How good is YOUR colour perception? Deceptively difficult test tasks you with finding the boundary between two shades – so, how far can you get?
How accurate is your color sense? A challenging test reveals your visual limits
A newly launched assessment is designed to push your understanding of color perception to its edge, testing whether you can discern subtle differences in hues. As the difficulty increases, the task becomes progressively more intricate, demanding sharper focus and attention to detail.
Gameplay mechanics and progression
The ‘What’s My JND?’ game displays two color blocks and prompts you to click the dividing line between them. While this seems straightforward at first, the challenge intensifies as the colors grow increasingly similar. The instructions emphasize that “it starts simple, but doesn’t stay that way,” highlighting the evolving complexity.
Participants are given approximately 40 rounds to complete the test. The average score, representing the smallest detectable color shift, typically hovers around 0.02. Each round requires identifying the boundary, with feedback provided after every attempt to guide your progress.
Design and developer insights
Conceived by software engineer Keith Cirkel, the test aims to explore the precision of color differentiation on digital screens. The concept stems from a curiosity about how accurately humans can perceive color variations. To begin, navigate to the game’s website and click the “Let’s go” button.
As the game advances, the color pairs become harder to distinguish. Early stages feature contrasting hues like grey-blue or brown-orange, but later rounds introduce nearly identical shades, testing your ability to spot the faintest differences. A final score is calculated, comparing your performance to others who have played.
Player experiences and reactions
Feedback from users suggests the game is both engaging and revealing. One participant noted, “This is great fun. How good is your color perception? What are the finest shades you can distinguish? Apparently I’m a bit special,” sharing their surprise at the results. Another added, “Some were just completely uniform to me. I had no idea. Had to keep tilting my screen all ways to try to spot a border but still ended up guessing.”
“Not bad considering I’m colourblind.”
Some players even humorously question their own abilities, with one message stating, “Rough. But look, I once failed a colour vision test because the room had fluorescent lighting. Environment matters. Try again in a dark room with your brightness cranked. Or don’t. I’m not your mum.”
Color vision: The science behind the test
Color perception relies on specialized structures in the eye. The pupil adjusts to control light intake, much like a camera lens. Most species, including humans, possess cones and rods—photoreceptors in the retina that serve distinct functions.
Cones are responsible for color detection, while rods excel in low-light conditions, enabling a grey-scale vision of black and white. Humans and several other animals have three types of cones, each sensitive to different light wavelengths. This trio allows for the full visible spectrum, ranging from red (around 700 nm) to blue (approximately 390 nm).
Interestingly, certain species, such as many birds, have four cones due to a trait called tetrachromacy. This adaptation enables them to perceive ultraviolet light, expanding their color spectrum beyond what humans can detect. When light interacts with these photoreceptors, it generates electrical signals that travel through the optic nerve to the brain.
The brain then processes these signals at the optic chiasm, where it compares the input from both eyes to form a cohesive visual image. This intricate process underscores how color differentiation is both a biological and cognitive feat.
Advanced challenge: Hard Mode
For those who succeed in the initial test, Hard Mode offers an even greater challenge. In this version, nine color squares are presented, with eight sharing the same hue and one being distinct. Your task is to identify the odd square, requiring heightened awareness and precision.
By engaging with this test, participants not only assess their own color perception but also gain insight into the broader biological mechanisms that enable vision across species.
