When we were children, many of us experienced the illusion that summers or other periods of time were much longer than how we perceive the passage of a similar amount of time in adulthood. Now, a team of scientists led by Eötvös Loránd University in Hungary has investigated empirically whether the perception of time changes with age and, if so, how and why.
The experts enrolled a cohort of participants from three age groups (4-5, 9-10, and above 18 years old) and asked them to watch two one-minute long videos. The samples were extracted from a popular animated series, and were balanced in visual and acoustic features, expect for one feature – eventfulness. While one clip consisted of a rapid succession of events (a policemen rescuing animals and then arresting a thief), the other was a monotonous, repetitive sequence (six prisoners escaping on a rowing boat). After watching the videos, the participants were asked which was longer.
The answers revealed that, while two-thirds of the pre-kindergartners perceived the eventful video as longer, three-fourths of the adults felt the same thing about the uneventful one. The middle group, in which participants expressed a similar but more moderate bias than the adults, helped researchers estimate a shift in time perception occurring around the age of seven.
To explain these differences in time perception between age groups, the experts relied upon the concept of “heuristics,” which was introduced in Cognitive Science by Amos Tversky and Daniel Kahneman, and refers to our ability to use mental shortcuts or proxies to help us make fast decisions. Since our brain does not have a reliable central clock or a direct sensory mapping of durations (unlike in the case of distances or pitch), we must use a proxy to get a handle on temporal passage.
According to the scientists, children use a “representativeness heuristics” to measure time. For instance, they ask themselves which video they can talk more about.
Since the eventful video was packed with actions and consisted of several episodes, they could talk more about it and they thus felt that it was longer. However, between six to ten years of age, children learn the concept of “absolute” or “universal” time, which is conceptualized as a physical entity independent of the events that it connects, and can help us make appointments, organize our tasks, and follow timelines by clocking the time.
With such a development, our representativeness heuristics for measuring time changes into a “sampling heuristics,” which helps us check the flow of time by frequently sampling it, for instance, by looking at a clock or watching the traffic flow.
Thus, as adults, when we watch a captivating movie, our mind becomes highly immersed in the story, while during a boring movie, we are going to repeatedly check our watch or think about something else, and all of these distractions will enable us to sample the flow of absolute time.
According to the researchers, these two types of heuristics can explain the rather bizarre switch at about age seven and give rise to the persistent bias that uneventful meetings, for example, are much longer than they actually are. However, more research is needed to properly understand the mystery of time and how our minds can make sense of it.
The study is published in the journal Nature Scientific Reports.
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