This Optical Illusion Has Left 86% of People Baffled


| LAST UPDATE 06/06/2022

By Stanley Wickens
optical illusion black hole
Os Tartarouchos via Getty Images

Optical illusions play tricks on our brains in so many ways, whether they are physiological, cognitive, or literal. New research on the latest image to fool our eyes says most people look at it and see the image of an expanding black hole...

Although the picture is completely static, researchers say that the impression it gives people is "a growing sense of darkness, as if entering a space voided of light." But according to a new study, there's a scientific explanation for it all: preparing our eyes to transition from light to darkness. "Just as glare can dazzle, being plunged into darkness is likely risky when navigating into the darkened environment," the researchers wrote in their paper. In other words, the expanding effect of the 'black hole' in the image is just our eyes preparing themselves for a metaphorical light to be switched off.

optical illusion black hole
Instagram via @theoptometry
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In nature, it's all about finding a balance. "Although, as in any illusion, this virtual expanding darkness is experienced at the cost of veridicality, since the observer is neither moving forward nor entering any dark space, such a cost is likely to be less severe than if there were no corrections when an observer really moved forward into a dark space." To dive further into how the image affects our mental and physiological responses, a study was conducted on 50 participants. They were each presented with the image of the 'expanding hole' in various colors on a screen, and their eye movements were tracked throughout the study. Researchers concluded that the participants' pupils were continuously dilating when the hole was black and only slightly contracted at the sight of the white hole.

Researchers were fascinated by the results of the study. "Here, we show based on the new 'expanding hole' illusion that the pupil reacts to how we perceive light – even if this 'light' is imaginary like in the illusion – and not just to the amount of light energy that actually enters the eye," explained psychologist Bruno Laeng from the University of Oslo in Norway. "The illusion of the expanding hole prompts a corresponding dilation of the pupil, as it would happen if darkness really increased." The researchers now plan to test the illusion on animals to better understand the evolution of the human visual system. Could this optical illusion unlock new insights into how human brains process visual information? We'll be staying tuned to find out.

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