What colour are the dots in this optical illusion?

"'In this paper a novel optical illusion is described in which purple structures (dots) are perceived as purple at the point of fixation, while the surrounding structures (dots) of the same purple colour are perceived toward a blue hue.'"

"'As the viewing distance increases, a greater number of purple structures (dots) revert to a purple appearance.'"

"'We don't notice this usually,' Jenny Bosten, a visual neuroscientist at the University of Sussex, told Scientific American. '[That's] because our brains have learned to "calibrate" out the difference.'"

A new optical illusion reveals how our perception of color can be distorted. Created by Hinnerk Schulz-Hildebrandt, the illusion shows that dots appear purple at fixation but shift to blue when viewed peripherally. The study highlights the role of color-detecting cells in our eyes, specifically L-cones, S-cones, and M-cones, which respond to different wavelengths. S-cones, responsible for detecting blue, are sparse in the area of sharpest vision, leading to misperceptions of color, particularly blue, which our brains often calibrate out.

Read at Mail Online