Cognitive Science: An Introduction/Time Psychology

Time Perception is Ancient

Like animals, plants and even some single-celled organisms also have a circadian clock, which keeps track in time by monitoring blue light. Most single-celled organisms, including bacteria and fungi, use a circadian clock to replicate at night, presumably to protect themselves from the damage of ultraviolet radiation. Keeping track of time evolved very long ago, making the perception of time one of the most evolutionarily ancient parts of minds.

The Clocks in our Brains

Our brain keeps track of time to know how much of it has passed. This is time perception, and the right prefrontal cortex seems to be important for it.

Rather than keeping track of time with a single clock in the head, the brain uses multiple ways to keep track of time, at different scales.

When you have people come into the lab and listen to clicks, people can differentiate between two with only a five-hundredth of a second between them.

Even understanding speech requires keeping track of time at the millisecond level. That is, there are some differences in meaning that depend on the length of time spent on particular sounds.

The part of your brain called the basal ganglia seems to be important for lengths of time greater than two seconds.

The circadian rhythm clock in our body keeps track of 24 hour periods, but this system has no sense time at the scale of hours, minutes, or seconds. The part of the hypothalamus gland called the suprachiasmatic nucleus has neural oscillations that keep track of 24 hour periods, adjusted by daylight. Without daylight, one study found that the time kept was 24 hours and 31 minutes. So over days this can get far off of normal days. The receptors used to detect light in service of the circadian system use the same chemical that plants do to do the same thing--a chemical called cryptochrome.

Even when we're asleep we're pretty good at knowing how much time has passed. One study found that we were accurate to within 15 minutes.

Why Time Speeds Up As We Age

When we look back on an event, one of the ways we judge how long it lasted is by looking at how many new memories were encoded. The more memories we encoded, the longer an amount of time it feels like. This is why the trip back seems shorter than the trip to a new place--on our way there, we are encoding lots of new landmarks, but on the way back we are mostly recognizing them. This is also why time seems to speed up when you grow older. As you experience life, you learn about more and more things. Think about how fascinated kids are with everything they see. As you grow older, you just recognize them. Dog, car accident, the color green. They are merely recognized, not encoded as new things. As a result, because fewer things surprise you, it feels like time is going faster.

A version of this theory, From David Eagleman, is the resource-allocation or time-sharing hypothesis. It's just more efficient to process things you recognize, and it's the consumption of energy that is associated with time passing.

Warping of Time

We estimate time in a few ways. If we start keeping track of time now, and try to guess when a certain amount of time has passed, we call it "prospective time estimation." If we look back on an event and try to estimate how long it took, it's called "retrospective time estimation."

If you're bored, you overestimate prospective time (you think time passes faster than it is--"it's only been 15 minutes?!"), but in retrospection it seems shorter. Time also seems to fly when we're busy--that is, it feels like it's moving slower than it really is, so we feel surprised when two hours have gone by. One theory of why this is states that we just have fewer mental resources to attend to time passing. When you're bored, you pay attention to the time, but when you're busy, you're simply thinking of other things.

Our sense of how much time has passed can be lengthened by extreme fear, boredom, rejection, depression, having a high temperature, and having Attention Deficit Hyperactivity Disorder (ADHD).

Metaphorical Views of Time

In the chapter on conceptual metaphor, we discussed how people use their understandings of concrete things in the real world to make sense of abstract things. This happens for time too.

Suppose there was a meeting on Wednesday, but it gets pushed forward two days. What day do you think it's on now, Friday or Monday?

It turns out that your answer to this question is indicative of how you are thinking about time. Some people feel that they are moving through time, as though time were some substance, like air or water, that they are moving through. Others see themselves as being relatively stationary, and time is flowing over them, like standing in the wind or in a river. People who see time as flowing around them are more likely to think that the meeting is on Monday. People who see themselves as actively moving through time are more likely to think it's on Friday.

People who are waiting tend to use the time-moving metaphor. People about to do something use the ego-moving metaphor.If you are looking forward to something, you are likely to use the ego-moving metaphor, and if you are dreading it, the time-moving one.

Sometimes we think of time in terms of space, and sometimes we think of it in terms of an amount. For example, we might say "a long time" (using the space metaphor) or we might say "a lot of time" (using the amount metaphor). In Greek, they refer to to time as a size--they might say something like "a big time."

Not only does our language reflect this, but experiments show that it really affects the way we think about time. People who spoke languages with different time metaphor were asked to estimate the amount of time something happened on a screen. That something was sometimes a line getting longer, and sometimes it was a container filling up with water. People's estimations of time could be influenced by what they were seeing if it corresponded with the metaphor their language used.

Mental Time Travel

Sometimes called chronosthesia, mental time travel is when we imagine the past or the future. We think about the future a lot. People think about the future, on average, 59 times per day. That’s once every 16 minutes.

When Things Are Done Matters

An analysis of internet search data found that people are most likely to ask the big questions, like the meaning of consciousness and the existence of free will, between two and four in the morning.

Cultural and Time

What seems like a long or short time can depend on our cultural expectations. For example, we expect a play to take about two hours, and if it takes longer we feel that it drags.

Does it feel as though things more faster in some places than in others? In 2006 A scientist named Robert Levine went to 31 countries and measured walking speed, time taken to buy a stamp, and the accuracy of clocks in banks. He found that the fastest countries were the USA, those in Northern Europe, and the South East Asian countries. There was even variation within countries. In the USA, for example, Boston was the fastest city, and Los Angeles was the slowest.

A tribe in the Amazon basin, called the Amondawa, have no words for time, month, or year. They have no clocks and no calendar. They can conceive of sequences of events, but just not time.

In contrast, the word "time" is used more than any other noun in English.