Keeping track of time can play tricks on your mind.

While time might stand alone as a separate, empirical dimension, the way humans move within and perceive time is not as simple as the ticking of a clock.

Unlike the other senses — touch, taste, vision, hearing, smell — our sense of time is not associated with a specific, localised region in the brain. Instead, our sense of time overlaps our awareness of the world in many different ways, so a distributed system of brain regions is responsible for keeping track. It’s not easy. Different types of information are processed at different speeds, so to create a comprehensive, sensible view of the external world our brains must somehow compile all these different inputs into one.

Associate Professor Derek Arnold from the University of Queensland’s School of Psychology Perception Lab says increased concentrations of a brain chemical called dopamine seems to make time pass rapidly, while decreased levels made time seem to pass by more slowly.

“In essence, anything that makes you feel good — or bad — will have modulated dopamine levels in your brain, and this can have an impact on your impression of time,” he says. It appears time really does fly when you’re having fun.

High-stress scenarios

People often recall time ‘slowing down’ in life-threatening situations, but were they actually reacting faster to stimuli or did it just feel that way?

Dr Arnold says studies on this topic have so far proved inconclusive. “There is an almost unbreakable ambiguity as to whether you have distorted your perception of time … or whether you simply have a distorted recollection of time,” he says. “Of course from a pragmatic
perspective it doesn’t really matter — to you, time seems to have flown, because that is how you remember it. The reality of how things may or may not have seemed at the time won’t change your recollection.”

Temporal Illusions

There are several different events, called temporal illusions, which can cause a distortion in the perception of time.

• “Feels like it was only yesterday…” – The telescoping effect means people will tend to recall recent events as happening further back in time than they actually did, and distant events as occurring more recently. There are several theories as to why this happens, including the suggestion that people use a measure of detail to infer how long ago an event occurred—this means memorable events are recalled as happening more recently.

• Chronostasis – Ever looked at the second hand on an analogue clock and noticed that it appears to have stopped, or is moving slower than usual? This is due to an overestimation of temporal duration following a quick eye movement caused by your brain predicting events prior to perception.

• The odd-ball effect – This illusion further highlights the relationship between predictability and time perception. “If you see a sequence of flashed images that are all the same and flashed for equal periods of time, inserting an unexpected odd-ball — say a picture of a cow amongst repeated images of a chicken—the unexpected image seems to persist for a much longer duration,” says Dr Arnold.

• Wired on caffeine – It’s not just your brain playing tricks on you. There are many outside influences that can affect your perception of time, like drugs and alcohol. Stimulants such as caffeine and nicotine activate dopamine receptors in the brain, speeding up time perception, while depressants such as alcohol have the opposite effect and will make you feel that time is passing by slowly.

What’s your perception of time? Let us know in the comments below.