Things that Yarom knows: how does time fly when you're having fun?

C wonders: How is it that time sometimes stands still and sometimes it runs?

About 370 years ago, Galileo Galilei noticed that the chandelier hanging from the ceiling of the church swings so that it always completes an oscillation at the same time: both when it swings quickly along a long arc and when it moves slowly along a short arc. The cycle time depends only on the length of the wire connecting it to the ceiling. A few decades later, Huygens connected a tensioned gear wheel to the pendulum whose movement was stopped by a moveable stop.

This is how the pendulum clock was born: an oscillating weight provides a constant rhythm and allows the wheel to move one "step" in each cycle so that the rotation of the wheel counts the number of oscillations of the pendulum. From grandfather's pendulum clock, through the quartz clock to state-of-the-art atomic clocks, these two fundamental components will be found in every clock: a rhythm generator that operates in regular cycles and a counter that counts the number of oscillations. According to an accepted model for the internal clock (scalar expectancy theory) these clock components also exist in our nervous system. In fact, it is not one watch, but several watches that satisfy the need to evaluate different periods of time from thousandths of a second to years. One clock is the one that dictates sleep and wakefulness throughout the day and its rhythm generator is the rotation of the earth around its axis. But in your question, C. you aimed at other clocks: the stopwatches that count seconds and minutes. The "pendulum" is nerve cells that emit signals at a constant rate, a "switch" is activated at the beginning of an event that requires time estimation and a neural mechanism in the brain "accumulates" the signals.

The next part of the clock is parallel to the board on which the hands move and the hours are indicated, that is, a mechanism that translates the number of signals for a known time (second, minute, hour). Every baby creates in his memory the clock face, that is, a database of periods of time in relation to which the time measured in each event is compared. This mechanism is not unique to humans: every animal must have an internal clock to coordinate muscle action and make decisions regarding its immediate environment, for example to assess the danger posed by a madman or the chance of success in hunting. Correct time allocation is also essential for the production and understanding of speech and music. Estimating time is an essential element in the decision-making process: the time to wait for a reward is calculated as part of the price paid for it, and it is possible that what distinguishes impulsive people from those who are able to "delay gratification" is the rhythm of the internal clock. When impulsive people, such as those suffering from attention and concentration disorders, estimate the duration of a period of time or limit a short period of time, they extend the duration of time as longer or pace it as shorter. A similar phenomenon is found in people who suffered damage to the Orbitofrontal Cortex, an area involved in prediction and considerations of harm-benefit following a new stimulus. Evolution did give us precise mechanisms for measuring time, but at the same time equally complex mechanisms to cheat this clock. A state of heightened alertness accelerates the ticking rate of the clock so that more beats are counted in the same period of time, which means more psychological time is compressed into the same unit of physical time, this is probably the mechanism that distorts the sense of time in a cocaine trip and also when we suffer from a fever. It is also possible to allow the neural pendulum to swing at a constant rate but to interfere with the mechanism that counts the oscillations. When a large investment of attention to the environment is required, some signals may not be counted. Since the processing of a visual stimulus (image) requires more attention than the processing of a sound, the duration of viewing the image will be seen as shorter than the same duration of listening to the sound. When we are less interested in the external world and are focused on monitoring the passing of time, for example in a boring work session, then every "pendulum swing" is counted and the time experienced is lengthened. Another way to influence the sense of time is analogous to moving the hands on a physical clock so that the starting point of the measurement changes in retrospect. Adrenaline, which is secreted in situations of danger and distress, omits from memory some of the beats that were counted and thus makes us feel that time is running out and running out quickly. In a study in which subjects were asked to estimate the length of time an image was projected on a screen, it turned out that the feeling of time lengthened when the subject himself activated the software - the signals began to be counted from the moment of the decision to press the button. But why should Mother Nature, who created for us clocks accurate enough to notice slight deviations in the rhythm of music and coordinate subtle muscle movements, also bother to provide us with tools to cheat the clock?

It turns out that there are cases in which an overly accurate watch may be harmful. In the following simple experiment you can catch the brain "hot" by cheating time. Go to the mirror and look at your face reflected in it. Focus your gaze on the right eye for a few seconds and then switch to focus on the left eye. Whoever looks in the mirror with you will see the eye spinning, but not you! In the character in the mirror the eyes are fixed and there is no way to watch this move. This is an essential mechanism: the eyeball is unstable, it moves in rapid oscillations (saccades) whose purpose is to bring different objects in front of the sensitive area of ​​the retina (fovea).

Apparently, the "film" provided by the visual system was supposed to appear as if it was taken with a video camera held in the hand of a drunk riding a bicycle on a bumpy road. We see a stable and calm world because the system is deceiving: it cuts from the film blurry images captured during a fast eye movement and shows us a time image from which a few thousandths of a second have been censored from time to time. In fact this time warp starts even before the eye actually moves in preparation for the jump to come. Subjects evaluated the duration of stimuli presented for 2 tenths of a second before or after the movement of the eye as much shorter than those stimuli presented when the eye is steady.

Emotions will also cause contraction or stretching of time. Adrenaline, as you remember, causes the erasure of time signals and thus causes us to count fewer seconds in each minute and the pace of events is perceived as faster. This sense of urgency energizes us to take action and increases the chance of getting out of danger safely. When strong emotions arise, the speed of producing time signals increases for a short period of time: voices with emotional meaning (crying, for example) played for several seconds will be heard longer than neutral voices and negative voices will be heard as more prolonged than positive voices. Our clock is sophisticated enough to return to a normal rhythm in about 4 seconds. 

Similarly, eye contact with an angry person will seem longer than viewing the same face wearing any other expression. Looking at faces that express fear will also be felt as longer, while expressions such as disgust or guilt, which are also universal, will not cause the observer a bias in the sense of time. There is logic in these reactions: anger in the other person is a sign that we should be prepared for trouble, an expression of fear may stem from a danger that threatens us as well, and in any case the possibility that a quick action is required causes an acceleration of the rate of production of nerve signals and therefore an extension of the subjective time. Disgust is, as I remember, a strong and survival emotion no less than fear, but it obliges us not to act but rather to avoid (eating or contact) and therefore does not require resetting the clock.

At an average reading rate (250 words per minute), reading this article took a little less than 4 minutes: if you felt that only 3 minutes had passed, I probably succeeded, those who had time stretched to 5 minutes or more probably did not bother to get this far.

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