Time perception

Time perception refers to the human mind’s ability to subjectively experience the passage of time and the duration of events. On an everyday level, time seems to be absolute. After all, humans measure time in predetermined intervals, such as one minute totaling sixty seconds, one hour totaling sixty minutes, and one day totaling twenty-four hours. However, when the human mind attempts to perceive the passage of time, people often experience the movement of time at seemingly different speeds. This phenomenon is illustrated by the common experience that time “flies” when a person is having fun, but “drags” when they are engaged in a boring activity. Modern researchers remain unsure exactly why people seem to experience time differently, but they believe time perception is influenced by several psychological, environmental, and neurological factors.

Background

Humans have attempted to understand the concept of time for thousands of years, with many cultures making a distinction between measurable, chronological time and the abstract, philosophical aspects of time. For example, the ancient Greeks thought of time in two ways. They used the term chronos to describe the sequential passage of time, and the word kairos to refer to an opportune moment in time to take action. Some Greek philosophers believed that the passage of time was merely an illusion perceived by humans, while others thought time moved in precise accordance with the motion of the heavenly bodies. The philosopher Aristotle believed that time was only a measurement of change. In his view, this change needed to be perceived by humans in order for time to truly exist.

Without the benefit of clocks, ancient peoples relied on the movement of the sun, moon, and stars to mark the passage of time. The idea of dividing time into units of sixty originated in Mesopotamia where both the Sumerians and Babylonians used a number system based on sixty, rather than the base-ten system used in modern times. The Egyptians are believed to be the first civilization to divide time into units of twelve. They counted the passage of time at night by the movement of twelve star patterns through the sky. Because they used sundials to count time during daylight, Egyptian days varied in length, with some being measured in units of ten. Eventually, the Egyptians standardized their timekeeping into a set of twelve daylight hours and a set of twelve nighttime hours. Over the course of many centuries, these units of time measurement evolved and became incorporated into modern standards for keeping track of time.

Overview

For much of human history, the concept of time perception was relegated to the realm of philosophy and debated on an abstract level. Many of the philosophers from the Enlightenment period of the seventeenth and eighteenth centuries had ideas about time that echoed the arguments from ancient Greece. For example, one view held that time exists as part of the fundamental structure of the universe and moves at an eternal pace no matter how humans divide or classify its movement. Another concept stated that time is made up of temporal “particles” that manifest themselves as duration and can only be perceived by the human consciousness. Once humans try to measure this duration, the particles are gone, making direct measurement impossible. As a result, people are only capable of measuring time indirectly, which makes its passage seem different to different people.

In the late nineteenth century, the founders of modern psychology began to examine time perception from a more scientific standpoint. Among the pioneers in the field were German psychologists Gustav Theodor Fechner and Ernst Heinrich Weber, who explored how the human senses experience the world around them. Both Fechner and Weber performed experiments to gauge how humans judged perceived time versus measured time. Through their work, and the work of many others, modern psychologists have determined that humans do not physically perceive the passage of time itself. Rather, people experience changes in events over a period of time. People are aware that events occur and can identify those events as happening either simultaneously or in succession and in order of sequence.

Scientists believe that there is a neurological process in the brain that affects time perception, but they have yet to discover the exact mechanism that allows it to work. It has long been known that humans possess a biological clock that corresponds with the circadian rhythms of daily life. This internal clock keeps the human metabolism in tune with the cycles of day and night, affecting sleep, waking, eating, and other body processes. The internal clock that governs time perception is separate from the circadian clock.

Time perception is believed to be distributed throughout different parts of the brain, rather than confined to one section or along one specific sensory pathway. Evidence suggests the cerebral cortex, cerebellum, and basal ganglia may have a role in time perception, but research is not conclusive. These three sections of the brain perform various functions, but all have some connection to attention, learning, and awareness. However, in experiments performed on laboratory rats, scientists have found some continued time perception in animals that have had the higher sections of their brain removed. This points to the possibility time perception may originate in a lower, more primal, section of the brain.

One of the ways the brain functions is through the production of neurotransmitters, substances that act as chemical messengers that send signals from one part of the brain to another. Two of these neurotransmitters—dopamine and norepinephrine—have been linked to time perception. Dopamine acts as the body’s reward system, producing feelings of pleasure or satisfaction in response to stimuli. Norepinephrine is similar to adrenaline in that it increases alertness and action in times of stress or danger. Though researchers are not sure of the reasons, they have found that dopamine seems to speed up time perception, while norepinephrine seems to slow it. This may explain why people engaged in fun or pleasurable activities often feel like time just rushes by. At the same time, it may also be why people involved in accidents often say time seemed to move in slow motion while the traumatic event was occurring.

Scientists theorize that this effect may be an evolutionary trait developed by the ancestors of early humans. Under extremely stressful situations, such as when faced with a predator, the perception that time is slowed down may have allowed our ancestors what seemed like more time to process information. This may have given them just enough perceived extra time to make a decision to run or fight, and thus increased their chances of survival.

When people are specifically asked to estimate the passage of time, scientists have found that nerve cells from the base of the brain become active and begin producing chemicals. These chemicals then trigger a response in the prefrontal cortex, which covers the frontal lobe in the cerebral cortex. This section of the brain is one of the last sections to mature in childhood, which may explain why infants and young children have very little concept of the passage of time. In many cases, when people consciously try to gauge how much time has elapsed without the help of a clock, they seem to underestimate the true passage of time. For example, test subjects kept in sensory isolation routinely come up short when estimating how many days have passed since the experiment began.

Time and Age

The way the brain processes information is also believed to have an effect on time perception. When the brain receives raw information from the senses, it does not process that information in the correct order. The brain needs time to reorganize that information in such a way that it can be interpreted and understood. As would be expected, the brain takes longer to recognize new information and less time to process familiar information. Because the information from new experiences requires extra processing time, those moments can seem to last longer, while familiar experiences seem shorter. This may be the reason why the three months of summer vacation seem to last longer to a child, but go by faster for adults who have experienced many summer days in their lives.

This effect may be one of several reasons that time seems to move much slower for younger people and seems to pass by more quickly as people age. After all, to a two-year-old, almost everything in the world is a new experience; a twenty-year-old has likely gone to the same places and practiced the same daily routine for a number of years. Another factor in how people experience time as they age is that younger people have had less life experience to use as a baseline to gauge the passage of time. For example, a year may seem longer to a ten-year-old because they have only experienced ten of them. A forty-year-old has experienced four ten-year periods, so a year makes up a much smaller percentage of the total lifespan. Researchers also believe that the biological processes of aging that slow down a person’s metabolism may actually speed up their perception of time. A slower metabolism may cause older people to underestimate the passage of time, making it seem like time is moving faster. Researchers have noted that larger animals with slower metabolisms do seem to experience time more quickly.

Experiences and Emotions

Psychologists believe the way the brain processes information is responsible for a phenomenon known as the oddball effect. This occurs when the brain experiences something out of the ordinary and needs more time to process the information it is receiving. In experiments, scientists have found that when subjects are presented with a series of images, with one image being something unusual or different from the rest, the test subjects perceive the “oddball” image to have stayed on the screen longer.

Researchers have also noted several physiological “illusions” that seem to affect the perception of time, speeding it, slowing it, or even making it appear to stop. One of those is called the kappa effect, which involves the perceived time between a sequence of stimuli. Experiments done with a flashing sequence of three lights show that people perceive the duration between successive lights—the first and second or second and third—to be shorter. This is despite the fact the lights flash at regular intervals. Another illusion, known as chronostasis, or the stopped-clock effect, can occur in the split second after the brain is presented with a new event or stimuli. In this instance, a person perceives time to stop for a brief moment. This can be demonstrated by looking at the seconds hand of a non-digital clock. If a person watches the clock for an extended period of time, the hand would seem to move at a steady pace. However, if the person were to turn away and then look back at the hand, it would appear to “freeze” in place upon first glance.

Human perception of time can also be impacted by the environment and the emotions caused by the world around us. For example, people who spend a busy day working at their job may perceive time as moving faster. If they have to spend their day in the waiting room of a doctor’s office, they may feel the time dragging on longer. Psychologists have also found that people who work or live in an urban environment, experience time as moving faster than people in a rural setting. People who experience awe-inspiring natural wonders such as waterfalls or scenic vistas also perceive time as moving slower. These environmental effects have also been observed when people are shown images of city scenes compared to images of nature. Though the pictures are shown for the same amount of time, test subjects routinely claim that the nature images are displayed for a longer duration.

Bibliography

Allman, Melissa J., and Warren H. Meck. “Pathophysiological Distortions in Time Perception and Timed Performance.” Brain,vol. 135, no. 3, March 2012, academic.oup.com/brain/article/135/3/656/263693. Accessed 12 Jan. 2025.

Carey, Benedict. “Where Did the Time Go? Do Not Ask the Brain.” New York Times, 4 Jan. 2010, www.nytimes.com/2010/01/05/health/05mind.html. Accessed 12 Jan. 2025.

Dawson, Joe, and Scott Sleek. “The Fluidity of Time: Scientists Uncover How Emotions Alter Time Perception.” Association for Psychological Science, October 2018, www.psychologicalscience.org/observer/the-fluidity-of-time. Accessed 12 Jan. 2025.

Eagleman, David M. “Human Time Perception and Its Illusions.” Current Opinion in Neurobiology, vol. 18, no. 2, Apr. 2008, pp. 131-136, www.ncbi.nlm.nih.gov/pmc/articles/PMC2866156/. Accessed 12 Jan. 2025.

Lombardi, Michael A. “Why Is a Minute Divided Into 60 Seconds, an Hour Into 60 Minutes, Yet There Are Only 24 Hours in a Day?” Scientific American, 2019, www.scientificamerican.com/article/experts-time-division-days-hours-minutes/?redirect=1. Accessed 12 Jan. 2025.

Subramaniam, Aditi. “Time Perception: How Our Brains Shape Our Sense of Reality.” Psychology Today, 30 Mar. 2023, www.psychologytoday.com/us/blog/parenting-from-a-neuroscience-perspective/202303/time-perception-how-our-brains-shape-our. Accessed 12 Jan. 2025.

“Temporal Illusions.” Exactly What Is Time?, 2019, www.exactlywhatistime.com/psychology-of-time/temporal-illusions/. Accessed 12 Jan. 2025.

Wearden, John. The Psychology of Time Perception. Palgrave Macmillan, 2016.