Seasonal changes can affect human color perception

Telegraph : Of all the colors humans see, just four—red, yellow, blue, and green—are considered to be unique, meaning they are not a mix of several colors. However, perception of even those unique colors can vary among individuals due to the physiology of the retina and aging of the eye. Although of the four colors, yellow appears to be the most reliably identifiable across large populations, even it can vary, say researchers whose study has been published in Current Biology. They tested 67 people in York, UK, at two different times of the year, January and June. Placed in a darkened room, the subjects were asked to adjust a colorimeter to display unique yellow, with no contamination from other colors. In general, the yellow selected during January tended to have more green in it than the yellow selected in June. The researchers say that’s because there’s more green naturally occurring in June than in January, so humans compensate by adjusting their perception of the other colors. The finding demonstrates one of the many ways that humans are able to constantly adapt to their surroundings, says Lauren Welbourne, the study’s lead author.