Eye movements efficiently expose single cone photoreceptors to global scene color statistics

Our visual experience is a dynamic consequence of our actions, most notably our continuously shifting gaze. These shifts directly influence the spectral input received by individual cone photoreceptors. The present study tested how gaze shifts shape the chromatic diet of single cones and their relationship to global adaptation. Eye movements were recorded from observers freely viewing natural scenes outdoors and from observers freely viewing hyperspectral images of the same scenes indoors on a computer-controlled laboratory display. From the hyperspectral data, spatially local histograms of excitations in long-, medium-, and short-wavelength-sensitive cones were accumulated over time. A simulated global illuminant change was then introduced into the images to test how well local retinal adaptation might discount its effects. Despite the highly non-uniform pattern of natural gaze behavior, the results suggested that individual cones may experience the global color statistics of full scenes within the first several seconds of viewing. This effective sampling could support robust adaptation, allowing local adaptation mechanisms to compensate for illumination changes.