A Breakthrough in Color Perception
In a bold and controversial leap in vision science, researchers in the United States claim to have uncovered a new color olo never before experienced by the human eye. The color, dubbed “olo,” is described as a highly saturated blue-green hue that emerged during a unique experiment involving laser pulses aimed at individual cone cells in the retina. Published in Science Advances on April 18, the study explores how such targeted stimulation may extend the boundaries of human color perception.
The research team used laser technology to isolate and stimulate specific M-cones, the retinal cells responsible for detecting green wavelengths. By avoiding overlap with other cone types — a condition rarely possible with natural light — researchers generated a visual response unlike any participants had encountered before. “We predicted from the beginning that it would look like an unprecedented colour signal,” said Ren Ng, an electrical engineer at the University of California, Berkeley. “It was jaw-dropping. It’s incredibly saturated.”
Participants in the study, five in total, struggled to describe the color using traditional vocabulary. Although they referred to it as “blue-green,” they agreed the term fell short of capturing its unique appearance. Their descriptions were supplemented with dial-based color adjustments to visually approximate what they saw during the laser stimulation.
The Science Behind ‘Olo’
The retina’s ability to perceive color depends on three types of cone cells: S-cones for blue, M-cones for green, and L-cones for red. Typically, natural light activates a blend of these cones, making isolated stimulation — and by extension, completely new color experiences — nearly impossible. But the laser-based method developed by the research team defied this limitation by isolating only the M-cones, delivering a pure signal to the brain without interference from the others.
This highly controlled environment allowed the brain to process a visual cue outside of its normal operating parameters. Scientists believe this novel approach has led to the experience of a color not found on the typical spectrum. According to the study, this new color olo was consistent among all participants, though it defied precise categorization. The result challenges the long-held belief that human perception is bound by the traditional color triangle formed by red, green, and blue.
To record the experience of “olo,” each participant was asked to adjust a digital dial to reflect the color as accurately as possible. The data collected provides the first formal attempt to represent this elusive visual phenomenon.
A Divided Scientific Community
Despite the excitement surrounding the discovery, some scientists remain unconvinced. John Barbur, a vision expert at City, St George’s, University of London, has criticized the claim that new color olo. “It is not a new colour,” he argued. “It’s a more saturated green that can only be produced in a subject with a normal red-green chromatic mechanism when the only input comes from M cones.”
Barbur and others suggest that while the experience may be intense or unusual, it doesn’t break the boundaries of human color perception, but rather exploits a rare but explainable condition within it.
Nevertheless, the research has sparked a vibrant discussion on the malleability of human vision and the potential for undiscovered experiences still hidden within our sensory systems. Whether “olo” stands the test of scientific scrutiny or fades into the realm of perceptual illusion, its introduction has undeniably challenged conventional understanding of what the human eye can see.
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