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

 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

 '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

 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