Friend or foe?
If you’re sleep deprived, it can be hard to tell.
A study by researchers at the University of California, Berkeley has found that people are more likely to interpret friendly or neutral faces as threatening when lacking sleep, according to an article on the Medical Xpress website.
In the experiment, young adults viewed a series of facial expressions, once after a full night’s sleep and once after being awake for 24 hours. Brain scans taken during the study revealed that the sleep-deprived brains could not distinguish between threatening and friendly faces.
“They failed our emotional Rorschach (inkblot) test,” says study senior author Matthew Walker, a professor of psychology and neuroscience at UC Berkeley. “Insufficient sleep removes the rose tint to our emotional world, causing an overestimation of threat. This may explain why people who report getting too little sleep are less social and more lonely.”
Consider the implications for sleep-starved groups, such as students pulling all-nighters, emergency-room medical staff, military fighters in war zones and police officers on graveyard shifts, says study lead author Andrea Goldstein-Piekarski, a postdoctoral fellow at Stanford University, who started the study as a doctoral student at UC Berkeley.
Also during the study, researchers found that participants’ quality of rapid eye movement, or dream sleep, correlated with their ability to accurately read facial expressions.
“Dream sleep appears to reset the magnetic north of our emotional compass,” Walker says. “This study provides yet more proof of our essential need for sleep.”
