Beer, R.D. and MacLeod, D.I.A. (2000) Pre-exposure to contrast selectively compresses the achromatic half-axes of color space. Vision Research, in press.

    The gamut of perceived colors can be represented in a space with bright-dark, red-green, and blue-yellow axes. Pre-exposure to a field that changes periodically over time in luminance or along one of the color axes reduces vividness of colors along the entire axis (Webster and Mollon, 1991). But is it possible to reduce vividness or perceived contrast selectively for half-axes in color space? We assessed such selective compression of the bright-dark axis using a task where subjects matched tests in a pre-adapted region to ones in an un-adapted region. Tests were bright or dark pinstripes on a gray background, and pre-exposure was to multiple drifting pinstripes. Matches made after pre-exposure indicate a combination of symmetric and asymmetric compression, with more compression when adapting and test stimulus were similar in contrast polarity.