question: Why does our perception of time change, depending on what we're doing?
comment: The gist of it is, if you enjoy doing it, time is perceived to speed up. Likewise, if you dislike it or have fear towards it, time is perceived as slow. Also, as you age, your internal perception of time is slower so everything around you relatively seems to speed up [Here's a helpful video explaining the concept]( URL_0 )
passages: The perception of another persons' emotions can also change our sense of time. The theory of embodied mind (or cognition), 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.
  
  Section::::Types of temporal illusions.:Effects of emotional states.:Depression.
   BULLET::::- Evoking emotion: Time can be used to evoke emotions in an interpersonal relationship by communicating the value of the relationship. For example, when someone who you have a close relationship with is late, you may not take it personally, especially if that is characteristic of them. However, if it is a meeting with a total stranger, their disrespect for the value of your time may be taken personally and could even cause you to display negative emotions if and when they do arrive for the meeting.
   The use of time is an important issue in understanding human behavior, education, and travel behavior. Time-use research is a developing field of study. The question concerns how time is allocated across a number of activities (such as time spent at home, at work, shopping, etc.). Time use changes with technology, as the television or the Internet created new opportunities to use time in different ways. However, some aspects of time use are relatively stable over long periods of time, such as the amount of time spent traveling to work, which despite major changes in transport, has been observed to be about 20–30 minutes one-way for a large number of cities over a long period.
   Time has a definite relationship to power. Though power most often refers to the ability to influence people (Guerrero, DeVito & Hecht, 1999, p. 314), power is also related to dominance and status (Guerrero, DeVito & Hecht, 1999, p. 315).
  
  For example, in the workplace, those in a leadership or management position treat time and – by virtue of position – have their time treated differently from those who are of a lower stature position. Anderson and Bowman have identified three specific examples of how chronemics and power converge in the workplace – waiting time, talk time and work time.
   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]".
   The contiguity effect appears relatively constant, and has been predicted to have long-term effects according to the temporal context model proposed by Howard and Kahana. This model explains the contiguity effect in the following manner: when an item is presented, it activates the temporal context that was active when the item was originally studied. Since contexts of neighboring items overlap, and that overlap increases with decreasing lag between items, a contiguity effect results. The contiguity effect has even been found between items in different lists, although it has been speculated that these items could simply be intrusions.
   Section::::Culture and diplomacy.:Influence on global affairs.
  
  Different perceptions of time across cultures can influence global communication. When writing about time perspective, Gonzalez and Zimbardo comment that "There is no more powerful, pervasive influence on how individuals think and cultures interact than our different perspectives on time—the way we learn how we mentally partition time into past, present and future." (Guerrero, DeVito & Hecht, 1999, p. 227)
  
  Depending upon where an individual is from, their perception of time might be that "the clock rules the day" or that "we'll get there when we get there."
   The "shadow of the future" motivates people to encounter others on a more personal level. A chronemic cue is a type of nonverbal cue not filtered out of CMC and indicates how one perceives, uses, or responds to issues of time. Unlike tone of voice, interpersonal distance, or gestures, times is the one nonverbal cue that cannot be filtered out of CMC. For example, a person can send a text message at a certain time of the day and when a response is received he or she can gauge how much time elapsed between messages. Social information processing theory says that a prompt reply signals deference and liking in a new relationship or business context. A delayed response may indicate receptivity and more liking in an intimate relationship; partners who are comfortable with each other do not need to reply as quickly.
   Section::::In music.
   The perception of time seems to be modulated by our recent experiences. Humans typically overestimate the perceived duration of the initial event in a stream of identical events. Initial studies suggested that this oddball-induced “subjective time dilation” expanded the perceived duration of oddball stimuli by 30–50% but subsequent research has reported more modest expansion of around 10% or less, and 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.
   Time perception may speed up as body temperature rises, and slow down as body temperature lowers. This is especially true during stressful events.
  
  Section::::Types of temporal illusions.:Reversal of temporal order judgment.
   Section::::Modulating factors.:Sensory domain.
   Dopamine is also theorized to play a role in the attention deficits present with attention deficit hyperactivity disorder. Specifically, dopaminergic systems are involved in working memory and inhibitory processes, both of which are believed central to ADHD pathology. Children with ADHD have also been found to be significantly impaired on time discrimination tasks (telling the difference between two stimuli of different temporal lengths) and respond earlier on time reproduction tasks (duplicating the duration of a presented stimulus) than controls.
   One common way in which selves may differ in their preferences is they may be modeled as all holding the view that "now" has especially high value compared to any future time. This is sometimes called the "immediacy effect" or "temporal discounting". As a result, the present self will care too much about himself and not enough about his future selves. The self control literature relies heavily on this type of time inconsistency, and it relates to a variety of topics including procrastination, addiction, efforts at weight loss, and saving for retirement.
   Stimulants can lead both humans and rats to overestimate time intervals, while depressants can have the opposite effect. The level of activity in the brain of neurotransmitters such as dopamine and norepinephrine may be the reason for this. 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.
  
  The effect of cannabis on time perception has been studied with inconclusive results.
  
  Section::::Types of temporal illusions.:Effects of body temperature.
   BULLET::::- People display a consistent bias to believe that they will have more time in the future than they have today. Specifically, there is a persistent belief among people that they are "unusually busy in the immediate future, but will become less busy shortly". However, the amount of time you have this week is generally representative of the time you have in future weeks. When people are estimating their time and when deciding if they will make a commitment, they anticipate more "time slack" in future weeks than the present week. Experiments by on this topic showed that people tend to discount investments of time more than money. They nicknamed this the "Yes...Damn!" effect because people tend to commit themselves to time-consuming activities like traveling to a conference under the false impression that they will be less busy in the future.
   Section::::In behavioral economics.
  
  In the context of behavioral economics, time inconsistency is related to how each different self of a decision-maker may have different preferences over current and future choices.
  
  Consider, for example, the following question:
  
  BULLET::::- (a) Which do you prefer, to be given 500 dollars today or 505 dollars tomorrow?
  
  BULLET::::- (b) Which do you prefer, to be given 500 dollars 365 days from now or 505 dollars 366 days from now?
   Section::::Case studies.:"Maison" study.
   When this question is asked, to be time-consistent, one must make the same choice for (b) as for (a). According to George Loewenstein and Drazen Prelec, however, people are not always consistent. People tend to choose "500 dollars today" and "505 dollars 366 days later", which is different from the time-consistent answer.
   Retention and protention
  
  Retention and protention () are key aspects of Edmund Husserl's phenomenology of temporality. 
  
  Section::::Overview.
  
  Our experience of the world is not of a series of unconnected moments. Indeed, it would be impossible to have an experience of the world if we did not have a sense of temporality. That our perception brings an impression to our minds depends upon retention and protention. 
   Psychoactive drugs can alter the judgment 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 a 2007 study, psilocybin was found to significantly impair the ability to reproduce interval durations longer than 2.5 seconds, significantly impair synchronizing motor actions (taps on a computer keyboard) with regularly occurring tones, and impair the ability to keep tempo when asked to tap on a key at a self-paced but consistent interval. 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]".
   BULLET::::- Perceived temporal length of a given task may stretch when broken up or interrupted
  
  BULLET::::- Auditory stimuli may appear to last longer than visual stimuli
  
  BULLET::::- Time durations may appear longer with greater stimulus intensity (e.g., auditory loudness or pitch)
  
  BULLET::::- Simultaneity judgments can be manipulated by repeated exposure to non-simultaneous stimuli
  
  Section::::Types of temporal illusions.:Kappa effect.
   An example of a PRP paradigm might be that there is a task 1 which requires participants to push the keyboard-letter 'n' with the right index finger when a square frame was green. There is also a task 2 which requires participants to push the keyboard-letter 'v' with the left index finger when the digit displayed was a '3' and to push the letter 'c' with the left middle finger if the digit displayed was a '4'. If the temporal distance between the two tasks is varied, for example 150 ms in one and 1000ms in another, the time to respond to the second task will be longer when the interval occurring between the two tasks is 150 ms than when it is 1000 ms. Referring to figure 1, the SLACK intervening between the execution of the first and second task will be absorbed when the interval intervening between the two tasks is long rather than when it is short.
   Short list of types of temporal illusions:
  
  BULLET::::- Telescoping effect: People tend to recall recent events as occurring further back in time than they actually did (backward telescoping) and distant events as occurring more recently than they actually did (forward telescoping).
  
  BULLET::::- Vierordt's law: Shorter intervals tend to be overestimated while longer intervals tend to be underestimated
  
  BULLET::::- Time intervals associated with more changes may be perceived as longer than intervals with fewer changes
  
  BULLET::::- Perceived temporal length of a given task may shorten with greater motivation
   It appears that not only does thinking about actual motion influence people's judgments about time, but thinking about fictive motion has the same effect, suggesting that thinking about one abstract domain may influence people's understanding of another. This raises the question of whether the influence of fictive motion on people's understanding of time is rooted in a concrete, embodied conception of motion, such that both time and fictive motion are ultimately understood in terms of simulations of concrete experience, or whether the effects of fictive motion are a product of the way that language influences thought.
  
  Section::::References.
  