BLURSDAY: Studying the sense of time during the COVID-19 pandemic

We provide a rich database for investigating the nature of the altered sense of time that was experienced by many people during the COVID-19 pandemic lockdown. Based on these data, we show that the feeling of isolation may have led to the slower passage of time during the lockdown.
BLURSDAY: Studying the sense of time during the COVID-19 pandemic

The sense of time is inherent to our subjective and perceptual experience of our surroundings. Our temporalities are supported by at least two internal timekeeping systems that operate at different timescales. For instance, our sleep-wake cycle, body temperature, and diet are tightly guided by the circadian clocks that run automatically and constantly in the background. This is precisely why we experience jet lag after a flight between different time zones; our post-flight behavioral and metabolic functions are regulated by internal clocks that have not yet fully entrained to the dark-light cycle of the new time zone. The precision and automaticity of the circadian clock indeed come at the expense of its inflexibility and thus, we cannot use the circadian clock to arbitrarily keep track of intervals in seconds to minutes range (e.g., for timing traffic lights, estimating the arrival time of an approaching car). Our and other animals’ brains are endowed with a separate internal stopwatch mechanism for such timing tasks that require perceiving, remembering, and adaptively organizing behaviors around intervals in seconds to minutes range (i.e., interval timing). Crucially, our sense of time is “plastic”: subjective time elapses at different speeds depending on our arousal level and psychological state. Maybe the best example of the plasticity of time perception is the vast underestimation of the duration of their gameplay by children.  

Why is all this relevant for you? Because virtually the entire human population was subject to anti-COVID-19 pandemic-related confinement measures that have substantially affected not only our psychological well-being, social relations, and cognitive health (Fiorenzato et al., 2021), but also vastly altered our sense of time in various ways, according to a recently published international study (Chaumon et al., 2022). After some period of being locked into our dwellings with no-to-minimal in-person socialization and having disrupted daily routines, most people started to mix up the days of the week or had difficulty scheduling their personal and professional activities. English-speaking communities started to use terms such as “Blursday” to refer to the blurred sense of time during the pandemic. But most of these conclusions were based on unsystematic observations, anecdotes, and vivid personal experiences and could not be addressed based on robust, well-controlled study designs. The effects of isolation on temporal cognition are understudied, and gathering observations in ecological and societal settings such as this historical episode is essential (van Wassenhove, 2022). Only a few research studies reported difficulty in temporal orientation during the pandemic. For example, Cellini et al. (2020) reported that participants had difficulty keeping track of hours-day and had a dilated sense of time that was attributed to boredom during the lockdown (see also Cravo et al., 2021; Loose et al., 2020). In other studies, participants reported that time elapsed slower during the pandemic, which was again attributed to boredom and sadness or bidirectional distortions of subjective time that was associated with stress (Droit-Volet et al., 2020; 2021; Martinelli et al., 2020; Ogden, 2020; 2021). But none of these studies could address the causes of distorted subjective time, had the necessary control data, or used a rich-enough set of experimental tasks and questionnaires, which could provide a multifactorial and multicultural assessment of the situation. Most importantly, because of the uniqueness of the event, a historical record covering distinct temporal phenomenologies is needed to be acquired and ultimately support subsequent controls and additional data in addition to longitudinal tracking. Crucially, studying how our sense of time changed during the pandemic requires testing the same sensorimotor, perceptual, and cognitive functions using identical tasks with similar apparatus both during lockdowns and out of them. 

Only if we knew about the upcoming pandemic, would we have collected the control data earlier (we would more likely do other things that more directly affected our lives) and already have a definitive answer to this interesting question that relates to our personal experience during the pandemic. The problem is that none of us saw the pandemic coming and, thus, did not have the necessary normative behavioral benchmarks. But, if time perception was assessed during the pandemic then the control data could be collected post-pandemic (even years later) and compared to data collected during the lockdown.

An international group of researchers came together to achieve this long-term aim and conducted the research presented in the current paper. We tested hundreds of participants (during the lockdown in 2020 and outside lockdown in 2021) from nine different countries located on four continents during the strict confinement measures. We tested participants through many different online behavioral experiments to address different aspects of interval timing (e.g., motor and cognitive timing) and cognition (e.g., working memory, decision-making), collected their responses to different questionnaires (e.g., personality, time orientation), demographics and confinement indices. Importantly, we make this comprehensive dataset, as well as the online research tools used to collect these data in different languages accessible to the research community for investigating the factors that underlie pandemic-related distortions of subjective time (Figure 1).

We showcase the useability of the database in the current paper. For instance, we found that the feeling of isolation more than isolation itself may have led to the slower passage of time and resulted in larger subjective distances between the moment at which participants were tested, and past/future events. We also discovered that when participants were asked to retrospectively (make a time judgment about an event that has already happened) judge the duration of a lapse of time, they overestimated durations shorter than 15-20 minutes and underestimated durations longer than 15-20 minutes reflecting a systematic bias in the perception of time intervals. Interestingly, this bias was less pronounced during the lockdown and outside confinement. These are just a few examples illustrating how Blursday can be exploited to pin down the individual factors that were differentially affected by isolation and why our sense of time was warped during the confinement.

Blursday Database Server Screenshot

Figure 1. A screenshot from the Blursday data server. Data can be easily filtered, visualized, and downloaded through this live data server at

The Blursday dataset will serve as a systematic historical record of distortions of subjective time during the Covid-19 pandemic and help future studies set out to use and build on the same tools to assess the effects of social isolation on temporal information processing post-pandemic.

Would you like to be a part of this international effort? The database is fully open-access and you can even perform one or all tasks constitutive of the Blursday test battery to append additional control datasets. Simply visit:


Cellini, N., Canale, N., Mioni, G., & Costa, S. (2020) Changes in sleep pattern, sense of time and digital media use during COVID-19 lockdown in Italy. Journal of Sleep Research 29, e13074.

Fiorenzato, E., Zabberoni, S., Costa, A., & Cona, G. (2021). Cognitive and mental health changes and their vulnerability factors related to COVID-19 lockdown in Italy. PLOS ONE 16, e0246204.

Chaumon, M., Rioux, P.-A., Herbst, S., Spiousas, I., Kübel, S., Gallego Hiroyasu, E., Runyun, S., Micillo, L., Thanopoulos, V., Mendoza-Durán, E., Wagelmans, A., Mudumba, R., Tachmatzidou, R., Cellini, N., D’Argembeau, A., Giersch, A., Grondin, S., Gronfier, C., Alvarez Igarzábal, F., Klarsfeld, A., Jovanovic, L., Laje, R., Lannelongue, E., Mioni, G., Nicolaï, C., Srinivasan, N., Sugiyama, S., Wittmann, M., Yotsumoto, Y., Vatakis, A.,  Balci, F., van Wassenhove, V. (2022). The Blursday Database: Individuals’ Temporalities in Covid Times. Nature Human Behaviour doi: 10.1038/s41562-022-01419-2

van Wassenhove, V. (2022). Temporal disorientations and distortions during isolation. Neuroscience & Biobehavioral Reviews 137, 104644.

Droit-Volet, S. et al. (2020). Time and Covid-19 stress in the lockdown situation: Time free,«Dying» of boredom and sadness. PloS one 15, e0236465.

Droit-Volet, S. et al. (2021). The persistence of slowed time experience during the COVID-19 pandemic: Two longitudinal studies in France. Frontiers in Psychology 12, 721716.

Martinelli, N. et al. (2020). Time and emotion in the lockdown for the Covid-19 epidemic: The determinants of our experience of time? Frontiers in Psychology 11, 3738.

Ogden, R. (2021). Distortions to the passage of time during England’s second national lockdown: A role for depression. Plos one 16, e0250412.

Ogden, R. (2020). The passage of time during the UK Covid-19 lockdown. Plos one 15, e0235871.

Loose, T., Wittmann, M., & Vásquez-Echeverría, A. (2022). Disrupting times in the wake of the pandemic: Dispositional time attitudes, time perception and temporal focus. Time & Society 31, 110-132

Cravo, A. M. et al. (2021). Time experience in social isolation: A longitudinal study during the first months of COVID-19 pandemic in Brazil. Science Advances 8, 15.

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