Education
Scientists Trick the Eye Into Seeing a Never-Before-Seen Colour
Researchers at University of California, Berkeley have arguably expanded the frontiers of human perception by enabling participants to experience a colour no one has seen before. This hue, named “olo”, emerges not from a new pigment or natural light wavelength but from a radical experiment that stimulates the eye in a way nature never allows.
The human retina contains three types of cone photoreceptor cells—long-wavelength (L), medium-wavelength (M), and short-wavelength (S) cones—which together enable us to see the full gamut of colours in everyday life. Under natural lighting, these cones are activated in overlapping combinations, and our brains interpret their signals as distinct hues. The Berkeley team reasoned that if they could isolate the response of one cone type—specifically the M-cones—they might create a visual sensation that falls outside the usual colour space.
To achieve this, the scientists developed a system dubbed Oz, which uses adaptive-optics imaging, fine-grained eye-tracking and laser micro-pulses to map and then stimulate individual photoreceptor cells in a small patch of the retina. Once the map was established, they delivered pulses designed to activate only the M-cones, while minimising activation of the neighbouring L- and S-cones. The result: five participants (plus the experimenters) reported seeing a strikingly vivid blue-green that they described as unlike anything they had ever experienced.
The colour ol o is said to have an “unprecedented saturation” – far beyond what can be reproduced by conventional monitors or pigments. Because no natural light stimulus can activate M-cones entirely in isolation, the brain is processing a signal it never normally receives. The name “olo” derives from colour-space coordinates (0, 1, 0) in the LMS cone-activation framework, signifying only the M channel is active.
The implications of this experiment are intriguing. On one hand, it challenges the notion that the range of perceived colours is fixed and fully mapped; on the other, the technology behind the feat offers new avenues for exploring vision science. For example, the team believes the technique could help study colour-blindness, retinal diseases or even extended colour-vision (tetrachromacy) by directly manipulating which photoreceptors fire.
Yet there are caveats. Many vision scientists caution that calling olo a “new colour” may be semantic: it could simply be an extraordinarily saturated variant of blue-green rather than a wholly novel perceptual category. Moreover, the experience remains confined to a highly specialised laboratory setup—targeting a minute patch of retina, requiring the subject to keep very still, and using complex optical hardware. The researchers emphasise that this is foundational science, not something one will see on a smartphone or in everyday life anytime soon.
In short, by bypassing the natural blending of cone signals, the Berkeley team has revealed a glimpse of what lies beyond our everyday visual experience—a colour that exists in the realm of the possible, if not yet the accessible.
Read More : livescience.com/health/neuroscience/scientists-hijacked-the-human-eye-to-get-it-to-see-a-brand-new-color-its-called-olo?utm_source
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