An examination of colour-contingent pattern aftereffects.

The McCollough effect (ME) is an example of a pattern-contingent colour aftereffect. This study describes some characteristics of another visual aftereffect linking pattern and colour here called a colour-contingent pattern aftereffect (CCPA). After inducing with, for example, a magenta and black radial pattern and a green and black pattern of concentric circles, presentation of a green homogeneous field evoked a faint image of a radial pattern superimposed on the field, whereas presentation of a magenta homogeneous field produced a faint image of concentric circles. The pattern was blurred and fleeting, occurring with the onset of the homogeneous field, but nevertheless was evoked reliably. Various properties of these colour-contingent pattern aftereffects are reported. Although the aftereffects have some of the characteristics of the ME, the CCPA is not as long lasting as the ME, and, unlike the usual ME, it is abolished if eye-movements are made during induction.