BBC – Radio 4 – Frontiers 17/05/2006
When time seems to fly or drag, it’s nothing to do with our internal clock speeding up or slowing down. It’s how the brain processes time-related information that generates the illusion.

When a person’s life is in danger, a phenomenon known as ‘time-dilation’ can occur. This is when, during a car crash for example, time seems to slow down or become frozen.

In these cases the body’s internal clock speeds up when facing a potential catastrophe, so that it can take in more information more quickly and function more effectively in an emergency.

This is also a phenomenon actively sought by elite sportspeople, when they get ‘in the zone’.

Some of the chemicals in the brain, such as dopamine, can affect our perception of time. Deficiencies in these chemicals can lead to brain disorders.