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Biomedical subjects

I E Gordon

Publications and source records attributed to I E Gordon.

9 recordsLinked to original sources

Perceived causality occurs with stroboscopic movement of one or both stimulus elements.

It was shown by magnitude estimation that the perception of causality first described by Michotte (1946/1963) also occurs consistently and strongly with stroboscopic, ie apparent or phi, movement. This is so when the 'causal' movement is stroboscopic and the 'caused' movement real, when these movements are reversed, and when both movements are stroboscopic. The effect is not due to prior experience with Michotte-type displays.

Adult

A possible explanation as to why the newly sighted commonly perform well on pseudoisochromatic colour vision tests.

Patients whose vision has been restored after long periods of blindness commonly experience difficulty in perceiving. Parodoxically, such patients often perform well on pseudoisochromatic colour-vision tests. A well-known example is Gregory and Wallace's subject, S.B. who performance on the Ishihara test was perfect. It is suggested that restoration of vision may be associated with relatively poor visual acuity and that this, by filtering higher spatial frequencies, enhances the legibility of pseudoisochromatic test patterns. Two experiments confirm that the Ishihara plates are more legible when seen as defocused images.

Blindness

Electroretinographically determined spectral sensitivity in the tawny owl (Strix aluco).

The electroretinographic (ERG) responses to single light flashes and to flickering lights were obtained in the tawny owl (Strix aluco). The waveform of the single-flash responses indicated that the owl possesses a duplex retina. Spectral sensitivity was determined with light flickering at a 6 and 25 Hz. The sensitivity curve obtained from the 6-Hz responses has a broad maximum between 500 and 525 nm. The 25-Hz sensitivity curve is narrow with a peak at about 600 nm. The sensitivity curves are compared with behaviorally measured sensitivity curves of the pigeon. A close agreement is found between 25-Hz curve and the pigeon red modulator.

Animals