two eyes: this convergence of inputs from the tw^o eyes on to single cells is now generally considered to provide the basis for binocular integration. In a cat reared with an artificial squint, how^ever, very few binocular cells were found; the great ma¬ jority of the cells in the visual cortex were driven by one eye only. Mitchell and Ware therefore suggest that a person with suffi¬ ciently severe strabismus should not show any inter-ocular transfer of visual information. To test this idea they made use of the fact that, in normally sighted people, some kinds of visual illusion transfer readily from one eye to the other. They used the tilt after-effect, which consists of a displacement in the orienta¬ tion of a line away from the orientation of a line inspected beforehand. If the inspection line is presented to one eye, and the test line to the other, the displacement of the test line is seen in normally sighted subjects. In three subjects with strabismus, however, Mitchell and Ware showed that there was very little inter-ocular transfer of the effect. They consider that this finding is consistent with the work on cats, amongst which they cite the work of Hirsch. This is puzzling, in view of the fact that Hirsch found excellent inter-ocular transfer in his cats. It is clear that much more behavioural work is necessary before the functional significance of physiological changes can be assessed. The evi¬ dence at present is insufficient to justify a definite decision on Molyneux's question, particularly because the animal experi¬ ments have not been specifically aimed at the problem of trans¬ fer between touch and vision. Section 5: Cross-modal transfer experiments The experimental evidence has been reviewed by Ettlinger,^® D. H. Hubel and T. N. Wiesel, 'Binocular interaction in striate cortex of kittens reared with artificial squint'Journal of Neurophysiology, 28 (1965) 1041-59. G. Ettlinger, 'The transfer of information between sense-modalities; a neuro¬ psychological review' in Memory and Transfer of Information, ed. H. P. Zippel (New York: Plenum Press, 1973] 43-64.1 am grateful to Dr Ettlinger for sending me a copy of his paper, on which the first part of this section is largely based. 191