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Experiment Author: Susan Campbell. Adapted from STEP and used with permission of Brian MacWhinney
This experiment shows participants alternating blue fields with horizontal stripes and orange fields with vertical stripes. The edge detectors then adjust to compensate, and participants see orange color behind all horizontal edges and blue color behind all vertical edges. This is also known as the McCollough Effect, for obvious reasons.
Participants concentrate on alternating images. The images will be patterns of horizontal and vertical lines with differing colors. Participants can press any key on a keyboard to move to the next image. A prompt will ask participants to report if they see afterimages. A keyboard is used to collect responses.
McCollough, C. (1965). Color Adaptation of Edge-Detectors in the Human Visual System. Science, 149, 1115-1116.
Cited Experiment Abstract
An after-effect of color which depends on the orientation of lines in the test field may be obtained by presenting a horizontal grating of one color alternately with a vertical grating of a different color. Like the aftereffect of adaptation to chromatic fringes produced by prismatic spectacles, this aftereffect is visible in monochromatic light and fails to show interocular transfer. It is suggested that both effects are to be understood in terms of color adaptation of orientation-specific edge-detectors.