Why does time seem to pass quickly when you’re having fun?

Time flies when you’re having fun. Why does that happen? A new study provides interesting insight into how the brain perceives the passage of time.

A study published in Current Biology suggests that our perception of time is actually based on our experiences, rather than an accurate internal clock.

Researchers at the University of Nevada, Las Vegas (UNLV) used brain scans that zoomed in on the anterior cingulate cortex (ACC), a brain region important for monitoring activity and tracking experiences. They analyzed brain patterns as they tasked rodents with repetitive movements. Some rodents had to respond to the same prompt more than 200 times.

The researchers knew from previous research that our brain patterns are similar but not exactly the same each time we perform a repetitive movement. So they looked to see if these subtle differences in brain pattern changes corresponded to the first and 200th movement in a series.

The study found that brain activity changed detectably from beginning to end as the task progressed, regardless of the speed of movement. This pattern remained consistent when analyzed with a machine learning model, indicating that experience, not time intervals, drove the changes in neural activity.

“When we’re still and bored, time passes very slowly because nothing is happening or doing anything,” said Dr. James Hyman, an assistant professor of psychology and the study’s senior author. “In contrast, when there’s a lot going on, each bit of activity propels our brain forward. And if that’s how our brain objectively tells time, the more we do and the more things happen to us, the faster time passes.”

“If you want to remember something, slowing down and taking breaks between activities can help,” he said. “Conversely, doing an activity at a fast pace can help you perceive the activity passing more quickly,” he added. “The more you do, the faster time passes. People say time passes quickly when you’re having fun, but it’s not about having fun, it’s about doing a lot.”

“We believe that our brains are synchronized to the clock of our devices to keep track of time, counting every second as it passes. But that’s not quite right,” the researchers said. “We tell time from our own experience, from what we do and what happens to us.”