This post originally appeared on http://www.smopf.com.
I was 10 years old when I first realized that time was speeding up. Summers felt shorter, Christmas came sooner, and the school year passed quicker. I reasoned it out. If my whole life was forever, then a single year was 1/10 of forever. The year before, a single year was 1/9 of forever. 1/9 is a bigger piece of the pie than 1/10 (I had only just learned about fractions), and that’s why time felt slower when I was 9 years old than when I was 10.
But there were a few things I didn’t know back then. Forever is infinity. 1/9 of infinity is not greater than 1/10 of infinity. And then, when I was riding a bicycle at age 27, I was hit by a car making a right turn. I rolled onto the hood and rode on the car for what seemed like several minutes. I started screaming in case the driver hadn’t noticed that she acquired a new hood ornament. The car stopped and launched me into the ground, and when I looked up I realized that we had traveled less than a hundred feet from the turn. For several seconds, time had slowed down. By a lot.
Fractional math is not what causes time to speed up for us as we age. The perception of time is based on what gets recorded to memory. Our memory is like a digital recording of real-time events. However, the sampling frequency may vary. When we experience something new, the brain will sample at a high frequency, recording more data to learn this new thing. When we experience something familiar, the brain doesn’t bother to take as many samples, because it has seen the data before. Playback occurs at a fixed rate. Thus, we perceive a sparse number of samples as a shorter length of time than a dense number of samples. The first time we drive to a new location feels like it takes longer than the second time we make the same drive due to the denser memory samples, even if both memories were recorded in the same amount of time.
When we were kids, every experience was new. Our brains sampled everything at high frequency, remembering dense memories. As we grow older, fewer things are new. The brain doesn’t like to waste memory space, so it won’t record too many samples of routine things. That’s why time flies so quickly for the poor souls trapped in a long-term rat race.
We can still slow time back down. Overwhelm the brain with new experiences and sensations. It will increase the sampling rate to capture this fresh data in memory. Remember all the fantastic new things we faced when we were 10? Dissecting a frog, learning to swim, talking to boys, getting a kitten… If we bombard ourselves with new experiences today, then time will pass as slowly as it did when we were children.
David Eagleman and the Mysteries of the Brain — New Yorker