Figure 6.

Data from the global condition. Colour constancy index C, calculated along a vector joining the steady-state achromatic points for the two illuminants, plotted against number of trials since an illuminant shift t (2.1s inter-trial interval). The colour of the symbols and lines represents the illuminant chromaticity relative to which the constancy index was calculated: sunlight (yellow) or skylight (blue). Filled symbols indicate the constancy index calculated relative to the illuminant chromaticity used on that trial, and open symbols represent the index calculated relative to the other illuminant, for comparison. The shaded regions of the plot indicate the time-course of the illuminant switch: sunlight (yellow) or skylight (blue). Presentations are labelled such that A_n is the nth trial after a change in simulated illuminant to sunlight, and B_n is the nth trial after a change in simulated illuminant to skylight.