Some people report that in fear-related situations time seems to slowdown. That is to say, for example, during a car crash the event takes much longer from the point of a person experiencing the crash than the observer. But how and why the brain creates this slow motion experience is not completely understood. Recently, on the World Science Festival panel called ‘The Deceptive Watchman: Mind, Brain, and Time’ David Eagleman mentioned his study on the subject, which both intrigued and amused me, so let me tell you why.
In his study Eagleman asked if in a fear situation time slows down because of increased temporal resolution of an experienced event (as when in slow-motion videos a better movement discrimination is seen because of increased number of frames in it). In other words, are people in life-threatening situations somehow able to increase their visual recording of an event, which leads to a more detailed recall and consequent slow motion-like experience?
Here comes the amusing part. To answer the question one obviously needs to place a person in a fear-inducing environment and what is better a way of doing it than a 31m freefall. The participants in this study were dropped from a huge tower in an amusement park and asked to preform a task while free falling (apparently no incentives where given, so I have a suspicion that the study is biased towards fear-junkies ☺ ).
The experimental design was as follows. Firstly, the group has made what they call a perceptual chronometer, which is a device with LED lights that interchangeably shows numbers and their negatives at a set speed. The idea here is similar to a thaumatrope, a kids game in which a piece of paper has two faces with two different drawings if the piece is spun fast enough the two drawings will appear to be merged as one. In the same way, when on the chronometer the number in followed by its negative, at certain speed the two will merge and look like just a square of LED lights. The highest frequency at which the number can still be distinguished defines the temporal threshold. Consequently, if indeed during the life-threatening situation the temporal resolution is increased, then the frequency at which the number can still be named should also increase because better temporal resolution means that you can record more frames in the same amount of time.
While on ground, for all participants their temporal threshold was recorded using the perceptual chronometer. Then they went up the tower and the chronometer was adjusted to flash the numbers 6ms faster then the participant’s temporal threshold. When a person was released from the top of the tower he/she was asked to look at the device and tell if they could identify the number as well as estimate the time the fall took. In addition, each participant observed another person falling and was asked to tell how long did their fall take.
From the data it was determined that people tended to overestimate the time their own fall took by 36%. Consequently, if, as hypothesized the perceived duration of the fall has led to increase in the temporal resolution then the digit identification accuracy should have also increased. However, although the 36% perceived time increase should have an estimated 79% temporal resolution increase, the participants were not able to distinguish the number when falling better than on the ground, i.e. their temporal threshold did not increase.
Therefore, the conclusion is that in fear situations the perceived slowing down of time is not caused by an increase in temporal resolution. Obviously, this does not answer the question- so what does? Well, the authors suggest that this might be linked to emotional memory. Memory and emotions in the brain both come together in the place called amygdala. In a day-to-day situation some things are recorded to memory some are not, by contrast in a situation where emotions are involved, there is an increased amygdala activity and a consequent increase in memory recording. Now, when a person is asked to recall a fear-related event the amount of details that he/she can recall is substantially increased compared to normal situation. However, the brain, not used to recalling so many details, is left to think that the event must have taken longer than it really did.
It is ‘the trick of memory’ as Eagleman puts it; the brain is not used to these exceptional circumstances and therefore, it tricks itself into false time perception.
Stetson C, Fiesta MP, & Eagleman DM (2007). Does time really slow down during a frightening event? PloS one, 2 (12) PMID: 18074019