Incentives to Sleep

Motivation: Sleep deprivation is considered one of the most prevalent risky behaviors in modern societies. This paper investigates whether monetary incentives can be used to promote healthier sleep habits.

Data: We collected detailed data drawn from wearable sleep trackers (Fitbits), time-use surveys and self-reported sleep. A total of 180 participants volunteered for the experiment.The experiment was conducted during term time at the University of Oxford. Each term lasts for 8 weeks. Recruitment was done in Week 0. Subjects were invited to the lab for an experimental session and obtained a Fitbit Charge HR device in Week 1. They received experimental surveys and tasks starting Monday of Week 2, and were monitored until Week 8. On Friday of Week 8, they returned the devices and received final payments. During the first survey we collected demographic information and self-reported information on sleep, health, and time-use. We also elicited time and risk preferences using incentivized tasks.

Methods: During weeks 3-6 of the experiment, we randomized monetary incentives. Subjects were asked to select a target bedtime and sleep duration. Individuals achieving their target time were rewarded either 2.5 or 5 GBP. Individuals missing a target would lose 2 GBP per night -deducted from the other payments of the experiment.

Results: Our results show that individuals respond to monetary incentives to sleep.Treated subjects were 14% more likely to sleep between 7 and 9 hours (the recommended amount of sleep), and less likely to sleep less than 7 hours. We also find evidence for improvements in sleep quality.The size and the frequency of the incentives are crucial to sustain the healthy behavior after the intervention. Our results hold to the inclusion of individual fixed effects, we compare individual's sleep patterns throughout the study period.We find evidence of sophisticated hyperbolic discounting. Individual demanded commitment devices (e.g., early bedtime targets, or contract involving more severe punishment).Furthermore, our results show evidence of self-serving bias. Individuals over (under)-estimated own sleep quality (risk associated with shorter sleep duration) with respect to that of their peers.Finally, treated subjects reported a lower resting heart rate, were more likely to engage in more intensive activities, and reported an improvement in their academic performance (in class percentile