Time perception

Time perception is typically categorized in five distinct ranges, because different ranges of duration are processed in different areas of the brain:

There are many theories and computational models for time perception mechanisms in the brain. William J. Friedman (1993) contrasted two theories of the sense of time:

Another hypothesis involves the brain's subconscious tallying of "pulses" during a specific interval, forming a biological stopwatch. This theory proposes that the brain can run multiple biological stopwatches independently depending on the type of tasks being tracked. The source and nature of the pulses is unclear. They are as yet a metaphor whose correspondence to brain anatomy or physiology is unknown.

The philosophical framework of presentism posits that the perception of time is an emergent property of cognitive dissonance.

The specious present is the time duration wherein a state of consciousness is experienced as being in the present. The term was first introduced by the philosopher E. R. Clay in 1882 (E. Robert Kelly), and was further developed by William James. James defined the specious present to be "the prototype of all conceived times... the short duration of which we are immediately and incessantly sensible". In "Scientific Thought" (1930), C. D. Broad further elaborated on the concept of the specious present and considered that the specious present may be considered as the temporal equivalent of a sensory datum. A version of the concept was used by Edmund Husserl in his works and discussed further by Francisco Varela based on the writings of Husserl, Heidegger, and Merleau-Ponty.

In Greek antiquity, Aristotle connected the awareness of elapsed time with the perception of change. In the Physics, he argued that when a person does not perceive any change, they may not be aware of the passage of time. As an example, he referred to a tradition concerning people in Sardinia who were said to sleep next to the tombs of heroes, upon awakening, to join the later "now" with the earlier one, failing to perceive the interval between them.

Although the perception of time is not associated with a specific sensory system, psychologists and neuroscientists suggest that humans do have a system, or several complementary systems, governing the perception of time. Time perception is handled by a highly distributed system involving the prefrontal cortex, cerebellum and basal ganglia. One particular component, the suprachiasmatic nucleus, is responsible for the circadian (or daily) rhythm, while other cell clusters appear to be capable of shorter (ultradian) timekeeping. There is some evidence that very short (millisecond) durations are processed by dedicated neurons in early sensory parts of the brain.

Warren Meck devised a physiological model for measuring the passage of time. He found the representation of time to be generated by the oscillatory activity of cells in the upper cortex. The frequency of these cells' activity is detected by cells in the dorsal striatum at the base of the forebrain. His model separated explicit timing and implicit timing. Explicit timing is used in estimating the duration of a stimulus. …

In recent history, ecologists and psychologists have been interested in whether and how time is perceived by animals, as well as which functional purposes are served by the ability to perceive time. Studies have demonstrated that many species of animals, including both vertebrates and invertebrates, have cognitive abilities that allow them to estimate and compare time intervals and durations in a similar way to humans.

There is empirical evidence that metabolic rate has an impact on animals' ability to perceive time. In general, it is true within and across taxa that animals of smaller size (such as flies), which have a fast metabolic rate, experience time more slowly than animals of larger size, which have a slow metabolic rate. Researchers suppose that this could be the reason why small-bodied animals are generally better at perceiving time on a small scale, and why they are more agile than larger animals.

In a lab experiment, goldfish were conditioned to receive a light stimulus followed shortly by an aversive electric shock, with a constant time interval between the two stimuli. Test subjects showed an increase in general activity around the time of the electric shock. This response persisted in further trials in which the light stimulus was kept but the electric shock was removed. This suggests that goldfish are able to perceive time intervals and to initiate an avoidance response at the time when they expect the distressing stimulus to happen.

In two separate studies, golden shiners and dwarf inangas demonstrated the ability to associate the availability of food sources to specific locations and times of day, called time-place learning. In contrast, when tested for time-place learning based on predation risk, inangas were unable to associate spatiotemporal patterns to the presence or absence of predators.

In June 2022, researchers reported in Physical Review Letters that salamanders were demonstrating counter-intuitive responses to the arrow of time in how their eyes perceived different stimuli.

When presented with the choice between obtaining food at regular intervals (with a fixed delay between feedings) or at stochastic intervals (with a variable delay between feedings), starlings can discriminate between the two types of intervals and consistently prefer getting food at variable intervals. …

A temporal illusion is a distortion in the perception of time. For example:

Some main types of temporal illusions are as follows:

The Kappa effect or perceptual time dilation is a form of temporal illusion verifiable by experiment. The temporal duration between a sequence of consecutive stimuli is thought to be relatively longer or shorter than its actual elapsed time, due to the spatial/auditory/tactile separation between each consecutive stimuli. The kappa effect can be displayed when considering a journey made in two parts that each take an equal amount of time. When mentally comparing these two sub-journeys, the part that covers more distance may appear to take longer than the part covering less distance, even though they take an equal amount of time.

The perception of space and time undergoes distortions during rapid saccadic eye movements. Chronostasis is a type of temporal illusion in which the first impression following the introduction of a new event or task demand to the brain appears to be extended in time. For example, chronostasis temporarily occurs when fixating on a target stimulus, immediately following a saccade (e.g., quick eye movement). This elicits an overestimation in the temporal duration for which that target stimulus (i.e., postsaccadic stimulus) was perceived. This effect can extend apparent durations by up to 500 ms and is consistent with the idea that the visual system models events prior to perception. The most well-known version of this illusion is known as the stopped-clock illusion, wherein a subject's first impression of the second-hand movement of an analog clock, subsequent to one's directed attention (i.e., saccade) to the clock, is the perception of a slower-than-normal second-hand movement rate (the second-hand of the clock may seemingly temporarily freeze in place after initially looking at it).

The occurrence of chronostasis extends beyond the visual domain into the auditory and tactile domains. In the auditory domain, chronostasis and duration overestimation occur when observing auditory stimuli. One common example is a frequent occurrence when making telephone calls. If, while listening to the phone's dial tone, research subjects move the phone from one ear to the other, the length of time between rings appears longer. …

Tachypsychia is a neurological condition that alters the perception of time, usually induced by physical exertion, drug use, or a traumatic event. For someone affected by tachypsychia, time perceived by the individual either lengthens, making events appear to slow down, or possibly the reverse, with objects appearing as moving in a speeding blur.

Research has suggested the feeling of awe has the ability to expand one's perceptions of time availability. Awe can be characterized as an experience of immense perceptual vastness that coincides with an increase in focus. Consequently, it is conceivable that one's temporal perception would slow down when experiencing awe. The perception of time can differ as people choose between savoring moments and deferring gratification.

Possibly related to the oddball effect, research suggests that time seems to slow down for a person during dangerous events (such as a car accident, a robbery, or when a person perceives a potential predator or mate), or when a person skydives or bungee jumps, where they are capable of complex thoughts in what would normally be the blink of an eye (e.g., a fight-or-flight response). This reported slowing in temporal perception may have been evolutionarily advantageous because it may have enhanced one's ability to intelligibly make quick decisions in moments that were of critical importance to survival. However, even though observers commonly report that time seems to have moved in slow motion during these events, it is unclear whether this is a function of increased time resolution during the event, or instead an illusion created by the remembering of an emotionally salient event.

A strong time dilation effect has been reported for perception of objects that were looming, but not of those retreating, from the viewer, suggesting that the expanding discs — which mimic an approaching object — elicit self-referential processes which act to signal the presence of a possible danger. Anxious people, or those in great fear, experience greater "time dilation" in response to the same threat stimuli due to higher levels of epinephrine, which increases brain activity (an adrenaline rush). In such circumstances, an illusion of time dilation could assist an effective escape. …