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Time flies? For bigger-bodied animals with slower metabolic rates, it may feel that way

8730739154_7a2706fd27I've often wondered why time seems to tick by at a faster tempo for adults than it does for children. As a child, I stared at the clock in my classroom willing the second hand to hurry along. As an adult, I can't seem to get enough hours in the day.

Now, a study published in the journal Animal Behavior may offer a possible explanation: Scientists discovered that an animal's body size and metabolic rate may influence the way they perceive the passage of time.

The research team, led by Andrew Jackson, PhD, an assistant professor of zoology from Trinity College in Dublin, was curious to know if different animals perceive changes in their surroundings at the same rate. To investigate this question, they compared how fast an animal's eyes can process changes in its surroundings using a measure called critical flicker fusion frequency (CFF). Animals with high CFF values are able to detect rapid changes in the environment.

The team compared the CFF values, body weights, temperatures, and metabolic rates of 34 different species of animals ranging from rodents to humans. They found that smaller-bodied animals with faster metabolisms were able to detect rapid changes in the environment that larger animals with slower metabolic rates couldn’t.

As a story in the Telegraph explains, the speed at which animals detect change in their environment could affect how they perceive time. From the piece:

Interestingly, there's a large difference between big and small species. Animals smaller than us see the world in slo-mo. It seems to be almost a fact of life.

“Our focus was on vertebrates, but if you look at flies, they can perceive light flickering up to four times faster than we can.

"You can imagine a fly literally seeing everything in slow motion."

The effect may also account for the way time seems to speed up as we get older, Dr Jackson said.


"It's tempting to think that for children time moves more slowly than it does for grown ups, and there is some evidence that it might," he said.

"People have shown in humans that flicker fusion frequency is related to a person's subjective perception of time, and it changes with age. It's certainly faster in children."

Will time feel like it's flitting by faster and faster as we age? It's a little too soon to say. The research team writes that additional studies are needed to understand the mechanism(s) that influence how animals perceive changes over time before the significance of this study can be fully understood.

Holly MacCormick is a writing intern in the medical school’s Office of Communication & Public Affairs. She is a graduate student in ecology and evolutionary biology at University of California-Santa Cruz.

Previously: The mind maps the visual world with minimal means
Photo by Robert Couse-Baker

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