VIDEO: ‘time-travelling’ illusion tricks the brain

Experimental psychologists have created a mind-blowing illusion that shows how human senses can influence one another and play tricks on the brain.

Researchers at the California Institute of Technology say their video illustrates “postdiction” (as opposed to prediction), a phenomenon in which a stimulus can change our perception of an earlier event.

They claim their work is “among the first to show this kind of time-travelling illusion across multiple senses”.

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In the video, dubbed The Rabbit Illusion, a flash and a beep occur almost simultaneously, followed by a beep and then another flash and a beep.

As the audio and visual stimuli occur rapidly, the brain blends the information from both senses in a bid to make sense of it, using postdiction.

As a result, although there are just two flashes, most people perceive three, because there were three beeps.

A second illusion, called the Invisible Rabbit, shows three flashes but only two beeps, leading the viewer to perceive only two flashes, since there was no corresponding sound with the third.

Noelle Stiles, author of a report on the research published in journal Plos One, says: “Illusions are a really interesting window into the brain. By investigating illusions, we can study the brain’s decision-making process. For example, how does the brain determine reality with information from multiple senses that is at times noisy and conflicting?

“The brain uses assumptions about the environment to solve this problem. When these assumptions happen to be wrong, illusions can occur as the brain tries to make the best sense of a confusing situation. We can use these illusions to unveil the underlying inferences that the brain makes.”