in Head TripPopSci explores the connection between our brains, our senses, and the strange happenings that happen in between.
Imagine this: you are sitting somewhere. It is dark, so you don’t know where. But suddenly, you see three flashes of light, one after the other, very quickly. The flashes appear along a straight line, with a short gap between each one. The first flash is to your left, the second in front of you, and the third to your right.
But wait, did Do you understand? If you Visual jump illusionThe second flash actually occurred in the exact same place as the first one – it didn’t occur in the center of your field of vision, your brain just expected it to be there. should There was a flash there, so that’s what you saw.
This illusion is also known as the visual rabbit illusion, which is closely related to Skin jump illusionInstead of seeing a flash of light, participants received a quick tap on the arm. The second tap felt like it occurred between the first and third taps, something that earlier papers on the illusion said wasn’t the case. The researchers likened the sensation to a rabbit “hopping” along their arm. (Another version states that Similar auditory effects.
One common theme in illusions is that many of them seem to emerge when there is a mismatch between the information the brain expects from the senses and the information it actually receives. For example, the illusion of a stopped clock is induced by a situation in which the second hand of a clock is moving while your eyes are moving, so you don’t actually see any movement. The brain then steps in to “fill” the perceptual gap based on a prediction of when the movement will occur, but that prediction may be wrong.
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In the stopped-clock illusion, there’s a clear lack of information: Your eyes move as the clock ticks, so you miss the moment when the movement actually occurs. Is something similar happening with the visual leap illusion? Yes and no, says Cheryl Ann Manaligodo de Jesus, a doctoral student at Kyushu University’s Graduate School of Design and lead author of the paper. New paper on the visual vault illusion Released on May 21st i-Perception.
In this 2024 image, researchers from Kyushu University further explored the visual rabbit illusion: the three rabbits represent actual flashes of light, and the dots above them show where people perceive the light spot. The second dot is usually perceived near the center.
“in [this illusion]”Subjects ‘see’ all three flashes, but [they] You misperceive the location of the second flash.” How does this misperception happen? De Jesus explains that “your brain misinterprets the information it receives into the pattern that makes the most sense to you.”
why But why the brain does this remains relatively mysterious. A new study led by Dr. De Jesus and his colleagues at Kyushu University aims to investigate the subtleties of the illusion further. The team made slight changes to their experimental setup to see if these changes affected subjects’ perception of the illusion. The team’s results suggest that the brain’s desire to place the second flash between the first and third flashes – in the “most meaningful” location – is surprisingly strong.
In a traditional experiment, the second flash occurs in the same location as the first flash. The first change the team made to their experiment was to move the second flash to the same location as the third flash, a setup they call an “inverted” configuration. The second change increased the number of locations where the second flash could occur. In some cases, the second flash was placed outside the space between the first and third flashes. The purpose of these two changes, de Jesus explains, was “to test the strength of the illusion… Would ‘crossing the boundary’ produce the same effect?”
In both cases, the answer appears to be yes. Even when the second flash was outside the space bounded by the first and third flashes, participants still perceived it as being in the center of the space. With the third correction, the second flash was no longer linearly aligned with the first and third flashes. Again, participants perceived the second flash as halfway between the first and third flashes.
There are two main hypotheses to explain this illusion. One is that the brain’s tendency to mislocalize the second flash is based on a so-called “motion-based position shift”. The other is that it is due to “perceptual grouping”. As de Jesus explains, the first describes the phenomenon where “the position of an object or stimulus is influenced by the motion of the background”. In this case, participants “perceive the target object as shifting in the direction of the motion”.
According to this explanation, the continuity of the flashes creates the sense that they are a single object moving across participants’ field of vision. New research, particularly the reverse composition, seems to cast doubt on this idea. [it] “If this were true, the second flash would have been perceived as occurring after the location of the third flash, which may have also been misidentified,” De Jesus believes.
Perceptual grouping, on the other hand, is a more philosophical explanation based on Gestalt psychology and the idea that “the sum of the parts equals the whole,” which allows us to “see faces in a particular work of art, rather than a collection of random dots or brushstrokes,” de Jesus explains. (Another example would be the shape of a caniza.)
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De Jesus explains that this idea solves the mystery of the optical jump illusion by saying that while the eye sees three flashes as separate events, the brain interprets the visual information as three parts of a line. In other words, in De Jesus’ words, the brain interprets the visual data in the way that it thinks is “most appropriate.”
This 2018 video from a paper by a team at the California Institute of Technology shows a phenomenon similar to the visual leap effect: in this case, the perception of a second flash between the first and third flashes is caused by an accompanying beep, but in both cases the illusion arises from the brain expecting the second flash to occur in the “most meaningful” place.‘ To the brain.
Either way, de Jesus cautions that the answer to the question of why the brain errs in this case isn’t as simple as one or the other: “We can’t discredit one side or the other based on the overall results.” [theory] Or maybe not. Instead, she says, more research is needed.[Using] “Other devices measuring brain and eye activity would be interesting,” she says, as would investigating multiple simultaneous vaulting illusions. “It would also be interesting to combine sound and touch, or both, to test the same parameters.”
There are also intriguing hints at connections to other similar illusions. Kappa EffectFor example, a similar setup to the visual jump illusion would involve moving flashes through time instead of space. “There’s definitely a connection,” agrees de Jesus, “but it’s hard to say for sure what it is.” [it is]. both [illusions] These may result from motor signals and cognitive preconditioning, perhaps linked to the same neural mechanisms that manifest as different effects.”