Oculomotor adaptation to wedge prisms with no part of the body seen

When S looks at a visual target through prisms, adaptive shifts in reaching behavior occur even though he sees no part of his body through the prisms. These shifts are caused by a change in the judgment of the direction of gaze (oculomotor change), which in turn is caused by two secondary prismatic effects: (a) asymmetry of the visual display and (b) apparent rotation about a vertical axis of a panel or wall facing S. The “asymmetry” factor contributes 22% of the total oculomotor change, and the “rotation” effect contributes the remaining 78%. Oculomotor change is not facilitated by eye-movement activity. The adaptive oculomotor change induces a non-adaptive proprioception change about one-tenth as large as the oculomotor change. These findings are capable of accounting for the previously unexplained results reported by Wooster in 1923, and also for the current controversy about the role of reafferent stimulation in sensorymotor adaptation.     

Binocular fusion: A test of the suppression theory

Binocular fusion may be due to interocular inhibitory suppression, an hypothesis difficult to evaluate by phenomenal inspection. A test probe method (reaction time to a light pulse) was used to measure visual sensitivity during binocular rivalry and fusion. The absence of inhibitory effects during fusion fails to support the suppression theory of fusion.     

Further experiments on movement masking

Voluntary attention to one of two static objects in the peripheral field of one eye makes this object more liable to masking by a moving object in the corresponding area of the field of the other eye (Experiment 1).

Positive after images (and probably negative after images) are subject to (binocular) movement masking (Experiment 2).

Movement masking can occur in the field of either eye, but with the displays so far tried the inhibitory influence of a moving object is less in the field of the eye to which it is shown than in the field of the other eye (Experiment 3).     

Memory for the pitch of a tone

Observers attempted to detect the presence of a pitch difference between two successive tones. The percentage of correct judgments was equivalent for tones separated by .95, 4.5, and 8.9 sec. There was a general increase in reports of a pitch difference with increased intertone interval, which is interpreted as arising from hypothesized shifts in the neural locus of the first stimulus during the intertone interval.     

Visual and acoustic confusability a visual search task

Visual and acoustic confusability between a target item and background items was varied in a visual search task. Visual confusability was a highly significant source of difficulty while acoustic confusability had no effect. The results do not seem to be interpretable within a theory which assumes compulsory auditory encoding of visual information.     

Oculomotor adaptation to wedge prisms with no part of the body seen

When S looks at a visual target through prisms, adaptive shifts in reaching behavior occur even though he sees no part of his body through the prisms. These shifts are caused by a change in the judgment of the direction of gaze (oculomotor change), which in turn is caused by two secondary prismatic effects: (a) asymmetry of the visual display and (b) apparent rotation about a vertical axis of a panel or wall facing S. The “asymmetry” factor contributes 22% of the total oculomotor change, and the “rotation” effect contributes the remaining 78%. Oculomotor change is not facilitated by eye-movzment activity. The adaptive oculomotor change induces a non-adaptive proprioception change about one-tenth as large as the oculomotor change. These findings are capable of accounting for the previously unexplained results reported by Wooster in 1923, and also for the current controversy about the role of reafferent stimulation in sensorymotor adaptation.