Read more: “About time: Adventures in the fourth dimension“
CAN you count off 5 seconds in your head? Chances are that if you did, and then checked your estimate with a stopwatch, you would be pretty close. But have you ever stopped and wondered how your brain achieves this amazing feat?
Time perception is one of the enduring mysteries of the brain. While we have a fairly good grasp on the millisecond timing involved in fine motor tasks and the circadian rhythms of the 24-hour cycle (see “The body’s metronome”), how we consciously perceive the passage of seconds and minutes – so-called interval timing – remains decidedly murky.
For a start, there is no dedicated sensory organ for time perception, as there are for perceiving the physical and chemical nature of our environment through touch, taste and smell. Time is also unusual in that there is no clinical condition that can be defined purely as a lack of time perception, which makes it difficult to study. “What we really want is someone who is as bad at timing as amnesiacs are at memory,” says John Wearden of Keele University in the UK. “But there are no such people.”
Some believe there’s a reason for this. Warren Meck of Duke University in Durham, North Carolina, thinks timing is so fundamental to cognition that our brains have developed several back-up systems that can kick in if the main clock is damaged, which is why it is so difficult to find anyone who cannot perceive time.
As for what the biological basis of such clocks might be, nobody really knows. The closest anyone has got ...