An alternative perspective on von Winterfeldt et al.'s (1997) test of consequence monotonicity.

D. von Winterfeldt, N.-K.

The peculiar nature of simultaneous colour contrast in uniform surrounds.

We present evidence from asymmetric colour matching experiments which strongly suggests that uniform surrounds evoke induction effects of a very peculiar nature, not representative of colour induction effects in variegated surrounds. Given the widespread use of uniform surrounds in studies of colour vision, this finding is of interest in relation to a number of current research issues, such as contrast coding of colour, functionally equivalent surrounds and colour constancy. A framework that systematises the seemingly complex colour appearance changes induced by uniform surrounds is presented and its implications are discussed.

The natural center of chromaticity space is not always achromatic: a new look at color induction.

Although current theories of color vision differ in many respects, they all assume the existence of a uniquely defined neutral point in chromaticity space. It generally is assumed that this point satisfies several criteria simultaneously. One of these criteria is that it is perceived as achromatic.