Felt Time

Before the invention of clocks, how did humans gauge time? After all, clocks have only existed for a tiny fraction of human evolution’s long history.

Luckily, we have psychological mechanisms that help us keep track of time.

Oxford psychologist Michel Treisman put forward the pioneering idea of a psychological clock in the 1960s. According to Treisman, our brains have a pacemaker that emits pulses at regular intervals, and the pulses are collected by a counter in our minds. Our brains then determine the passage of time by the number of pulses the counter detects.

Treisman argued that the counter registers time pulses only when we’re paying attention to the time – for instance, when we’re waiting for something. When we’re distracted and not thinking about the time, on the other hand, fewer pulses are counted, making time seem to pass more quickly.

A more recent scientific theory of our psychological clock posits that we can estimate the temporal duration of events by gauging the amount of intellectual and emotional exertion they require.

Consider how new experiences often feel like they last longer because they demand greater faculties of perception, thought and emotion.

And guess what? We’ve been blessed with not just a psychological clock, but also a physiological one, known as our circadian rhythm.

The circadian rhythm is a biological process of changes that happen to our bodies in response to daily light cycles. Cognitive performance is one of the things affected by our circadian rhythm – for example, many cognitive operations hit their peak before noon and slow down as the day progresses.

Fascinatingly, our bodies follow circadian rhythms even if the sun isn’t visible.

In the 1960s, psychologist Jurgen Aschoff conducted a set of experiments in which volunteers were kept in a room with no natural light. Despite being shut out from the outside world, Aschoff found that the volunteers’ sleep schedule and body temperature still followed a circadian rhythm.