When You Lose Sleep, Your Brain Can't Read Other People's Emotions

After 24 hours without sleep, the brain begins to overestimate threat.

Sleep is the foundation of our day, and when we don't get enough of it, strange things start happening to our minds and bodies. A new study has found that when we go long enough without sleep, we lose our ability to read facial expressions.


Most Americans don't get enough sleep, trading in those hours of blissful rest so they can work and get to work. Researchers Matthew Walker, a professor of psychology and neuroscience at UC Berkeley, echoed these concerns in a press release, stating that this lack of sleep affects “over two-thirds of people in the developed nations.”

“Recognizing 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."

The experiment was comprised of 18 healthy adults. After receiving a full night's sleep, researchers had them all view 70 different facial expressions ranging from friendly to threatening. Then the researchers had the participants stay awake for 24 hours. The researchers then put the participants through the same test and took measurements of their heart rates and scanned their brains.

The results showed the participants' sleep-deprived brains couldn't distinguish one facial expression from another. MRIs revealed the anterior insula and anterior cingulate cortex — regions of the brain responsible for emotion — had gone dark. The participants tended to perceive most of the expressions they saw as threatening, even the friendly and neutral ones.

Walker added:

“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."

If your friends indicate that you've been a real grouch lately, maybe consider catching a full night's sleep. In her Big Think interview, Arianna Huffington discusses the importance of having a well-rested body and mind:

3D printing might save your life one day. It's transforming medicine and health care.

What can 3D printing do for medicine? The "sky is the limit," says Northwell Health researcher Dr. Todd Goldstein.

Northwell Health
Sponsored by Northwell Health
  • Medical professionals are currently using 3D printers to create prosthetics and patient-specific organ models that doctors can use to prepare for surgery.
  • Eventually, scientists hope to print patient-specific organs that can be transplanted safely into the human body.
  • Northwell Health, New York State's largest health care provider, is pioneering 3D printing in medicine in three key ways.
Keep reading Show less

Apple CEO Tim Cook calls for graduates to overcome "political noise" and algorithms

Cook's commencement speech at Tulane University urges students to take action.

Getty Images
Technology & Innovation
  • Apple CEO Tim Cook gave a commencement speech at Tulane University on May 18th.
  • Cook cautioned the graduates to not get caught up in echo chambers and algorithms.
  • He acknowledged the failures of his generation.
Keep reading Show less

Why the south of Westeros is the north of Ireland

As Game of Thrones ends, a revealing resolution to its perplexing geography.

Image: YouTube / Doosh
Strange Maps
  • The fantasy world of Game of Thrones was inspired by real places and events.
  • But the map of Westeros is a good example of the perplexing relation between fantasy and reality.
  • Like Britain, it has a Wall in the North, but the map only really clicks into place if you add Ireland.
Keep reading Show less

Behold, firm evidence — at last — that ultra-processed food causes weight gain

Junk food causes weight gain, but it's not just about the calories.

Photo Illustration by Justin Sullivan / Getty Images
Surprising Science

We know we should eat less junk food, such as crisps, industrially made pizzas and sugar-sweetened drinks, because of their high calorie content.

Keep reading Show less