Time perception
William J. Friedman (1993) contrasted two theories of the sense of time:[6][7][8] Another hypothesis involves the brain's subconscious tallying of "pulses" during a specific interval, forming a biological stopwatch.
[16] 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.
[19][20][21] In the popular essay "Brain Time", David Eagleman explains that different types of sensory information (auditory, tactile, visual, etc.)
He goes on to say, "This brief waiting period allows the visual system to discount the various delays imposed by the early stages; however, it has the disadvantage of pushing perception into the past.
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.
[29] 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.
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 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.
[35] After training, lab subjects were successfully able to peck specific keys at different times of day (morning or afternoon) in exchange for food, even after their sleep/wake cycle was artificially shifted.
[36] However, a more recent study on time-place learning in pigeons suggests that for a similar task, test subjects will switch to a non-circadian timing mechanism when possible to save energy resources.
[43] When returning to the hive with nectar, forager honey bees need to know the current ratio of nectar-collecting to nectar-processing rates in the colony.
[48] In a single study, colonies from three species of ants from the genus Myrmica were trained to associate feeding sessions with different times.
[57] 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.
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.
[61] In an experiment, participants were told to stare at an "x" symbol on a computer screen whereby a moving blue doughnut-like ring repeatedly circled the fixed "x" point.
In the attempt to disprove the first hypothesis, David Eagleman conducted an experiment in which the moving ring suddenly reverses direction to spin in the other way as the flashed object briefly appears.
A recent study tries to reconcile these different approaches by treating perception as an inference mechanism aiming at describing what is happening at the present time.
[70] This oddball effect may serve an evolutionarily adapted "alerting" function and is consistent with reports of time slowing down in threatening situations.
Initial studies suggested that this oddball-induced "subjective time dilation" expanded the perceived duration of oddball stimuli by 30–50%[71] but subsequent research has reported more modest expansion of around 10%[73][74][75][76] or less.
[77] Numerous experimental findings suggest that temporal order judgments of actions preceding effects can be reversed under special circumstances.
In an experiment conducted by David Eagleman, a temporal order judgment reversal was induced in subjects by exposing them to delayed motor consequences.
[78] In an experiment conducted by Haggard and colleagues in 2002, participants pressed a button that triggered a flash of light at a distance, after a slight delay of 100 milliseconds.
[79] By repeatedly engaging in this act, participants had adapted to the delay (i.e., they experienced a gradual shortening in the perceived time interval between pressing the button and seeing the flash of light).
Additionally, when the experimenters slightly reduced the delay, and shortened the spatial distance between the button and the flash of light, participants had often claimed again to have experienced the effect before the cause.
[88] 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 our survival.
[91] 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).
[96] Other researchers[97][98] suggest that additional variables could lead to a different state of consciousness in which altered time perception does occur during an event.
Children have to be extremely engaged (i.e. dedicate many neural resources or significant brain power) in the present moment because they must constantly reconfigure their mental models of the world to assimilate it and manage behaviour properly.
[114] The effect of cannabis on time perception has been studied with inconclusive results mainly due to methodological variations and the paucity of research.
[117] Using PET scans it was observed that participants who showed a decrease in cerebellar blood flow (CBF) also had a significant alteration in time sense.
