When eyes execute a saccade, perception of time stretches slightly backward. The viewer's brain registers that they have been looking at the clock for slightly longer than they really have, producing the illusion that the second-hand is frozen for more than a second. Although this happens every time the eyes move from one fixation point to the next, it is rarely noticed. One explanation is that the brain is filling in the gap while the eyes move from looking at one thing to the next.
chronostasis time perception brain consciousness