it takes anywhere from one-thirtieth to one-tenth of a second for a visual stimulus falling on the retina of the eye to evoke neural activity in the brain. This time is long enough for a rapidly moving object to cover a fair distance, implying that when we see such an object, it should appear to be some distance behind its actual location.

However, both everyday experience and careful experimental measurements indicate that this is not the case: humans are quite good at spotting where a moving body actually is. This suggests that there must be a mechanism that helps our brain use the information that something is moving at a certain rate to constantly extrapolate, or predict, where the body will be in the future. This means that what we