This study examines the impact of sleep deprivation on cognitive function, decision-making and economic outcomes.
Sleep deprivation is known to cause a variety of adverse effects on cognition and health. However, we know relatively little about the relationship between acute or chronic sleep deprivation and economic outcomes and decision-making. Furthermore, sleep patterns in developing countries remain largely unexplored, despite many environmental factors which have the potential to interfere with regular sleep.
In this study, the research team used detailed wireless sleep measurement technologies and applied lab-in-the-field techniques to: 1) measure the prevalence and causes of sleep deprivation among low-income individuals, 2) assess the effectiveness of interventions to alleviate sleep deprivation in a real-world environment, and 3) estimate the causal impact of reduced sleep deprivation on cognitive function, decision-making, and economic outcomes.
In the randomized evaluation, the treatment group received interventions to improve their sleep at home as well as a brief nap during the day, while the control arm followed their standard sleep habits. All participants engaged in a battery of laboratory tasks measuring cognitive function, decision-making, and productivity weekly throughout the study as well as provided daily measures of sleep patterns, labor market outcomes, and cognitive function.
The study finds that low-income adults in Chennai sleep only 5.5 hours per night on average despite spending 8 hours in bed. Their sleep is highly interrupted, with sleep efficiency—sleep per time in bed—comparable to those with disorders such as sleep apnea or insomnia. A randomized three week treatment providing information, encouragement, and improvements to home sleep environments increased sleep duration by 27 minutes per night by inducing more time in bed. Contrary to expert predictions and a large body of sleep research, increased nighttime sleep had no detectable effects on cognition, productivity, decision-making, or well-being, and led to small decreases in labor supply.
Improving sleep quality could potentially generate both more sleep (due to higher sleep efficiency) and higher benefits from each minute of sleep. Identifying interventions to improve sleep efficiency in contexts like ours, and testing whether increased sleep efficiency unlocks the benefits found in sleep research in rich countries would also be valuable. It could also be that the benefits of increased night sleep manifest over longer time horizons. Consistent with the hypothesis that increased sleep can have meaningful effects, we find the nap treatment has a significant positive effect on an overall index of outcomes, with positive effects on productivity, well-being and cognition.