Systematic biases in adult color perception persist despite lifelong information sufficient to calibrate them

Abstract

Learning from visual experience is crucial for perceptual development. One crucial question is when this learning occurs and to what extent it compensates for changes in the visual system throughout life. To address this question, it is essential to compare human performance not only to the hypothetical state of no recalibration, but also to the ideal scenario of optimum learning given the information available from visual exposure. In the adult eye, macular pigment introduces nonhomogeneity in color filtering between the very center of vision and the periphery, which is known to introduce perceptual differences. By modeling cone responses to the spectra of everyday stimuli, we quantify the degree of calibration possible from visual exposure, and therefore the perceptual color distortion that should occur with and without recalibration. We find that perceptual distortions were halfway between those predicted from bare adaptation and from learning, despite nearly lifelong exposure to a very systematic bias. We also show that these distortions affect real stimuli and are already robust in the near-periphery. Our findings challenge an assumption that has fueled influential accounts of vision-that the apparent homogeneity of perceived colors across the visual field in everyday life is evidence for continuous learning in perception. Since macular pigment is absent at birth and reaches adult levels before age 2, we argue that the most plausible, though likely controversial, interpretation of our results is early development of color constancy across space and not much recalibration afterwards.

Probing the functions of contextual modulation by adapting images rather than observers

“…This illustrates a case where modeling specific forms of adaptation can be used to reveal the presence of additional compensatory processes. (The studies of Bompas et al (2013) and O’Neil and Webster (2014) also draw attention to the finding that this compensation is not perfect, yet the residual errors reflect very minor deviations relative to the enormous degree of constancy already afforded by von Kries scaling, which again underestimates the level of constancy observed. )…”

“…Third, color percepts are in fact more stable than predicted by multiplicative gain changes in the receptors, which can discount most but not all of the spectral shifts from an illuminant change or a change in prereceptoral screening pigments (Bompas, Powell & Sumner, 2013, O'Neil & Webster, 2014, Webster, Halen, Meyers, Winkler & Werner, 2010a). This illustrates a case where modeling specific forms of adaptation can be used to reveal the presence of additional compensatory processes.…”

Visual Adaptation

“…Perceived focus is largely corrected for the optical aberrations of the eye, but for higher-order aberrations is more effectively adjusted to the magnitude than the specific blur pattern (Sawides et al, 2012). Compensation of color appearance for lens and macular pigment is better than predicted by adapting to the average color alone – suggesting it goes beyond independent gain changes in the cones – but residual errors remain (Bompas et al, 2013, O'Neil and Webster, 2014). An interesting example of the limits of adaptation for color perception is anomalous trichromats.…”

Filling in, filling out, or filtering out: processes stabilizing color appearance near the center of gaze

“…In the same way, screening the light with a filter like macular pigment could not be compensated only by rescaling the average sensitivity of each cone. The finding that color constancy was actually better than von Kries scaling implies that additional mechanisms contribute to the stability of color appearance across the visual field [11,14] and argues against suggestions from hue cancellation experiments that only some dimensions of color coding are compensated for macular screening [15–17]. Candidate cell types that could promote constancy beyond photoreceptor adaptation, such as double-opponent receptive fields, have been considered in a wide variety of studies (e.g., [18–22]).…”

“…However, Bompas et al [14] subsequently focused on comparing the color appearance of purple and more saturated surfaces, where any effects of macular pigment should be greatest. They also found that color appearance was more stable than would be predicted by average gain changes in the foveal and peripheral cones.…”