Remember winter, when everything was cold and grey? Right now, when all around is lush and green, the contrast couldn’t be greater. But is everything really as it seems? New research shows that we see things differently in winter compared with summer.
Our eyes perceive four pure, unmixed colours – blue, green, red and yellow. People often find it hard to agree exactly what shade pure blue, green and red are, but curiously we tend to see pure yellow the same way, despite having different eyes. Lauren Welbourne, a psychologist at the University of York, wondered if that was because yellow is influenced more by the world around us than the biology of our eyes.
To test this idea, she invited volunteers to identify the shade they believed to be pure yellow in both January and June. She found that people consistently added more green to make “pure” yellow in June.
“In York, you typically have grey, dull winters, and then in summer you have greenery everywhere,” says Welbourne. “Our vision compensates for those changes, and that, surprisingly, changes what we think yellow looks like. It’s a bit like changing the colour balance on your TV.” Welbourne’s findings are published in Current Biology.
Most likely this process takes a period of weeks, so our eyes don’t retune for a cloudy day. And in some regions where there is less seasonal change – in rainforest, say – people’s yellow perception will barely change. “Clearly it is an adaptation to changing seasonal environments, but we are not yet sure why this is useful,” says Welbourne.
