Contingent Color Aftereffects Research Articles

Mechanisms of perception constancy and recalibration of sensory systems

Possible mechanisms of contingent color aftereffects, in particular, the McCollough effect, are discussed. A hypothesis is proposed, which assumes that the McCollough effect occurs when color constancy mechanisms are activated. Experimental evidence of similarities between the mechanisms of perception constancy and mechanisms of formation of a psychological attitude in terms of the Uznadze theory is demonstrated. Actual activity indicators of recalibration mechanisms of sensory systems are presented using experimentally induced changes in color sensitivity as an example.

The duration of contingent color aftereffects for different directions in color space

The duration of contingent color aftereffects for different directions in color space

Do McCollough effects provide evidence for global pattern processing?

Contingent color aftereffects (CAEs, or McCollough effects) were induced using two pairs of orthogonally related patterns (horizontal/vertical and concentric/radial) to determine whether the CAEs of the four patterns are independent. Tests using composite test patterns (like those employed by Emerson, Humphrey, & Dodwell, 1985) suggested independent aftereffects. However, tests using unitary patterns indicated additive or competing effects of the four patterns in regions where line orientations were similar, and tests isolating such regions showed clear interactions between the pattern aftereffects. The results fail to support the claim that global (rather than local) features of the patterns control these CAEs.

Isoluminance and contingent color aftereffects.

In the typical induction of the orientation-contingent color aftereffect (CCAE), the stimuli are composed of elements that differ in both color and luminance. Three experiments are reported that show that chromatic contrast between stimulus elements is insufficient for the induction of the orientation-CCAE and that luminance contrast is necessary. These experiments expand on previous research concerned with the role of luminance contrast in the induction of orientation-CCAEs by eliminating alternative explanations.

Assessing a new analysis of contingent color aftereffects

Assessing a new analysis of contingent color aftereffects

Contingent color aftereffects: reassessing old conclusions.

Although there is considerable evidence supporting an associative interpretation of contingent color aftereffects, there are data that appear inconsistent with this interpretation. New findings from seven experiments are presented indicating that, contrary to earlier claims, contingent color aftereffects are observed after induction with (1) single orthogonal black bars on colored backgrounds, (2) geometric forms, and (3) two orthogonal grids of the same color. The results of these experiments are relevant to an associative interpretation of contingent color aftereffects, as well as to assessing alternative interpretations of the phenomenon.

Eye movements and the associative basis of contingent color aftereffects: A comment on Siegel, Allan, and Eissenberg (1992).

One of S. Siegel, L. G. Allen, and T. Eissenberg's (1992) recent arguments in support of associative-learning explanations of colored aftereffects (CAEs) is that the contingencies underlying these effects are not constrained by simple stimulus dimensions, such as contour orientation. Specifically, the authors claim to have generated CAEs contingent on sets of spatiotopic relationships between orientation components of a pattern (as opposed to orientation components per se). The present article illustrates how Siegel et al.'s claims are compromised by their failure to adequately address the role of fixation and eye movements during CAE induction.

Scanning and form-contingent color aftereffects.

G. K. Humphrey, A. M. Herbert, L. A. Symons, and S. Kara (1994) and J. Broerse and P. Grimbeek (1994) suggested that the form-contingent color aftereffect reported by S. Siegel, L. G. Allan, and T. Eissenberg (1992) would not be obtained if Ss were instructed to scan the induction and assessment forms. The authors present data from Ss who were instructed to scan the forms. These scanning Ss displayed aftereffects that were no different from those described earlier by Siegel et al. Scanning Ss do display spatiotopic contingent color aftereffects.

Eye movements and the associative basis of contingent color aftereffects: a comment on Siegel, Allan, and Eissenberg (1992).

One of S. Siegel, L. G. Allen, and T. Eissenberg's (1992) recent arguments in support of associative-learning explanations of colored aftereffects (CAEs) is that the contingencies underlying these effects are not constrained by simple stimulus dimensions, such as contour orientation. Specifically, the authors claim to have generated CAEs contingent on sets of spatiotopic relationships between orientation components of a pattern (as opposed to orientation components per se). The present article illustrates how Siegel et al.'s claims are compromised by their failure to adequately address the role of fixation and eye movements during CAE induction.

Effects of spatial filtering and lack of effects of visual imagery on pattern-contingent color aftereffects.

Checkerboards contain fundamental two-dimensional Fourier components oriented 45 degrees from the edges of individual checks. Previous studies have shown that contingent color aftereffects following adaptation to chromatic checkerboard stimuli were associated with the fundamental components rather than the edges. In the present experiments, we measured contingent color aftereffects, using the method of constant stimuli, after subjects adapted to unfiltered checkerboards and checkerboards with the fundamental Fourier components removed. The adaptation stimuli were magenta (or green) squares and green (or magenta) diamonds; the test stimuli were vertical or oblique sine-wave gratings with different saturations. After adaptation to unfiltered checkerboards, aftereffects contingent on the fundamental components were obtained. In contrast, after adaptation to filtered stimuli, aftereffects of smaller magnitude were found to be aligned with the edges. The data support the previous findings of spatial-frequency-contingent color aftereffects with checkerboard adaptation stimuli and indicate that the aftereffects can be associated with edges if the fundamental components of adaptation stimuli are removed by spatial filtering. We reexamined the possibility of color aftereffects induced by imagery of checkerboards. Contrary to the previous reports, no significant aftereffects were obtained.

Spatial-frequency-contingent color aftereffects: adaptation with one-dimensional stimuli.

The McCollough effect was shown to be spatial-frequency selective by Lovegrove and Over (1972) after adaptation with vertical colored square-wave gratings separated by 1 octave. Adaptation with slide-presented red and green vertical square-wave gratings separated by 1 octave failed to produce contingent color aftereffects (CAEs). However, when each of these gratings was adapted alone, strong CAEs were produced. Adaptation with vertical colored sine-wave gratings separated by 1 octave also failed to produce CAEs, but strong effects were produced by adaptation with each grating alone. By varying the spatial frequency of the test sine wave, CAEs were found to be tuned for spatial frequency at 2.85 octaves after adaptation of 4 cycles per degree (cpd) and at 2.30 octaves after adaptation of 8 cpd. Adaptation of both vertical and horizontal sine-wave gratings produced strong CAEs, with bandwidths ranging from 1.96 to 2.90 octaves and with lower adapting contrast producing weaker CAEs. These results indicate that the McCollough effect is more broadly tuned for spatial frequency than are simple adaptation effects.

Spatial-frequency-contingent color aftereffects: adaptation with two-dimensional stimulus patterns.

The spatial-frequency theory of vision has been supported by adaptation studies using checkerboards in which contingent color aftereffects (CAEs) were produced at fundamental frequencies oriented at 45 degrees to the edges. A replication of this study failed to produce CAEs at the orientation of either the edges or the fundamentals. Using a computer-generated display, no CAEs were produced by adaptation of a square or an oblique checkerboard. But when one type of checkerboard (4 cpd) was adapted alone, CAEs were produced on the adapted checkerboard and on sine-wave gratings aligned with the fundamental and third harmonics of the checkerboard spectrum. Adaptation of a coarser checkerboard (0.80 cpd) produced CAEs aligned with both the edges and the harmonic frequencies. With checkerboards of both frequencies, CAEs were also found on the other type of checkerboard that had not been adapted. This observation raises problems for any edge-detector theory of vision, because there was no adaptation to edges. It was concluded that spatial-frequency mechanisms are operating at both low- and high-spatial frequencies and that an edge mechanism is operative at lower frequencies. The implications of these results are assessed for other theories of spatial vision.

The associative basis of contingent color aftereffects.

According to a conditioning analysis of the orientation-contingent color aftereffect (McCollough effect, ME), orientation stimulus (grids) become associated with color. Contrary to this interpretation are reports that simple forms cannot be used to elicit illusory color and that the ME is not degraded by decreasing the grid-color correlation. The present results indicate: (a) Form stimuli can contingently elicit color aftereffects; (b) even a non-patterned stimulus--the lightness of a frame surrounding a colored area--can contingently elicit color aftereffects; (c) this frame lightness-contingent aftereffect, like the ME, persists for at least 24 hr; and (d) the frame lightness-contingent aftereffect can be used to demonstrate that correlational manipulations affect the ME, as they affect other types of conditional responses.

The associative basis of contingent color aftereffects.

The associative basis of contingent color aftereffects.

Characteristics of the indirect McCollough effect

Induction of contingent color aftereffects with a single chromatic grid sometimes results in an illusory color on a grid different from the one presented during induction. Such illusory color, contingently elicited by a noninduced grid, has been termed the indirect McCollough effect (indirect ME). We show that the indirect ME occurs only when the color complementary to the grid color is present during induction (either physically present or as a color afterimage), and that the indirect ME is seen only on gratings that are orthogonal to the induction orientation. These findings are in accord with the account of the indirect ME proposed by Humphrey, Dodwell, and Emerson (1989). We also show that characteristics of the indirect ME (seen following one-grid induction), both on induced and orthogonal orientations, are similar to those observed with the direct ME (seen following the usual two-grid induction procedure). Both procedures result in contingent aftereffects that display substantial retention and that do not display interocular transfer.

Color aftereffect contingent on text.

During adaptation, two different letter strings (each five or six letters) were presented to subjects alternately, one in green and the other in magenta. The extent to which these letter strings subsequently elicited a color aftereffect was assessed. In different experiments, the chromatic letter strings consisted of words and nonwords. The results indicated that letter strings that form English words can contingently elicit a color aftereffect. This was the case even when the words were anagrams. There was no evidence that nonword letter strings could contingently elicit such an aftereffect, even when the nonwords conformed to English orthography. The results are relevant to understanding other contingent color aftereffects (McCollough effects), illusory color noted by computer operators who work at monochrome (green or amber) displays, and the processing of text.

Age-related differences in the magnitude of pattern-contingent color aftereffects.

Pattern contingent color aftereffects were measured using a color cancellation technique in 6-, 8-, 10-, and 20-year-old subjects. Postadaptation test conditions involved immediate testing or testing after subjects were blindfolded for 60 min between adaptation and posttests. The 6- and 8-year-old subjects exhibited color aftereffects whose magnitude was significantly greater than those observed in 10- and 20-year-olds. In addition, aftereffect magnitude was significantlygreater after 60 min in the dark than when subjects were tested immediately. These findings are discussed in terms of their implications for the development of perceptual learning.

Orientation-contingent color aftereffects: Retinal specificity

Hayman and Allan (1980) concluded that the color aftereffects they obtained were orientation contingent rather than angle contingent, and they argued that these orientation-contingent color aftereffects were retinally specific. Additional data in support of the Hayman and Allan (1980) conclusion are reported. These data point to the important role of eye fixations and eye movements on contingent color aftereffects.

Imagery-induced McCollough effects: real or imagined?

Recently, this journal published two studies, one by Broerse and Crassini (1980) and one by us (Kunen & May, 1980), that report contradictory findings on whether visual imagery can be used to induce contingent color aftereffects (CABs). We found, using a color-cancellation procedure, that CAEs could be produced from adaptation to visual imagery. These findings replicate and extend earlier findings of imagery-induced CABs reported by Finke and Schmidt (1977, 1978). In contrast, Broerse and Crassini (1980), using a forced-choice verbal report paradigm, report that no CABs could be obtained from adaptation to visual imagery and that interocular transfer of CAEs did not occur. 1 Finke (1981), in commenting on these articles, suggests that the failure of Broerse and Crassini to find CABs after adaptation to visual imagery might have reflected their use of a forced-choice method of measuring CABs. We also suspect that their failure to find imagery-induced CABs might have resulted from the particular method they employed. Broerse and Crassini told subjects that subsequent to adaptation they would view a test slide and would have to judge whether the test slide contained color and, if color was present, to rate the degree to which the color was present. Such a procedure may have enabled subjects to easily perceive a relationship between the study and test phases and to try to secondguess the experimenters. For example, after imagining patterns, the subjects may have figured out that there was no objectively present color in the test slides and may have felt that they were being tested for the extent to which they could be coaxed into believing that colors were present. In our colorcancellation procedure, it was virtually impossible for naive subjects to guess what our experimental hypotheses were or to see any relationship between the color-cancellation adjustments and the patterns in their imagery. Also, the color-cancellation procedure may measure CAEs more directly than verbal reports and thus may be a more sensitivemethod, The results of our study indicated that visual imagery can be a source of visual stimulation that induces CABs. Furthermore, the direction of the CAEs derived from imagery was opposite to the direction of CABs resulting from adaptation to well-focused externallypresent stimuli. Sinceit is well established that, with adaptation to checkerboard patterns of 3.0 c/d, CABs are derived from adaptation to the funda-

Further Evidence for Conditioning Processes in the McCollough Effect

Summary McCollough effects (pattern contingent color aftereffects) were obtained in a series of three experiments designed to examine the possibility that a learning (conditioning) process underlies these effects. In Experiment 1, ordinary McCollough effects appeared after viewing adaptation patterns that were spatially separated from adaptation colors. In Experiment 2, patterns and colors were presented separately in different temporal orders during adaptation; the normal McCollough effect was obtained when adaptation patterns immediately preceeded their associated colors, but reversed McCollough effects were obtained when colors preceeded patterns. Experiment 3 demonstrated that the McCollough effect is more readily acquired on successive acquisition trials. Three practiced observers were used throughout; a fourth, a naive observer was added in Experiment 3. The results are interpreted as evidence that McCollough effects involve a learning process. The importance of learning in sensory information proce...