Boys with peer adjustment problems: social cognitive processes.
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Child↗
Biomedical subjects
J W Callan
Publications and source records attributed to J W Callan.
Directional changes in the vestibular ocular response as a result of adaptation to optical tilt.
Before and after exposure to clockwise optical tilt, subjects' compensatory eye movements were recorded, as the head was oscillated around a vertical axis by the experimenter. An analysis of the horizontal and vertical components of eye movements showed a change in eye movement path in the clockwise direction. This corresponded to similar changes in visual spatial orientation judgments indicative of perceptual adaptation. It was suggested that long-term visual feedback serves to restore the compensatory nature of the eye movements which was altered by the introduction of the prism transformation.
Adaptation, Ocular↗
Tilt adaptation as a feedback control process.
Adaptation to optical tilt was analyzed with time-varying input signals in the form of step, ramp, and triangular wave-form functions. Step-function transients appeared to stabilize at about 15 min, suggesting a time constant of 4-5 min. Gain decreased with input rate beyond about 1.4 degrees min-1 and with input amplitude. In all instances gain was considerably less than one. The frequency of the triangular waves was relatively faithfully reflected in the output, but the wave form was distorted by the uneven influence of clockwise over counter-clockwise inputs. A control system with output proportional to error and an exponential delay was proposed as a model of tilt adaptation. The relationship to adaptation of the vestibulo-ocular response also is discussed.
Adaptation, Psychological↗