The negative consequences of lack of sleep go beyond the individual level, as a study makes clear: people who have not had enough sleep are comparatively unhelpful, research results of mental attitudes as well as neurological and social indications suggest. Sleep thus has a meaning for a fundamentally important aspect of human coexistence, say the scientists.
You can’t do without it: Many studies show that sleep is of central importance for the physical and mental abilities of people. Impairments in sleep health are associated with correspondingly complex problems. For example, the tendency to develop cardiovascular diseases or diabetes increases and the general risk of death increases. In addition, lack of sleep is known to be linked to depression and many other mental health issues. In this context, there were already indications that some mental effects negatively influence certain aspects of human social behavior. “More and more studies are showing that when you don’t get enough sleep, not only does your well-being suffer, but your entire social environment can be affected, including strangers,” says Eti Ben Simon of the University of California at Berkeley.
In this context, Ben Simon and her colleagues focused on one aspect of the so-called prosocial behavior of people: In three research approaches, they investigated the extent to which lack of sleep affects the willingness of those affected to help other people. In the first sub-study, the scientists recorded the individual level of helpfulness of 24 healthy volunteers using a question system on altruism, as well as their brain activity using functional magnetic resonance imaging (fMRI). These investigations were carried out after a night of normal sleep and later after a night of sleep deprivation.
Changed attitude, brain activity and willingness to donate
It was shown that after the sleep deprivation, the individual level of helpfulness had dropped significantly. The cause seemed to be reflected in the results of the fMRI investigations, the researchers report: It became apparent that the brain regions that have a function within the so-called “Theory of Mind” network were less active after a sleepless night . “When we think about other people, this network is activated and allows us to understand the needs of others: what are they thinking about right now? Are you having problems? Do they need help?” explains Ben Simon. “The function of this network appeared impaired after sleep deprivation. It seemed like these parts of the brain didn’t respond when we tried to interact with other people after we didn’t get enough sleep.”
In the second part of the study, the team collected information online from more than 100 study participants. The individual level of willingness to help was also recorded for them using the special question system. This happened repeatedly after several nights in which the subjects had reported on their sleep length and quality. “We found that overnight deterioration in sleep quality predicted an overnight decrease in the desire to help other people,” reports Ben Simon. Specifically: “Those who had slept poorly the night before reported that they were less ready and less willing to help others the next day,” says Simon.
Social dimensions
In the third part of the study, the team analyzed a database of information about charitable donations in the United States between 2001 and 2016. The focus of the researchers was on the day after the changeover to daylight saving time – i.e. after the night in which an hour of sleep time is lost. The statistical evaluations showed that there was always a drop in donations of around ten percent. In the regions of the country where the clocks were not changed, however, this decline in willingness to donate was not observed. So it makes sense: “Even a very modest dose of sleep deprivation — in this case, just the loss of a single hour — appears to have a measurable effect on people’s generosity, and therefore on how we function as a connected society,” says senior author Matthew Walker.
The bottom line is that the results show that lack of sleep has a significant negative effect on people’s willingness to help, the scientists conclude. This aspect fits with previous research that shows that people who are sleep deprived distance themselves from others. “Overall, lack of sleep leads to more antisocial individuals, which has multiple consequences for our coexistence as a social species,” Walker said. The potentially considerable social significance also becomes clear against the background that in industrialized countries more than half of all people state that they get too little sleep during the working week. “Fostering sleep could thus help to better shape the social bonds we all experience every day,” says Ben Simon.
Source: University of California – Berkeley, professional article: PLoS Biology, doi:10.1371/journal.pbio.3001733