Sleep-Deprived People Can't Tell Friends From Enemies, Study Shows, So Stay Away From Social Situations When You're Tired

Science sometimes confirms common knowledge, and sometimes extends it, and that's all well and good. We didn't need a study to tell us that sleep-deprived people are more irritable, but new research sheds further light on the relationship between sleep and social functioning. As it turns out, sleep-deprived people can't tell friends from enemies, so stay away from social situations when you're tired, for crying out loud.

Researchers from the University of California at Berkeley tested this phenomenon by exposing 18 adult experimental participants to images of 70 facial expressions, once when they were fully rested, and then again after they'd been awake for 24 hours. The sleep-deprived participants didn't do a good job of discriminating between the expressions, and their heart rates didn't respond to the faces in the way you'd expect (rising with the unfriendly ones, otherwise not).

As the researchers have published in The Journal of Neuroscience, "sleep deprivation compromises the faithful signaling of, and the 'embodied' reciprocity between, viscerosensory brain and peripheral autonomic body processing of complex social signals." In other words, sleep deprivation ruins your ability to accurately judge the emotional states of others, which is a complicated task requiring your brain and body to be running on all its cylinders.

What are the real-life implications of this research? Well, for starters, you may need to start thinking harder about when it makes sense to trade your sleep time away in the pursuit of some other goal, and why. For instance, it makes little sense to stay up late prepping for a job interview if the lack of rest is going to cause you to misread your interviewer (is there any feeling worse than thinking that someone is scowling at your responses and mentally crossing you off the candidate list?). You might also want to take care to get sufficient sleep prior to any kind of important meeting, whether for business or personal reasons. That impending fight with your significant other won't go any better if you're mistaking their every glance for a frown.

As one of its authors rightly notes, the study has even more critical implications for people like fighters in wartime and police officers on duty in the middle of the night. This study is another piece of evidence that the importance of a good night's sleep can't be overestimated. Enough sleep helps you to fight obesity. Stress and sleep easily get caught in a vicious cycle, where stress leads to less and worse sleep, but less and worse sleep raises stress levels in turn. Sleep is absolutely crucial to athletic performance, but even non-athletes' bodies need recuperation too. Even moderate sleep deprivation makes you act like you're drunk.

The good news, though, is that Americans are getting much more sleep lately than they tend to think they are. Just make sure you're not sabotaging the quality of your sleep with nighttime electronics use, late-in-the-day caffeine, or a sleep-disrupting nightcap. That quality rest will help you to face the world effectively the next day, not just physically but emotionally too.

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