Characteristics of the indirect McCollough effect

Area of Science:

• Visual perception
• Color vision
• Psychophysics

Background:

• Contingent color aftereffects, like the McCollough effect (ME), demonstrate how visual experience can be altered by prior stimulation.
• The indirect ME is a variation where illusory color appears on a non-presented grid, posing questions about its underlying mechanisms.

Purpose of the Study:

• To investigate the conditions and characteristics of the indirect McCollough effect (indirect ME).
• To determine the role of complementary colors and grating orientation in the indirect ME.
• To compare the indirect ME with the direct ME.

Main Methods:

• Presenting a single chromatic grid for induction of color aftereffects.
• Testing for illusory color perception on differently oriented gratings.
• Comparing results with established findings for the direct ME.

Main Results:

• The indirect ME requires the presence of complementary colors during induction (physical or afterimage).
• Illusory color in the indirect ME is observed exclusively on gratings orthogonal to the induction orientation.
• The indirect ME shares characteristics with the direct ME, including retention and lack of interocular transfer.

Conclusions:

• The findings support Humphrey, Dodwell, and Emerson's (1989) model of the indirect ME.
• The indirect ME is a contingent visual aftereffect with properties similar to the direct ME.
• Both direct and indirect ME demonstrate robust memory and are not subject to binocular rivalry.