Effect of spatial uncertainty and familiarity on memory for surface colour in natural scenes and Mondrian patterns

How does memory affect surface-colour matching and is there any advantage with familiar scenes? A computer-controlled colour display system was used to present images of natural scenes and Mondrian patterns under two different daylights of correlated colour temperatures 25000 K and 6500 K, each lasting 1 s and separated by an interval lasting 0, 0.1, 0.2, 0.5, 1, 2, or 5 s, with a gradual transition from the first to second image. For natural scenes, one mainly vegetated, the other mainly non-vegetated, the test surface to be matched was a coloured sphere at a fixed location in the scene. For Mondrian patterns, which were either generated afresh from trial to trial or constant throughout the experiment, there was either a single test surface at the centre of the pattern or multiple test surfaces distributed randomly over the pattern. Observers had to decide whether the test surface or surfaces had the same colour over the time course of the stimulus. Performance, measured by a colour-constancy index, was stable with natural scenes and with constant Mondrian patterns, independent of the interval duration. With freshly generated Mondrian patterns, performance was almost constant for intervals up to about 1 s with a central test surface but worsened rapidly with randomly distributed test surfaces. It seems that surface-colour matching is not limited by memory, at least over intervals of seconds, but it is influenced by uncertainty in the spatial organisation of stimuli and the location of the test surface.