Lack of sleep has been linked to heart diseasebad mood and lonelinessSerial number: 11/15/16). Being tired could also make us less generousresearchers report Aug. 23 in PLOS Biology.
The hour of sleep lost in the switch to daylight saving time each spring appears to reduce people’s tendency to help others, researchers found in one of three experiments testing the link between sleep loss and generosity. Specifically, they showed that average donations to a US-based nonprofit were down about 10 percent in the business week after the time change compared to the four weeks before and after the change. change. In Arizona and Hawaii, states that do not observe daylight saving time, donations were unchanged.
With more than half of people living in parts of the developed world reporting that they rarely get enough sleep during the workweek, the finding has implications beyond the week ahead, the researchers say.
“Sleep deprivation shapes the social experiences we have [and] the kinds of societies we live in,” says neuroscientist Eti Ben Simon of the University of California, Berkeley.
To test the link between sleep loss and generosity, Ben Simon and his team first brought 23 young adults into the lab for two nights. The participants slept through one night and stayed awake another night.
In the mornings, the participants completed a standardized altruism questionnaire that rated their likelihood of helping strangers or acquaintances in various scenarios. For example, participants rated themselves on a scale of 1 to 5, with 1 being least likely to help and 5 being most likely to either give up their seat on a bus to a stranger or offer a ride to a co-worker who I needed it. Participants never read the same scenario more than once. About 80 percent of the participants were less likely to help others when not sleeping than when they were resting.
The researchers then looked at the participants’ brain activity in an fMRI machine, comparing each participant’s neural activity in a state of rest versus sleep deprivation. That showed that sleep deprivation reduced activity in a network of brain regions linked to the ability to empathize with others.
In another experiment, researchers recruited 136 participants online and asked them to keep a sleep log for four nights. Then, each participant completed subsets of the altruism questionnaire before 1 p.m. the next day. The researchers found that the more time participants spent awake in bed, a measure of sleep deprivation, the lower their altruism scores. That drop in altruism held up both when comparing individuals to themselves and when averaging the scores for the entire group.
In the final experiment focused on daylight saving time, the researchers looked at charitable donations from 2001 to 2016 to Donors Choose, a nonprofit organization that raises money for school projects across the United States. When the team excluded Hawaii and Arizona, as well as outliers such as very large donations, more than 3.4 million donations remained. In the business week that followed the time change, total donations, which typically averaged about $82 a day, dropped to about $73 a day, says Ben Simon.
There’s always the possibility that some other variable besides sleep is causing this drop in generosity, says behavioral economist David Dickinson of Appalachian State University in Boone, NC. But this “triple methodology approach” allowed the researchers to draw a compelling line between changes in the brain. that appear during sleep deprivation to real-world behavior. “This puts a fuller story on how poor sleep affects decisions in this domain of helping others,” he says.
chronic sleep deprivation in the modern world it is a serious problem, says Ben Simon (Serial number: 1/3/19). But unlike many other large-scale problems, think climate change or political polarization, this one has a ready solution. “If you think about promoting sleep and allowing people to get the sleep they need, what impact could that have on the societies that we live in?”