My alarm woke me up at 7:00 a.m.
I turned off the alarm and went back to sleep.
When I opened my eyes again, I remembered that I had just had a very long dream.
Oh no. At least an hour must have passed, right? I must be late!
But when I looked at the clock—huh? Why is it only 7:10?
I’m sure you’ve had an experience like the one above, right?
Time seems to pass more slowly in dreams. One day in waking life, three years in a dream.
As a subjective experience, this strange phenomenon definitely exists. Academically speaking, though, it’s highly controversial, and there’s still no consensus.
In 2007, a paper was published in the top academic journal Science: Scientists first let mice play in an amusement park for 50 minutes, recording the wave patterns of activity in their cerebral cortex with electrodes. Then they let the mice sleep.
They found that the mice’s cortical activity during play while awake was replayed during sleep. This showed that the mice had dreamed about playing. Even more remarkably, the replayed cortical activity in the dream ran at 6-7 times the speed of the activity while they were awake.
Faster neural activity in dreams means that, over the same length of time, the brain can experience more things. So isn’t this basically ‘a few minutes in waking life, an hour in a dream’?
But this study has two major flaws: 1. Mice aren’t humans, so we can’t simply generalize the findings to human dreams; 2. Cortical activity isn’t necessarily the same thing as subjective dream experience. So this experiment can only serve as indirect evidence.
Other evidence, meanwhile, suggests that slower time passing in dreams simply doesn’t exist.
One scientist had the brilliant idea of using lucid dreams—dreams in which you realize that you’re dreaming—to investigate the speed of time passing in dreams. Researchers recruited expert lucid dreamers who could control their dreams, and asked them to count at what they subjectively believed was the same speed in waking life and in dreams—for example, counting from 1 to 10 in both states.
Because they could send signals from inside their dreams, the researchers arranged for them to signal the start and end of counting in a dream by moving one eye each time. That way, the researchers could record how long it took them to count from 1 to 10 in a dream.
The result: counting took an average of 11.1 seconds in a dream, compared with 8.9 seconds while awake. Overall, the difference was not statistically significant. Time passing in dreams and in waking life was no different.
However, this study also had an obvious flaw: a lucid dream is a very unusual kind of dream. Perhaps precisely because it is so close to being awake, the subjective feeling of slower time passing disappears.
In short, there’s still no consensus on whether this strange phenomenon exists or what causes it. What do you think?
Note
- This article from the Psychology New Knowledge Mini-Class series was a short popular-science essay/ramble written to accompany Zhichao Wei: Psychology New Knowledge Course. It was published on the now-closed platform Fantuan, and the original link no longer exists.
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