Color selection, color capture, and afterimage filling-in

Abstract

R. van Lier, M. Vergeer, and S. Anstis (2009) reported an afterimage that produced different percepts from an inducing stimulus depending on the shape of a subsequent contour. G. Francis (2010) explained this phenomenon with a model where the contour forms a boundary that traps the afterimage color as it spreads across a surface. We conducted a series of additional model simulations and experiments to test the explanation. We first tested the hypothesis that the contour traps the afterimage color by adding additional contours. Model simulations suggest that additional contours could block color from spreading to the middle of the surface. In two experiments, additional contours blocked color spreading when they were at the inducer edges but not when they were drawn away from the inducer edges. In a second set of experiments, we investigated the model prediction that the drawn contour defines the perceived shape of the afterimage. New model simulations predict that variations in the size of the drawn contour force the perceived afterimage to vary accordingly. However, an experimental study revealed that the perceived afterimage size remains the same as the inducing stimulus. The simulation and experimental results both highlight and challenge important characteristics of the model.

Afterimage watercolors: an exploration of contour-based afterimage filling-in

“…Initially, the results from the model were consistent with the idea that boundaries block color spreading. In a second study however, some predictions of the model did not entirely match their experimental data (Kim and Francis, 2011). Particularly, in one instance they used similar star-like stimuli (see Figure 1) as used in van Lier et al (2009), but varied the size of the test outline.…”

“…An alternative interpretation is that the alignment of a test contour with the edges of the inducing colored region is important for filling-in to occur, because of repeated activation of orientation selective neurons that are also coding for color (Friedman et al, 2003). Kim and Francis (2011) additionally found that when the test contour was larger as compared to matching contours, the probability of perceiving filling-in of an unexpected color became higher, possibly due to the fact that larger test contours included afterimages from two complementary colors. However, when the test contour was smaller than the inducing colored region, the probability of perceiving no color filling-in became higher.…”

Luminance contours can gate afterimage colors and "real" colors

“…We should distinguish between the neural site of the afterimages themselves, which are probably in the retina, and of the spatial averaging which happens much later, after the point where motion segregates different regions, namely in or after the cortical area MT. Francis (2009Francis ( , 2010 has suggested that Van Lier et al 's (2009) afterimage filling-in phenomena, although new, can be modeled by earlier ideas (presented in Francis & Ericson, 2004;Francis & Schoonveld, 2005) and by Francis' new simulations of the existing boundary contour system/feature contour system model of visual perception (Grossberg, 2003;Grossberg & Mingolla, 1985a, 1985b, although Kim and Francis (2011) have recently shown that the model cannot explain all phenomena related to the afterimage filling-in effect. Feitosa-Santana, D'Antona, and Shevell (2011) have recently found, as we have, that illusory contours can bound the reach of color fillingin, and Hamburger, Prior, Sarris, and Spillmann (2006) and Hamburger, Geremek, and Spillmann (2012) have studied filling-in of real colors and afterimage colors respectively.…”

Flexible color perception depending on the shape and positioning of achromatic contours

“…These two latter papers also propose that color spreads spatially in a process akin to physical diffusion, until it encounters a luminance contour. The experiments of Kim and Francis ( 2011 ) also showed that their model could not fully account for the spreading of afterimage colors.…”

“…Thus, the superimposed luminance contours modulated the perceived colors: the Gainsborough greyscale made the torso look blue, while the Ingres greyscale made the same torso look pink. With regard to the filling-in of afterimages, Francis ( 2010 ) and Kim and Francis ( 2011 ) explained such contour dependent filling-in effects with a model in which the contour forms a boundary that traps afterimage colors, and presumably real colors, as they spread across a surface. This model in turn draws upon the earlier theories of Grossberg and Mingolla ( 1985 ) and Grossberg ( 2002 ).…”