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"O magic sleep! O comfortable bird,
That broodest o’er the troubled sea of the mind
Till it is hushed and smooth!"
John Keats wrote these lines in his poem Endymion in 1818, celebrating the tranquility and restorative power of sleep, likening it to a bird that calms the mind. Despite our love for sleep though, most of us don't get enough of it. Insufficient sleep negatively impacts our mood, memory, and cognitive performance. It also leads to errors and even accidents because it affects our ability to pay attention.
In today's digital era, sleep deprivation is widespread among Americans. A recent Gallup poll revealed that 57% of respondents don't get enough sleep. Comparing this to the past, in 1942, 59% of people reported sleeping eight or more hours per night, and only 3% reported getting five hours or less. In 2024, only 26% report getting eight or more hours of sleep, while 20% get five hours or less. That’s quite a difference.
When we lose sleep for one night, we still have cognitive reserves that we can draw on. But when we fail to get enough sleep over consecutive days, then our cognitive reserves keep depleting. We’re not able to restore them sufficiently. We then accrue sleep debt, which is the cumulative loss of sleep over days. As sleep debt mounts, so does the pressure to sleep. We crave it. In other words, just as we might get further and further into monetary debt with mounting problems, we can also get further and further into sleep debt where we drain our cognitive resources. A large sleep debt results in negative mood, weight gain, poor physical and mental performance, and various health issues.
Sleep debt can build by staying up later than our optimal bedtime, yet we likely still have to wake up the same time—often with an alarm. Physiological reasons, such as stress or untreated sleep disorders, can contribute to sleep debt. Poor time management skills can also contribute to it, when we have to catch up with work in the evenings to meet deadlines. TV-binge watching, surfing the web or watching TikTok videos can also delay bedtime. Each person's sleep debt is unique, depending on their sleep needs, which is typically 7-9 hours of quality sleep per night.
For years it was believed that screen time and exposure to blue light hindered sleep. Now, scientists are not so sure. But what about the opposite relationship? Does poor sleep affect how we use our devices? And what about sleep debt?
The Gallup poll findings highlight how sleep-deprived our culture is. We also know that research shows that lack of sleep affects our ability to pay attention. How then might sleep debt translate into what we do on our computers, tablets and smartphones? It seems reasonable to predict that sleep deprivation, which leads to cognitive fatigue, would make it harder for us to focus and sustain our attention while using our devices. Information workers spend much of their day using devices because their main activities involve dealing with digital information.
My students and I set out to investigate how insufficient sleep affects our ability to pay attention when using our devices. Fortunately, we had access to a population that is notorious for getting poor sleep: college students. We conducted our experiment in “a living laboratory”, i.e. in the wild, where we studied people’s actual behavior in their real-world environments. We asked the students to install software on their computers and smartphones enabling us to log their digital activity and observe precisely what they were doing on their devices, and for exactly how long. All data was kept private.
The students also kept sleep diaries, recording their bed times and wake times daily. Sleep diaries are still widely used in clinical research studies and correlate highly with sleep sensing devices. We tracked sleep and device usage for 76 students for seven days. Using a standard mathematical formula, we calculated sleep debt.
What did we find? As we expected, nearly all students accumulated sleep debt. We found that as sleep debt mounted, the students’ behavior on their devices changed. It turns out that as sleep debt grows, so does the time spent on social media. In other words, with consecutive days of not getting the sleep they need, the students devoted more and more attention to social media. We controlled for deadlines and workload, meaning that regardless of whether students had deadlines or how much work they had to do, we still found that sleep debt still correlated with increased social media usage.
Why is this the case? We had our own thoughts about why, but we interviewed the students to gain their perspectives. Here are what two students said, representative of most students.
“it's easy to just scroll through Reddit. Just mindless behavior. Like procrastination time.”
“And it's just easy. Scroll down, open a funny picture, move on to the next thing.”
These responses highlight how browsing social media is easy behavior. If a person is physically tired, they are also low on cognitive resources. When our cognitive resources are low, we do what’s easy and lightweight, and for many young people especially, it happens to be browsing social media.
There are many reasons for why people use social media: boredom, habit, or seeking quick rewards, like when watching a funny TikTok video. We discovered another trigger: tiredness. People might go on social media when they are simply tired. Especially when sleep-deprived, people lack cognitive resources to do demanding tasks and stay focused. Social media, being lightweight and requiring minimal mental effort, becomes an easy choice.
Young people are the highest users of social media. When older individuals are mentally fatigued, they may do some other activity online or offline, like reading, watching TV, or playing a simple crossword puzzle. Spending a few minutes a day on social media or a mindless game can help us take a break from hard work. The problem is when people can’t pull away from such activities and go down rabbit holes—that’s when they become problematic.
The relationship between sleep debt and social media use can be cyclical. More sleep debt leads to more social media use, and increased social media use, especially at night, can result in less sleep, creating a vicious pattern.
What can we do? The most important step is to establish a regular sleep pattern: go to bed and wake up at the same time every day. The National Sleep Foundation recommends 7 to 9 hours of sleep each night. Naps can help alleviate sleep debt and will be more refreshing than using social media. Regular sleep patterns are essential to combating sleep debt. Stop using your devices as part of your bedtime routine to break the sleep debt cycle. Above all, avoid checking your smartphone during the night.
Better quality sleep alone cannot guarantee that young people will spend less time on social media, as many other factors influence social media use. However, maintaining good cognitive reserves through adequate sleep is beneficial for both mind and body.
You can read more about sleep debt and our cognitive resources in my book Attention Span.