There’s less than a month to go before daylight saving time. The first Sunday in November is arguably America’s crankiest, save for Arizona and Hawaii (the two states that no longer participate in turning the clocks back). And now, new research suggests that Americans are less generous around this time of year because they’re not getting enough sleep.
In a study published in PLOS Biology and conducted at the University of California Berkeley, researchers ran a set of three tests to see if sleep has a negative effect not just on individuals, but on society as a whole.
A Closer Look at the Research
In the first test, researchers performed brain scans on 24 healthy volunteers — none of whom were allowed to have caffeine or alcohol — after they all had a full eight hours of sleep. Then, the researchers performed a second set of scans after the volunteers had a night of no sleep. All the participants, except one, were far less likely to want to help others after sleep deprivation. In addition, that lack of desire was reflected in the MRIs. Areas of the brain related to empathy and social cues were a lot less active in the second set of scans.
In the second test, researchers wanted to examine sleep deprivation and its relationship to generosity in a more realistic setting. They tracked 136 volunteers over four consecutive nights. Volunteers self-reported how many hours they slept each night and how many times they woke up during the night. Every morning, they completed a short questionnaire to assess their “helping behavior.”
In the third test, the study authors decided to look at the effects of sleep deprivation on a nationwide scale. They collected data on three million charitable donations in the US between 2001 and 2016. Here’s the kicker: On average, the number of donations dropped by 10 percent after daylight saving time. That same drop was not seen in parts of the country that don’t change their clocks.
“Even a very modest ‘dose’ of sleep deprivation — here, just the loss of one single hour of sleep opportunity linked to daylight saving time — has a very measurable and very real impact on people’s generosity and, therefore, how we function as a connected society,” Matthew Walker, a UC Berkeley professor of psychology, said in a press release. “When people lose one hour of sleep, there’s a clear hit on our innate human kindness and our motivation to help other people in need.”
Why Sleep Impacts Our Willingness to Help
Aside from what we already know — that sleep deprivation puts us in a bad mood — why might a lack of sleep make us less generous? The authors state that sleep loss impairs a set of brain regions known as the “social cognition network.” This network helps a person process information about social situations.
“Pro-social helping of various kinds consistently engages … the social cognition network,” the authors write. “This network is activated when considering the mental states, needs, and perspectives of others, and the active choice to help them.” And when it isn’t functioning properly? It leads to “a loss of both empathy and the withdrawal of compassionate helping.”
As with every study, this one had limitations. The volunteers for tests one and two completed questionnaires to determine their generosity levels; however, answering questions about social scenarios is a lot different than experiencing real-life scenarios. For example, one question asked: “Imagine you are on a crowded bus and an elderly person gets on. What would you do?” Sleep-deprived people were more likely to say they’d reluctantly help or wouldn’t help at all. In a real-life scenario, however, those same sleep-deprived people may feel a lot more pressure to give up their seat.
The Bottom Line
While more research is needed to link better sleep health to an empathetic society, this study shines light on how important sleep is — not just for you, but for the people around you.
Wondering how to improve your sleep quality? Check out these tricks to boost your rest, or try meditating and reading before your head hits the pillow. And if you’re going to make any charitable donations this year, do it before the first Sunday in November!