Think back to life in 2020, when the COVID-19 pandemic prompted governments to impose travel restrictions, lockdowns, and other measures meant to keep people safe from a then-novel virus rampaging around the world. You, like many others, probably felt that time was passing slower than ever before when you were living without many of the forms of human contact that had previously filled everyday life.

Now, a large team of scientists from around the world has captured what it was like to live in “Blursday,” as they call it: to have it feel as though time ground to a halt due to feelings of isolation. They published those findings, alongside other effects of distorted time perception too slight for an individual to notice, last week (August 15) in Nature Human Behavior.

The Scientist spoke with coauthor Maximilien Chaumon, a researcher at the Institut du Cerveau et de la Moelle Épinière (ICM) in France, about how he pulled together the various kinds of data on time perception—largely from online survey data conducted in nine countries during the first two years of the pandemic—that were included in the Blursday database, which other scientists can now freely access online alongside the 14 questionnaires and 15 behavioral tasks used to gather the data.

By the way, Chaumon adds, the team decided on the name Blursday after coauthor Virginie van Wassenhove looked up the term on Urban Dictionary. According to that entry, Blursday originated as a term for a day lost due to a persistent hangover—but it was widely used in early 2020 to describe a feeling of days becoming indistinguishable from one another.

The Scientist: Where did the idea to perform these tests and generate this database originally come from?

Maximilien Chaumon headshot

Maximilien Chaumon: Time perception is not a sense in a classical way. When we talk about our senses, [not] our sense of time but our sense of vision, touch, and so on, we think about those sensory receptors. And time perception does not have such receptors. It is a psychological construct, actually, that has a very multifactorial origin that is very complex. And it was the Timing Research Forum that started this project, and especially [study coauthor] Virginie van Wassenhove.

See “How Time Is Encoded in Memories

COVID struck Virginie as an opportunity to finally get a huge amount of data on this very complex cognitive construct. Basically, it is known that our sense of time is highly influenced by the environment, by our emotional state, by our physiology, by circadian rhythms, our state of isolation, and so on. And these effects have also effects on our wellbeing and possibly our mental health. This is sort of the angle that triggered this study, in the sense that this massive disruption that COVID-19 created, with its lockdown, on our daily routine, the way we use our time, the way time unfolds during the day, and initial reports of people reporting being lost in their week, not knowing whether it was today or whether it was Monday or Tuesday and so on. You may have experienced that yourself.

TS: I still do, yeah.

MC: You remember how it was during the early days. And so basically, Virginie, right at the time when we stopped being locked down in France, initiated this massive set of measures, trying to tackle all of the possible aspects of our time perception and our sense of time in general. You may have seen in the paper . . . we have a huge list of many different tasks set up to measure different aspects of our sense of time, and some general questionnaires as well, and tasks that tackle some more well-known psychological scales, like depression, anxiety, and so on. The idea was to basically then correlate these tasks and measures throughout many countries.

The idea behind this paper is to say, “Okay, now that we have this huge data set, we cannot analyze it all ourselves.” All of the contributors of the papers, its 30 authors, each of them has brought one task or one questionnaire or a bunch of them and started analyzing things themselves. This is where I jumped in, offering to gather the data, put the data together, and provide this small server that allows anyone to access [the database] on a web browser. The main goal behind the paper was basically to say, “We want this data open” and make it available for the community to study—and also to showcase a few results.

TS: In general, you found that isolation led to an increasingly warped perception of time, right? Can you walk me through some of the tests you conducted to determine that?

MC: Well, all those questionnaires are very well-known questionnaires that have scales, and that have been measured and benchmarked for a long time. We really mostly picked those that we needed for a specific question.

Now, in terms of isolation, it was one of the items of one questionnaire. So we don’t have any specific analysis related to isolation, strictly speaking. But the sense of subjective confinement was computed based on the answers of several of these scales, [combined] in order to obtain a scale, going from feeling very lonely to feeling not so lonely, and each of them were based on some specific psychological tests.

See “How Social Isolation Affects the Brain

We look at a very well-known effect in psychology . . . which is [based on] when people are asked retrospectively to estimate how much time has elapsed since a given landmark. . . . After a random number of tasks, suddenly we asked them, “Okay, how long do you think you’ve been connected to this experiment today?” And they gave us an estimate. This estimate varied between one minute and three hours or even more, but we removed some of the very long durations, which we deemed unreliable. And so, what happens when you do this is you can map how much time has actually elapsed and how much they think has elapsed, okay, and you can map the two measures against each other. And you see here a very classical effect: that people tend to slightly overestimate short durations and underestimate higher durations. . . . plus [we] add the effects of confinement on it. Under confinement, people tended to overestimate less the shorter durations, and vice versa for the long durations. . . . We see that the more stringent the lockdown was, the shorter the relative estimation of duration was, so the lower this ratio between duration estimate and actual clock duration was.

It is known that our sense of time is highly influenced by the environment, by our emotional state, by our physiology, by circadian rhythms, our state of isolation, and so on.

We have some interesting effects here that show basically a proof of principle that it’s possible to do some actual measures with these data.

TS: Given your specific role in pulling together this Blursday database and making it available to the public, how do you see you, your coauthors, or other researchers, using it? Are there specific questions that are easier to answer now?

MC: I think this is really for scientists who have a hypothesis to test. Scientists will need to be sort of already in the field in order to be interested in these things. These are quite specific values, so psychologists will know some of these scales and may have questions about [them]. We [used] many very classical tasks; perhaps you know about this task: It’s the tendency to discard rewards that are going to be gathered later in the future, compared to [an] immediate reward. This is a very general task that lots of scientists interested in decision-making, for example, use. One of them may end up looking at this paper and [wondering], “Oh, is there an effect of the isolation of the participant on their ability to discount or discount less in that case?” That’s an easy question, perhaps. I just made it up, though.

TS: Have you gotten any inquiries from researchers who are interested in the data yet?

MC: So far? No. . . . I think people can actually get the data very easily from the database; there’s the address in the paper, and you don’t need us to actually get the data. And that was the goal. My involvement in this project is [making it so] more people are able to do this without me. This kind of project can otherwise last so long, and the data is so complex. That’s also why I kind of organized it in a way that could be extended if some new data were to come. But people can use it without asking us [for specific data], which can easily become a nightmare.

TS: Are you still collecting new data for the measures that you have?

MC: There’s no data collection at the moment, as far as I know. But all of the protocols are available online. Free of charge, of course, and people are very welcome to contact us if they want some more information.

Editor’s note: This interview has been edited for brevity.