Scientists in California have developed an illusion that will make you see something that isn't really there
Pasadena, California – October 12, 2018
Everyone in the world imagines that they are living in the present, but, in a certain sense, they are not. Before making its way into your consciousness, the content of your sensory perception travels quite a long way from the sensory receptors to your brain.
Scientists at the California Institute of Technology (Caltech) are using this video to explain a bizarre phenomenon in the brain.
It shows a series of beeps and flashes in quick succession. You have to stare at a cross in the middle of the screen and watch to see how many flashes appear along the bottom.
Most people will see three flashes, the same as the number of beeps, but when the video is viewed without the beeps, only two flashes are seen.
This is because our brains play a trick on us to fill in the gaps in our memories. The beeps trick your brain into thinking there are three flashes.
The illusion is referred to by scientists as the “Illusory Rabbit.”
A Caltech spokesperson said, “Though only two flashes are played, most people viewing the illusion perceive three flashes, with an illusory flash coinciding with the second beep and appearing to be located in the center of the screen.”
This phenomenon in the human brain is called 'postdictive processing'.
Noelle Stiles, lead author of the study told Caltech: "When the final beep-flash pair is later presented, the brain assumes that it must have missed the flash associated with the unpaired beep and quite literally makes up the fact that there must have been a second flash that it missed.
In reality there are only two flashes but your brain fills in the gaps
"This already implies a postdictive mechanism at work."
She added: "But even more importantly, the only way that you could perceive the illusory flash would be if the information that comes later in time—the final beep-flash combination—is being used to reconstruct the most likely location of the illusory flash as well."
This study explains how postdiction contributes to how our brains combine different senses to interpret our environment.
The reason for these illusions is so our brains can make sense of past events, often filling in the gaps we may not have actually seen.deo arrow ALWAYS point right
Ms Stiles continued: "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."
Shinsuke Shimojo, a researcher in the study, explained: "Postdiction may sound mysterious, but it is not—one must consider how long it takes the brain to process earlier visual stimuli, during which time subsequent stimuli from a different sense can affect or modulate the first.
"These illusions are among the very rare cases where sound affects vision, not vice versa, indicating dynamic aspects of neural processing that occur across space and time."
If we consider this trick just as a sort of some fun we could put an end with this subject. However, Caltech is not an ordinary scientific center, as to important secret projects, it competes only with the Massachusetts Institute of Technology.
In particular, in the same 1950s with the Massachusetts Institute of Technology was involved in studies of the subliminal message, better known as the "25th frame effect". And only now, half a century later, Caltech reveals the secret of another “miracle technology” of the TV impact on brain. Now we even cannot imagine how many tricks they have in their bag.