Some optical illusions give the impression of movement because of the way our brain interprets and analyzes visual information. Contrasts, lines, and patterns presented in these illusions can induce movements perceived by the brain, creating an illusion of motion.
Our brain manages reality by interpreting what our eyes see. Sometimes, it tries to make sense where there isn't really any, creating an apparent movement. This phenomenon occurs, in particular, when an image subtly suggests a movement without actually having one. Some illusions thus deceive the part of the brain responsible for interpreting movement, such as the V5 visual area. The brain is easily fooled, as it always seeks logic and coherence in what it perceives. As a result, you may have the strange sensation that a stationary image is moving before your eyes, while it remains perfectly still.
Certain specific associations of colors and repetitive patterns can easily mislead the brain. More specifically, when contrasting and repetitive patterns are placed side by side, they can sometimes disrupt our neurons responsible for visual processing. Our visual cells, sensitive to particular frequencies, start sending contradictory signals, and the brain struggles to interpret everything clearly. As a result, it sometimes creates an illusion of movement where there is none: the images seem to vibrate, oscillate, or even slightly rotate. This effect is particularly pronounced when the patterns use combinations of colors that strongly oppose each other, such as black and white contrasts, or very vivid tones placed side by side (like blue and orange). These strong contrasts increase the effect of neuronal confusion, making the illusion even more unsettling for our perception.
Our eyes, even when still, never remain completely fixed: they constantly move through tiny, rapid movements called micro-saccades. These minute shifts normally serve to prevent our vision from becoming blurry or from stabilizing too long on a single image. However, in the face of certain optical illusions, these micro-movements deceive our brain. As a result, it interprets these small involuntary shifts as actual movement of the drawing. Consequently, a perfectly still image appears to twist or ripple in place, even though it hasn't moved an inch.
Our eye functions like a somewhat slow camera: it retains for a very brief moment a light trace of the image it has just captured. This trace, called retinal persistence, lasts about a tenth of a second. As a result, when we quickly switch from one slightly different image to another, the brain merges these images and the impression of continuous movement appears. The same goes for certain optical illusions that play on small shifts: while our eyes move quickly from one part of the image to another, the residual images overlap with the current signal. Consequently, our brain is convinced it sees something moving, even though everything is perfectly still.
Did you know that the average human makes about 3 to 5 involuntary eye movements per second, known as microsaccades? These movements actively contribute to the creation of illusions by continuously stimulating visual receptors.
The persistence of vision is the basis of the functioning of many animated and cinematic films: it is thanks to this phenomenon that our brain merges a rapid succession of still images to perceive smooth motion.
Some optical illusions can induce a slight feeling of dizziness or visual discomfort because they disrupt the normal processes of the brain that are responsible for interpreting the stability of the surrounding world.
The illusion of movement can sometimes be stronger if you look at the image out of the corner of your eye rather than directly. This is due to the way our peripheral vision processes visual information, highlighting contrast and transitions more effectively.
Our eyes constantly make small vibrations called microsaccades. These subtly involuntary movements continually change the precise spot on which the eye focuses. In the case of illusions with repetitive or high-contrast patterns, these micro-movements disrupt brain visual processing and can thus create a sensation of movement.
Sure! Here’s the translation: "Yes. Static illusions are fixed images that nonetheless give the impression of movement due to visual tricks such as specific patterns or high contrasts. In contrast, animated illusions actually involve movement, but they lead to a misinterpretation of its nature or direction."
No, people perceive optical illusions differently depending on several factors: their age, their vision quality, their past experiences, or even their state of fatigue. Thus, some individuals may not see any movement where others clearly perceive a dynamic illusion.
Repetitive patterns create confusion in our brain's visual processing. It constantly seeks reference points to analyze what it sees. The repetition creates a perceptual ambiguity that gives the impression of a non-existent movement.
Generally, optical illusions are harmless. However, some people may experience dizziness, lightheadedness, or visual fatigue when exposed to these images for too long. If discomfort arises, it is recommended to look away or take a break.
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