Lack of Sleep Makes You More Selfish

Lack of Sleep Makes You More Selfish

Another fascinating study from UC Berkeley that investigates the link between lack of sleep and generosity

In our last post, we discussed findings from a UC Berkeley study that demonstrated how sleep-deprived subjects not only felt lonelier but also avoided close contact in much the same way as people with social anxiety. So, in a nutshell, insomnia can kill your social life and even trigger a disturbing “viral contagion of social isolation.”

However, these researchers weren’t finished exploring the adverse social effects of poor sleep because they published another fascinating study last summer that investigates the link between sleep loss and generosity. These findings are especially relevant this time of year, a.k.a. the holiday season, when Salvation Army red kettles and Toys for Tots boxes join the fray of holiday shoppers to remind the masses of the less fortunate. After all, ‘tis the season of joy and giving – which comes easier to the sleep-fortunate.

Tell me more.

So how does sleep affect the giving spirit? The report (1) that sparked the conversation was published in PLOS Biology and summarized findings from three separate studies led by UC Berkeley research scientist Eti Ben Simon and UC Berkeley professor of psychology Matthew Walker. 

According to the authors, the report adds to “a growing body of evidence demonstrating that inadequate sleep not only harms the mental and physical well-being of an individual but also compromises the bonds between individuals — and even the altruistic sentiment of an entire nation.” Ouch.

Show me the figgy pudding.

The proof, as we say, is in the pudding, so let’s break down the three studies that assessed the impact of sleep loss on people’s willingness to help others and subsequently support the link between lack of sleep and selfishness. 

Study #1

In this scenario, scientists placed 24 healthy volunteers in a functional magnetic resonance imager (a.k.a. an MRI). The machine scanned their brains after a full night’s sleep (8 hours) and a night without sleep. They found that areas of the brain that form the “theory of mind network” – which engages when people empathize with others or try to understand other people’s wants and needs – were less active after the sleepless night. 

“It’s as though these parts of the brain fail to respond when we are trying to interact with other people after not getting enough sleep,” remarked Simon.

Study #2

In the second study, the researchers tracked more than 100 people online over three or four nights to measure the subjects’ quality of sleep, including how long they slept and how many times they woke up.  Afterward, the researchers assessed the subject’s desire to help others, such as holding an elevator door open for someone else, volunteering, or helping an injured stranger on the street.

The results found that a decrease in the quality of a subject’s sleep from one night to the next indicated a significant decline in the desire to help others from one subsequent day to the next. “Those with poor sleep the night prior were the ones that reported being less willing and keen to help others the following day,” explained Simon.

Study #3

The third and final part of the research involved examining a database of 3 million charitable donations in the US from 2001 to 2016, particularly around Daylight Savings Time when many are robbed of an hour of sleep.

The findings? The study established a 10% drop in donations for participants that “fell back” and lost an hour of sleep due to the time change. However, the same giving decline did not occur in regions of the country that did not 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,” Walker explains.

Take Away.

As unabashed sleep advocates, we are obsessed with sleep research, particularly around health and wellness. These findings add another step to our soapbox – sleep matters more than you can imagine. As we revel in the merriment of the holiday season and complete another turn around the sun, why not resolve to make sleep a priority in the new year?

Our site,, is full of tips for improving sleep and other fascinating research for the sleep curious. If you’re ready to get serious about sleep and work toward improving your total wellness, bookmark our blog for regular sleep-friendly news, updates, and tips.

Cheers to a better night’s sleep and a new year full of quality ZZZs, friends!



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