New research from the University of California-Berkeley shows that our judgement to read facial expressions is impaired with not enough sleep. Sleep deprived study participants were less able to accurately assess facial expressions than when they had a full night's rest, the research found.
For the study, which was published in the Journal of Neuroscience, 18 healthy young adults viewed 70 facial expressions that ranged from friendly to threatening - once after a full night of sleep, and once after being awake for 24 hours.
'Recognising the emotional expressions of someone else changes everything about whether or not you decide to interact with them, and in return, whether they interact with you,' said senior study author Matthew Walker, a professor of psychology and neuroscience.
'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.'
He added that the findings were 'especially worrying considering that two-thirds of people in the developed nations fail to get sufficient sleep.'
MRI scans were taken of the participants' brains during the study, which revealed that sleep-deprivation affects the emotion-sensing regions of parts of the brain, known as the anterior insula and anterior cingulate cortex.
The participants' heart rates were also measured and the researchers found that they did not respond normally to threatening or friendly facial expressions.
If you aren't getting enough sleep, check out Dr Nerina's Sleep Toolkit