In previous work, Giuntella et al. (Proc Natl Acad Sci 118:e2016632118, 2021), we documented large disruptions to physical activity, sleep, time use and mental health among young adults at the onset of the COVID-19 pandemic in Spring 2020. This study explores the trends 1 year into COVID-19, as vaccines began to roll out, COVID-19 deaths declined, and social distancing measures eased in the United States. We combine biometric and survey data from multiple cohorts of college students spanning Spring 2019 through Spring 2021 (N = 1179). Our results show persistent impacts of the pandemic on physical activity and mental health. One year into the pandemic, daily steps averaged about 6300 per day compared to about 9800 per day prior to the pandemic, a 35% decline. Almost half of participants were at risk of clinical depression compared to a little over one-third prior to the pandemic, a 36% increase. The impacts on screen time, social interactions and sleep duration at the onset of COVID-19 largely dissipated over the course of the pandemic, though screen time remained significantly higher than pre-pandemic levels. In contrast to the sharp changes in lifestyle and mental health documented as the pandemic emerged in March 2020, we do not find evidence of behavioral changes or improvements in mental well-being over the course of Spring 2021 as the pandemic eased.

In a field experiment, we studied the performance of an incentive scheme that combines a lottery-based reward for compliance with probabilistic sanctions for noncompliance. For one month, bus passengers who purchased a ticket on board a subset of buses operating in a medium-sized Italian city participated in a lottery awarding a €500 prize. The remaining buses—otherwise identical—were used as controls. We observed the amount of tickets sold on treated and control buses over three months, before, during, and after the introduction of the lottery. Results show that treated buses sold significantly more on-board tickets than control buses during the lottery period. In our setup, the estimated extra revenues from the ticket sales caused by the introduction of the lottery fell short of the amount of the total prizes raffled off. However, the incentive scheme proved cost-effective because not all the lottery prizes were claimed by winners. This paper was accepted by Uri Gneezy, behavioral economics.

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