Can Sleepless Nights Really Lead To Selfish Behavior?

We've all heard about the importance of sleep for our overall health. More than 35% of adults in the United States get less than the minimum of seven hours of sleep per night, as per the Centers for Disease Control and Prevention. Those who aren't sleeping enough are more likely to suffer from health conditions, such as a heart attack, stroke, depression, or diabetes. In fact, losing sleep for just one night can affect how we impact society, specifically whether or not we want to help others, according to a new study in PLOS Biology.

The researchers based their study on the social cognition network in the brain. When it's active, we consider the needs and perspectives of other people and are more likely to help them. If this part of our brain is inactive or somehow wounded, we lose empathy and compassion for others. The lack of sleep can also disrupt this social cognition network and interfere with how we process our emotions and the emotions of others.

The first experiment of the study used a functional MRI to compare the participants' brain activity after a full night of rest versus a night of no sleep. They measured whether or not the participants were more or less likely to help strangers or people familiar to them. When participants had no sleep, the brain's social cognition network was less active compared to when they had sufficient sleep. They also were less likely to offer help to others.

To study the effect of sleep in a more real-world environment, the researchers asked more than 100 participants to keep a diary of their sleep (per recent study). Each day, the participants answered questionnaires about their helping intentions and behavior. When the participants had poor quality of sleep, they were less likely to help others. Even if a participant had helped a person the day before, a single night of poor sleep dampened the intention to help the next day.

Turning the clocks forward each spring during daylight savings time also influences our prosocial behavior. The researchers looked at more than 3 million charitable donations from 2001 to 2016 and found up to a 10% dip in donations the week around daylight savings time. The two states that don't adjust their clocks — Arizona and Hawaii — didn't see this drop in donations. Perhaps an extra hour of sleep makes you more charitable? Nevertheless, researchers didn't find a significant increase in donations when the United States returned to its standard time.