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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 contracts, objects appearing as moving in a speeding blur[1]. It is generally believed that tachypsychia is induced by a combination of high levels of dopamine and norepinephrine, usually during periods of great physical stress or in violent confrontation.

Physical responses[edit]

Also called the "fight or flight" response of the body to an event our mind considers life-threatening, tachypsychia is believed to include numerous physical changes.

Adrenaline response[edit]

Upon being stimulated by fear or anger, the adrenal medulla may automatically produce the hormone adrenaline directly into the blood stream. This can have various effects on various bodily systems, including:

  • Increased heart rate and blood pressure. It is common for a tachypsychia subject's pulse to rise to between 200 and 300 beats per minute (bpm).[2] Increased heart rate (above 250 bpm) can cause fainting, and the body may adduct all limbs, adopting fetal position, in preparation for a coma.
  • Dilation of the bronchial passages, permitting higher absorption of oxygen.
  • Dilated pupils to allow more light to enter, and visual exclusion—tunnel vision—occurs, allowing greater focus but resulting in the loss of peripheral vision.
  • Release of glucose into the bloodstream, generating extra energy by raising the blood sugar level.[3]

It is common for an individual to experience auditory exclusion or sensitivity. It is also common for individuals to experience an increased pain tolerance, loss of color vision, short term memory loss, decreased fine motor skills, decreased communication skills, or decreased coordination.

Psychological response[edit]

The most common experience during tachypsychia is the feeling that time has either increased or slowed down, brought on by the increased brain activity caused by epinephrine, or the severe decrease in brain activity caused by the "catecholamine washout" occurring after the event. The perception of the duration of an event seems to be modulated by our recent experiences. Humans typically overestimate the perceived duration of the initial event in a stream of identical events[4] and unexpected "oddball" stimuli seem to be perceived as longer in duration, relative to expected or frequently presented "standard" stimuli.[5]

The oddball effect may serve an evolutionarily adapted "alerting" function and is consistent with reports of time slowing down in threatening situations. The effect seems to be strongest for images that are expanding in size on the retina, in other words, that are "looming" or approaching the viewer,[5][6][7] and the effect can be eradicated for oddballs that are contracting or perceived to be receding from the viewer.[6] The effect is also reduced[5] or reversed[7] with a static oddball presented amongst a stream of expanding stimuli.

Initial studies suggested that this oddball-induced “subjective time dilation” expanded the perceived duration of oddball stimuli by 30–50%[5] but subsequent research has reported more modest expansion of around 10%[7][8][9][10] or less.[11] The direction of the effect, whether the viewer perceives an increase or a decrease in duration, also seems to be dependent upon the stimulus used.[11]

It is common for an individual experiencing tachypsychia to have serious misinterpretations of their surroundings during the events, through a combination of their altered perception of time, as well as transient partial color blindness and tunnel vision. After the irregularly high levels of adrenaline consumed during sympathetic nervous system activation, an individual may display signs and symptoms of post-traumatic stress disorder, and it is common for the person to display extreme emotional liability and fatigue, regardless of their actual physical exertion.

Time dilation[edit]

Fear and intense events[edit]

During violent and threatening situations, people often report that things seem to take longer to happen, such as objects falling more slowly.[12]

Possibly related to the oddball effect, research suggests that time seems to slow down for a person during intense events—such as a car accident, a robbery, a chase, skydiving or bungee jumping, a potential predator threat or an intimacy with sexual partner (which would elicit sexual excitement, which in turn release adrenaline),[13] where they're capable of complex thoughts in what would normally be the blink of an eye caused by Fight-or-flight response. This reported slowing in temporal perception may have been evolutionary advantageous because it may have enhanced one's ability to intelligibly make quick decisions in moments that were of critical importance to our survival.[14] 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[15] during the event, or instead an illusion created by the remembering of an emotionally salient event.

An Israeli research team have observed a strong time dilation effect in objects that were looming, but not the retreating, from the subjects. They theorize 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 brought on by the increased brain activity caused by epinephrine, or an adrenaline rush.[16] In such circumstances, an illusion of time dilation could assist an efficacious escape.[17][18] When exposed to a threat, three-year-old children were observed to exhibit a similar tendency to overestimate elapsed time.[19][3]

An experiment from 2007 suggests that the effect appears only at the point of retrospective assessment, rather than occurring simultaneously with events as they happened.[12] Perceptual abilities were tested during a frightening experience - a free fall - by measuring people's sensitivity to flickering stimuli. The results showed that the subjects' temporal resolution was not improved as the frightening event was occurring. Events appear to have taken longer only in retrospect, possibly because memories were being more densely packed during the frightening situation.

However, a meta-analysis[20] by the University of Turku criticizes the logic of the framework proposed in the experiment, pointing out that "if the temporal resolution of all of our visual perceptual processes were [sped] up, then we should have more sensations, snapshots in Stetson et al.’s terminology, than we would have in normal situations". The main issue is that if you truly don't gain speed in mental processing, as proposed in the above framework, "rather than expecting the external world to appear to slow down, one would expect that in these kinds of situations time appears to go faster than normally. An analogous example for this would be modern (action) movies where the editing is done so that one scene is shown only for a brief moment". In contrast, Arstila suggests a framework where cognitive processes are sped up, with the result being a slowed perception of time.

Interestingly, an experiment from 2012[21] demonstrates that effective motor preparation (the paper giving the example of professional athletes[15]) can lead to slowed time perception through enhanced sensory processing, giving some credence to Arstila's framework.

People shown extracts from films known to induce fear often overestimated the elapsed time of a subsequently presented visual stimulus, whereas people shown clips known to evoke feelings of sadness or emotionally-neutral clips from weather forecasts and stock market updates showed no difference. It is argued that fear prompts a state of arousal in the amygdala, which increases the rate of a hypothesised "internal clock." This could be the result of an evolved defensive mechanism triggered by a threatening situation.[22]

Other emotional states[edit]

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.[23] The perception of another persons' emotions can also change our sense of time. The theory of embodied mind (or cognition), as caused by mirror neurons, helps explain how the perception of other people's emotions has the ability to change one's own sense of time. Embodied cognition hinges on an internal process that mimics or simulates another's emotional state. For example, if person #1 spends time with person #2 who speaks and walks incredibly slowly, person #1's internal clock may slow down.

Depression may increase one's ability to perceive time accurately. One study assessed this concept by asking subjects to estimate the amount of time that passed during intervals ranging from 3 seconds to 65 seconds.[24] Results indicated that depressed subjects more accurately estimated the amount of time that had passed than non-depressed patients; non-depressed subjects overestimated the passing of time. This difference was hypothesized to be because depressed subjects focused less on external factors that may skew their judgement of time. The authors termed this hypothesized phenomenon "depressive realism."[24]


A person can experience a long dream which may have seemed to go on for hours, yet, in reality, it actually lasted only a few seconds or maybe minutes.[25]

The perception of time is temporarily suspended during sleep, or more often during REM sleep. This can be attributed to the altered state of consciousness associated with sleep where the person is kept unaware of their surroundings, which would make it difficult to remain informed of the passing of time. When the person awakes in the morning, they have the memory of going to bed the night before, but new memories are rarely made during sleep.

Therefore, upon waking up the following morning it feels as if no time has passed, but the human mind reasons that many hours have elapsed simply because it is now light outside. The passing of time is a relative event brought about by observation of objects (the sun's location, the moon, a clock's time). Without a reference point there would be no context other than day or night. So, as far as time passing faster when during sleep may be due to the lack of reference points that convince the sleeper the time has passed quickly.[26]


Stimulants produce overestimates of time duration, whereas depressants and anesthetics produce underestimates of time duration.[27]

Psychoactive drugs can alter the judgement of time. These include traditional psychedelics such as LSD, psilocybin, and mescaline as well as the dissociative class of psychedelics such as PCP, ketamine and dextromethorphan. At higher doses time may appear to slow down, speed up or seem out of sequence. In 1955, British MP Christopher Mayhew took mescaline hydrochloride in an experiment under the guidance of his friend, Dr Humphry Osmond. On the BBC documentary The Beyond Within, he described that half a dozen times during the experiment, he had "a period of time that didn't end for [him]".

Dopamine has a particularly strong connection with one's perception of time. Drugs that activate dopamine receptors speed up one's perception of time, while dopamine antagonists cause one to feel that time is passing slowly.[19][28]

The effect of cannabis on time perception has been studied with inconclusive results.

See also[edit]


  1. ^ Amato, Ivan (7 June 2018). "When Bad Things Happen in Slow Motion". Nautilus (science magazine). Retrieved 7 June 2018.
  2. ^ Eagleman, D. & Pariyadath, V. (2009). Is subjective duration a signature of coding efficiency? Phil. Trans. R. Soc. B. 364: 1841-1851.
  3. ^ a b Gil S, Droit-Volet S (February 2009). "Time perception, depression and sadness" (PDF). Behavioural Processes. 80 (2): 169–76. doi:10.1016/j.beproc.2008.11.012. PMID 19073237. Archived from the original (PDF) on 2014-01-04.
  4. ^ Rose D, Summers J (1995). "Duration illusions in a train of visual stimuli". Perception. 24 (10): 1177–87. doi:10.1068/p241177. PMID 8577576.
  5. ^ a b c d Tse PU, Intriligator J, Rivest J, Cavanagh P (October 2004). "Attention and the subjective expansion of time". Perception & Psychophysics. 66 (7): 1171–89. doi:10.3758/BF03196844. PMID 15751474.
  6. ^ a b New JJ, Scholl BJ (February 2009). "Subjective time dilation: spatially local, object-based, or a global visual experience?". Journal of Vision. 9 (2): 4.1–11. doi:10.1167/9.2.4. PMID 19271914.
  7. ^ a b c van Wassenhove V, Buonomano DV, Shimojo S, Shams L (January 2008). "Distortions of subjective time perception within and across senses". PLOS ONE. 3 (1): e1437. doi:10.1371/journal.pone.0001437. PMC 2174530. PMID 18197248.
  8. ^ Ulrich R, Nitschke J, Rammsayer T (March 2006). "Perceived duration of expected and unexpected stimuli". Psychological Research. 70 (2): 77–87. doi:10.1007/s00426-004-0195-4. PMID 15609031.
  9. ^ Chen KM, Yeh SL (March 2009). "Asymmetric cross-modal effects in time perception". Acta Psychologica. 130 (3): 225–34. doi:10.1016/j.actpsy.2008.12.008. PMID 19195633.
  10. ^ Seifried T, Ulrich R (January 2010). "Does the asymmetry effect inflate the temporal expansion of odd stimuli?". Psychological Research. 74 (1): 90–8. doi:10.1007/s00426-008-0187-x. PMID 19034503.
  11. ^ a b Aaen-Stockdale C, Hotchkiss J, Heron J, Whitaker D (June 2011). "Perceived time is spatial frequency dependent". Vision Research. 51 (11): 1232–8. doi:10.1016/j.visres.2011.03.019. PMC 3121949. PMID 21477613.
  12. ^ a b Stetson C, Fiesta MP, Eagleman DM (December 2007). "Does time really slow down during a frightening event?". PLOS ONE. 2 (12): e1295. doi:10.1371/journal.pone.0001295. PMC 2110887. PMID 18074019.
  13. ^ Campbell, L. A., and Bryant, R. A. (2007). How time flies: a study of novice skydivers. Behav. Res. Ther. 45, 1389–1392.
  14. ^ Geoghagen, Tom (2007-08-02). "Turn back the clock". BBC News Magazine.
  15. ^ a b Why top sport stars might have 'more time' on the ball by Jonathan Amos Science correspondent, BBC News
  16. ^ Bar-Haim, Y., Kerem, A., Lamy, D., and Zakay, D. (2010). When time slows down: the influence of threat on time perception in anxiety. Cogn. Emot. 24, 255–263.
  17. ^ Tse, P.U., et al. (2004). Attention and the subjective expansion of time. Percept. Psychophys. 66: 1171-1189
  18. ^ Why Time Seems to Slow Down in Emergencies by By Charles Q. Choi, Live Science Contributor
  19. ^ a b Gozlan M (2 Jan 2013). "A stopwatch on the brain's perception of time". theguardian.com. Guardian News and Media Limited. Archived from the original on 4 January 2014. Retrieved 4 January 2014.
  20. ^ Arstila, Valtteri (2012). "Time Slows Down during Accidents". Frontiers in Psychology. 3: 196. doi:10.3389/fpsyg.2012.00196. PMC 3384265. PMID 22754544.
  21. ^ Hagura, Kanai, Orgs, Haggard, Nobuhiro, Ryota, Guido, Patrick (2012). "Ready steady slow: action preparation slows the subjective passage of time". Proceedings of the Royal Society B: Biological Sciences. The Royal Society. 279 (1746): 4399–4406. doi:10.1098/rspb.2012.1339. PMC 3479796. PMID 22951740.CS1 maint: Multiple names: authors list (link)
  22. ^ Droit-Volet S, Fayolle SL, Gil S (2011). "Emotion and time perception: effects of film-induced mood". Frontiers in Integrative Neuroscience. 5: 33. doi:10.3389/fnint.2011.00033. PMC 3152725. PMID 21886610.
  23. ^ Rudd M, Vohs KD, Aaker J (October 2012). "Awe expands people's perception of time, alters decision making, and enhances well-being" (PDF). Psychological Science. 23 (10): 1130–6. CiteSeerX doi:10.1177/0956797612438731. PMID 22886132.
  24. ^ a b Kornbrot DE, Msetfi RM, Grimwood MJ (21 August 2013). "Time perception and depressive realism: judgment type, psychophysical functions and bias". PLOS ONE. 8 (8): e71585. doi:10.1371/journal.pone.0071585. PMC 3749223. PMID 23990960. Lay summaryScience Daily (22 August 2013).
  25. ^ Holcombe, A. O. (2009). Seeing slow and seeing fast: two limits on perception. Trends Cogn. Sci. (Regul. Ed.) 13, 216–221.
  26. ^ "Why does time go so fast when you're asleep?". BBC Science Focus. 7 February 2016. Retrieved 4 July 2018.
  27. ^ Rammsayer T (1989). "Is there a common dopaminergic basis of time perception and reaction time?". Neuropsychobiology. 21 (1): 37–42. doi:10.1159/000118549. PMID 2573003.
  28. ^ Wittmann, Leland, Churan, Paulus, Marc, David, Jan, Martin (2007). "Impaired time perception and motor timing in stimulant-dependent subjects". Drug and Alcohol Dependence. 90 (2–3): 183–192. doi:10.1016/j.drugalcdep.2007.03.005. PMC 1997301. PMID 17434690.CS1 maint: Multiple names: authors list (link)

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