Our mind can move through time in any direction. It can choose its speed. It visits the future and revisits the past, whenever it wishes. We can compress or stretch time. Brain tends to condense time. Time seems to slow down when there is not much work and race when there is enough challenging work. An emotional event becomes more recent than it actually is. The brain also stretches the interval that has passed when the perception of time does not persist. Time flies when you’re having fun. The perception of time can heighten enjoyment and ease annoyance.

The time-perception experiment conducted by physiologist Hudson Hoagland in the early 1930s was based on an everyday observation. His wife had the flu. She made a usual complaint that her husband is away from her bedside for too long, even if he had gone away only for a short while. Isn’t it amazing that a common complaint could give birth to such an important time-perception experiment. Hoagland proposed to his wife quite an annoying experiment: Count off 60 seconds while he timed her with his watch. The result of the experiment: When her minute was up, his clock showed 37 seconds. In subsequent experiments he showed that his wife’s mental clock ran faster, higher her temperature became.

David Eagleman says, our illusions and distortions of time are consequences of the way our brain builds a representation of time. Our brain processes different types of sensory information at different speeds by different neural architectures. The difficulty our brain faces is that it receives signals from different modalities at different speeds in different neural regions. These signals must become aligned in time and correctly tagged to outside events. Eagleman says that the time slows down during brief, dangerous events such as car accidents and robberies. To understand why time slows down when we fear for our lives, Eagleman devised an experiment in a controlled setting. He designed a “perceptual chronometer”, strapped it to a subject’s wrist, where it would flash a number at a rate just beyond the threshold of perception. If time slowed down, Eagleman reasoned, the number would become visible. He found a young couple who volunteered to become his ‘material’ for the experiment on a suspended catch air device; a device to induce fear. In a dire situation, our brain may lay down memories in a way that makes them "stick" better. Upon replay, higher density of data would make the event appear to last longer. This may be why, reasoned Eagleman, time seems to speed up as you age: You develop more compressed representations of events, and memories are correspondingly impoverished.