BBC reports on an odd optical experiment that resulted in human eyes seeing an entirely new color, a kind of super-saturated aqua they’ve dubbed “olo”:
By stimulating specific cells in the retina, the participants claim to have witnessed a blue-green colour that scientists have called “olo”, but some experts have said the existence of a new colour is “open to argument”.
The findings, published in the journal Science Advances on Friday, have been described by the study’s co-author, Prof Ren Ng from the University of California, as “remarkable”.
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During the team’s experiment, researchers shone a laser beam into the pupil of one eye of each participant.
There were five participants in the study – four male and one female – who all had normal colour vision. Three of the participants – including Prof Ng – were co-authors of the research paper.
According to the research paper, the participants looked into a device called Oz which consists of mirrors, lasers and optical devices. The equipment was designed previously by some of the involved researchers – a team of scientists from UC Berkeley and the University of Washington, and updated for use in this study.
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There are three types of cone cells in the eye – S, L and M – and each one is sensitive to different wavelengths of blue, red and green respectively.
According to the research paper, in normal vision, “any light that stimulates an M cone cell must also stimulate its neighbouring L and/or S cones”, because its function overlaps with them.
However, in the study, the laser only stimulated M cones, “which in principle would send a colour signal to the brain that never occurs in natural vision”, the paper said.
This means the colour olo could not be seen by a person’s naked eye in the real world without the help of specific stimulation.
To verify the colour observed during the experiment, each participant adjusted a controllable colour dial until it matched olo.
Some experts, however, say the new perceived colour is a “matter of interpretation”.