The start of the COVID-19 pandemic seems like a lifetime ago to some, and just yesterday to others. Scientists are beginning to unpack the way people processed the passage of time amidst the stress, uncertainty and isolation of the 1 year, 8 months and 21 days since WHO declared a pandemic.

Why it matters: The pandemic's global effects on how people experience time could provide new insights into the brain's ability to perceive and predict time — a fundamental feature of life.

• The brain tells time at multiple scales — from tens of microseconds to hours, months and years.
• The mechanisms at the shortest and longest time scales are better understood than those behind the minutes, hours and weeks that tick by in between, says Rodrigo Laje, a neuroscientist who studies time perception at the National University of Quilmes in Argentina. It's those time scales that frame the pandemic experience.

What they found: One study conducted with online questionnaires in April 2020 by Ruth Ogden, an experimental psychologist at Liverpool John Moores University, found more than 80% of participants felt that time was distorted.

• For about half of the people in the study — those who were older, felt socially isolated or stressed, or had fewer tasks to accomplish — time slowed down. But it passed more quickly for those who tended to be younger and more socially satisfied.

"We don't have a simple, clear narrative of what is happening," Laje says.

• He's part of a consortium of researchers using online questions and timing tasks to study how social isolation affected time perception in about 2,500 participants in 10 countries.
• Early findings, not yet published, indicate time distortion was more affected by how confined people felt, versus how confined they were by measures limiting social interaction.
• Weeks and months seemed to pass slowly for most people, but hours and minutes weren't affected. "It might be that confinement didn’t change our short-term functioning," says Laje. "We still had to go to the bathroom, still had to type or write, and still had to cook."

The intrigue: Pandemic time has been distorted across cultures, but differences have emerged.

• In Iraq, participants in a recent study by Ogden and her colleagues that is under peer review consistently reported that days and weeks passed slowly.
• In Argentina, slightly more people said time passed more quickly than slowly, she says.
• In France, time felt slower for participants in two recent studies, because of what the authors described as "a persistent feeling of boredom characteristic of a depressive state that has taken hold in the population."

What else may drive those cross-cultural differences — from the stringency of public health measures in different countries to the way time is imagined and described by different cultures — is still being teased apart.

How it works: Memories play a key role in how people judge the length of a period of time, Ogden says. Make more of these markers of time and the brain assumes more time has passed.

• Without memory-making trips, weddings, graduations and other events during the past two years, people may feel they've been robbed of the memories that moor the brain and expect time to feel like it is passing more quickly.

Yes, but: "It's more subtle," says Ogden. "We haven’t formed memories we want to form — we’ve built a whole new social structure and way of life. That has been taxing, and so it feels like a long time for lots of people."

• And so time plods on.

The big picture: If people spend months in a cave or days in a bunker without sunrises, clocks or other cues, they will unsurprisingly lose track of time.

• But Ogden says while we all had "watches and clocks" during the pandemic, "we still have lots of distortions."
• The pandemic has underscored that time is attached to experiences, emotions and thoughts, she says, adding the large-scale, real-world studies of time perception during the pandemic could inform approaches to studying the neurobiology of time.
• "Time is a facet of something else," she says. "It’s much more integrated with our sensory experience and our consciousness."

What to watch: A big question is whether the pandemic will still feel long years from now when many of the new social rules may be abandoned and forgotten, says Ogden.

The bottom line: The pandemic has made us aware that how we’re using our time affects how we feel about time, she says.

• "There are real potential benefits for well-being, mental health and quality of life in asking, 'How does my time make me feel?'"

Editor's note: This story has been corrected to reflect that the hours, days and months time scales are not medium time scales.