Contour specificity of the McCollough effect

Subjective estimates of McCollough aftereffect strength are significantly reduced when certain spatial features of the line grating patterns are manipulated. Results are dependent upon whether the spatial parameters of the test or inspection patterns are altered. Changing the angular slant, contour sharpness, or contour completeness of the inspection gratings does not affect aftereffect strength, but changing the spatial frequency, contour sharpness, or contour completeness of the test gratings does. The implications of these results are discussed with regard to theories offered to explain the McCollough effect.