Five people just saw a color no one had ever seen before. Here’s how.
In the back of your eye are special cells that let us see color - cones. There are three kinds, each sensitive to different wavelengths of light. So if you make a map of the relative activity of each of the cone types, you can see the natural range of colors our eyes see.
Weirdly, there’s no natural color that stimulates only one of the types of cones - because its sensitivity curve overlaps completely with the others, so another cone type is always also activated.
Scientists at UC Berkeley just created a device that images where the cone cells in a person’s retina are and then stimulates individual ones using tiny amounts of laser light while compensating for any motion. They were able to stimulate JUST the M cone cells.
