Thesis (Ph. D.)--University of Michigan, 1941. / Reprinted from the Journal of experimental psychology, vol. 33, no. 5, November, 1943. Bibliography: p. 406.

Thesis (Ph. D.)--University of Chicago, Dept. of Psychology Committee on Biopsychology, December 1993. / Includes bibliographical references.

Thesis (M.A.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1961. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2005. / Available online via OhioLINK's ETD Center; full text release delayed at author's request until 2008 May 31

Thesis (Ph. D.)--University of Chicago, Dept. of Psychology Committee on Biopsychology, December 1993. / Includes bibliographical references.

1. The eyes of the crab Carcinus follow with constantly increasing lag the movement of a horizontally rotating (but not a linearly translated) visual field during the slow phase of optokinetic nystagmus. The difference between the eye speed and the drum speed is the effective stimulus for optokinetic nystagmus, and the response bears a constant relation to the stimulus over four orders of magnitude. The lower limit of the response is due to the breakdown of neuromuscular, and not visual mechanism. 2. An overall feedback mechanism exists in which the movement of the eye reduces the apparent movement of the drum. The control of the eye movement is by way of visual cues and proprioceptors play no part. 3. A seeing eye, provided with the appropriate visual stimulus, will drive the other eye if the latter sees no contrasting objects in its visual field or is blinded. Clamping an eye so that it cannot move relative to a stationary, contrasting visual field has the same effect as surrounding the animal with a blank field. 4. The rapid return phase of optokinetic nystagmus also takes no account of proprioceptors, but seems to be triggered when the efferent impulses to the eye muscles reach a definite frequency. Blinding one eye or increasing the drum speed cause a delay of the fast phase. Both eyes flick back simultaneously and the impulses in the oculomotor nerve which cause the slow phase are inhibited during the fast phase. 5. The fast protective retraction of the eye into its socket is a reflex which can be elicited by mechanical stimulation of a single sensory hair. The eyes can retract independently and if retraction occurs during the slow phase of optokinetic nystagmus, the efferent impulses in the oculomotor nerve of the retracting side are centrally suppressed. Peripheral inhibition of the optokinetic response occurs in the retracted eye when it. Is retained in its socket after retraction while the other eye continues with the slow phase of optokinetic nystagmus.7. A comparison reveals similarities in the mechanism causing the onset of the fast phase of optokinetic nystagmus in the crab and in mammals.

Previous attempts to adequately evaluate orientation-specific colored aftereffects (Mccollough Effects) have thus far been unsuccessful in yielding quantitative measures of relative strengths of the effects. Similarly, little success has been shown in previous attempts to establish what level of illumination is necessary in order to evoke the aftereffects. The present study sought to determine (a) whether threshold measurements could serve as adequate, quantitative dependent variables of the Mccollough Effects, (b) whether photopic illumination was necessary in order to evoke the aftereffect. It was predicted that the greater the number of inspection trials, the dimmer the illumination level could be in order for the aftereffects to first be detected. In addition, it was· predicted that the appearance of the test pattern would change markedly near the rod-cone break. The strength of the McCollough Effects, as a function of the number of inspection trials, was examined on subsequent scotopic and photopic threshold measurements in normal color-visioned subjects. All subjects were measured alternately on 10 ascending and 10 descending trials at specific times after being conditioned in "short" (15 min) and "long" (30 min) inspection trials, counterbalanced across subjects, with a 7-day interval between test trials. Overall, statistically insignificant results were achieved for both predictions; possible explanation of the results and changes in experimental design were discussed.

The McCollough Effect is an orientation specific colored aftereffect. That is, following prolonged viewing of a vertical grid on orange ground alternated with a horizontal grid on blue ground, a yellow-orange hue is perceived on an achromatic horizontal grid, and a bluish hue on a vertical grid. McCollough suggested that the colored aftereffect may depend upon color adaptation of a population of neural elements specific to colored edges of a particular orientation. Accordingly vertical edge detectors sensitive to orange adapt during inspection such that when vertical edges are presented on an achromatic ground only those non-adapted color-line detectors respond creating the perception of blue. Similarly, horizontal edge detectors specific to blue adapt such that response to achromatic edges creates the perception of yellow-orange. In a subsequent study McCollough and Clark used left and right diagonal inspection patterns and observed that the aftereffect of orange and right diagonal was influenced by the left diagonal color that was alternated with it. The aftereffect of orange right diagonal tended toward blue when the orange stimulus was alternated with a blue left diagonal stimulus pattern and tended toward green when the orange stimulus was alternated with a green left diagonal pattern. On the basis of the color coded edge detector theory McCollough and Clark suggested the effect was induced by wavelength adaptation of wavelength sensitive edge detectors which may influence the hue of the• aftereffect on the orthogonal test pattern. A test of McCollough's model of color coded edge detectors was made by presenting a colored field (no lines) to S before the presentation of the color-line stimulus. If wavelength and edge stimuli were processed by a population of neural elements sensitive to both, then the aftereffect would not be affected by the presentation of an unlined color field. If color and line stimuli were processed separately, then the "effective" color component of the lined stimulus pattern would be that portion of the spectrum not stimulated by the preceeding color field. The color of the aftereffect would be approximately complementary to the non-adapted population of color receptors stimulated by the lined inspection pattern. In the experiment 28 college juniors observed two inspection conditions. In condition 1 orange vertical alternated with blue horizontal and the aftereffect created was measured via a colorimeter. The same stimulus patterns were employed in condition 2 where each was preceeded by a plain color field that stimulated a portion of the spectrum illuminated by the following lined stimulus. The aftereffect observed was compared with the aftereffect on condition 1. Color matches were measured by three photometer readings indicating percent transmittance of red, blue, and green in each match. These readings were translated into CIE x, y coordinates and the means plotted on a chromaticity diagram. Statistical analysis of the data indicated that the color matches in condition I and condition 2 were significantly different and varied as predicted. While McCollough and Clark attributed the variation in the hue of the colored aftereffect to the relative spectral properties of the lined inspection patterns employed in their experiment, the present study shows that the results may be due to the state of color adaptation resulting from the preceeding stimulus pattern. The adapting color stimulus is not necessarily a lined color pattern. It may indeed be a plain color field. The results suggest that the colored line-contingent aftereffect is created by at least two levels in the visual system: color receptors independent of slope analysers. The color coded edge detector model is not adequate to account for the McCollough Effect.

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