A black hole seems to be expanding: but only a trick of our mind that tells the pupils to widen because it thinks we are entering a tunnel
Many people if they get closer looking at a dark region, a sort of black hole, they have the impression that it is expanding rapidly. and’optical illusion, actually the dark area remains stationary on the paper (or computer screen) and is not moving or increasing its surface. Researchers now believe that the image plays a trick to our brain, which it thinks of moving towards a dark tunnel or cave. L’optical illusion works particularly well if the dark area has an elliptical shape ed surrounded by a dark halo on a white background filled with small black ellipses. When you start looking at the image, the dark elliptical area appears for a couple of seconds expand outside. The researchers found that 86% of the 50 men and women who participated in the experiment had seen the expanding dark ellipse. According to the scientists, who published the study in Frontiers in Human Neuroscience, theoptical illusion explains how the brain perceives light level changes.
The brain and the pupil
The expanding hole is an illusion that possesses great dynamism, explains Bruno Laeng, a psychologist at the University of Oslo who led the study. He makes the brain believe that there is a change in brightness as if we are approaching the entrance to a tunnel, which is not actually there. He sidetracks a natural reaction of the brain, which predicts when the brightness is about to change. When this happens, the brain triggers the contraction or dilation of the pupils of the eyes to prepare in advance for the light variation. The researchers used a special equipment to observe the eye movements of the subjects analyzed, finding the relationship between dilation of the pupils and the sensation of expansion of the dark figure that their brains perceived. Those who saw the dark area expand the most were those who had the greatest eye dilations.
Light and reality
It shows us that the pupils react to how we perceive light, even if the imaginary light does not correspond to reality, adds Laeng. If the background colors and the elliptical area were white instead of black, the opposite reaction occurred: the pupils contracted instead of expanding. It remains for a question that researchers have not yet been able to answer: why some people fail to see the expansion of the dark area. The optical illusion doesn’t work on them. Similar animal tests will now be carried out to solve the mystery.
June 13, 2022 (change June 13, 2022 | 12:33)
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