How the brain tracks motion
As amazing as the human brain is, it does have some limitations, one of which is that it takes one-tenth of a second to process visual information. This would be especially problematic when trying to perceive an object in motion, particularly one moving very quickly. But scientists at the University of California, Berkeley found that the brain compensates for the delay by predicting the path of a moving object so that it can ‘see’ the object and respond to it accordingly.
One fundamental problem with the brain, the researchers noted, is that it does not work exactly in real-time; in fact, it actually functions more slowly than computers. So, by the time the brain is able to fully process information, the information is slightly dated. This is especially true when it comes to perceiving fast-moving objects.
To compensate for this lag, the brain is able to predict the intended path of a moving object, so the object that the eye ‘sees’ is actually the brain’s prediction of where that object will be one-tenth of a second from the moment you see it.
The researchers studied the brains of six volunteers using functional magnetic resonance imaging (fMRI), which indirectly measures brain activity by measuring changes in the blood flow in the brain.
The volunteers' brains were scanned as they watched an illusion called the "flash-drag effect," in which brief flashes of light shift over a moving background. The brain interprets the flash as part of the moving background, and therefore engages the prediction mechanism to shift the position of the flash.