Abstract
PURPOSE: Misbinding of color occurs when the neural representation of color from a suppressed form is expressed within some region of the dominant form. In previous work, misbinding of color always was perceived within achromatic (gray) regions of the dominant form (Hong & Shevell, 2006). Misbinding of perceived gray into red or green regions never was seen. Are colors (e.g. red and green) misbound only to achromatic regions that represent the absence of color (achromatic hypothesis), or instead to regions with a stimulus chromaticity most similar to the misbound color (similarity hypothesis)?
METHOD: For 60 seconds, an equiluminant 2 cpd square-wave vertical grating was presented to one eye and a tooth-shaped vertical grating (top half of grating phase-shifted by one-half cycle relative to bottom half) to the other eye. Conditions included (A) a red/gray grating in one eye and green/gray grating in other eye (as in previous work) or (B) a red/orange grating in one eye and green/orange grating in the other eye. Measurements were made of the amount of time with the percept of one eye's stimulus alone (dominance), and with a two-color-grating percept with color misbinding seen in an achromatic stimulus region (e.g. green misbound to gray stimulus region in A), or in a chromatic stimulus region (e.g. green misbound to an orange stimulus region in B).
RESULTS & CONCLUSIONS: Misbinding was perceived within both achromatic regions and within chromatic orange regions. Further, with red/orange and green/orange rivalrous gratings, red more often than green was misbound to an orange region. This is consistent with the similarity hypothesis. However, misbinding of perceived orange into red or green regions, to form a uniform orange field, never was seen; one possible explanation is that the edge structure must be preserved after misbinding of color to form.
Supported by NIH grant EY-04802.