Five Hours of Sleep a Night Biases People Toward Negative Interpretations

We all know that nothing good comes from cutting sleep out of your life.

First, there are the cognitive effects. Sleep deprivation influences people’s performance in ways similar to alcohol consumption, which is what makes drowsy driving similarly dangerous to drunk driving.

Then there’s the simple feeling of tiredness, having to get through the day when your eyelids want to fall shut. Not fun.

But another consequence of inadequate sleep that sometimes gets lost in the mix is the emotional effect. Not getting enough sleep interferes with the brain’s ability to process emotions, as a new study published in the Journal of Sleep Research highlights.

In the study, 42 participants were asked to participate in a two-week experiment where their sleep was limited to five hours per night for one of the weeks (either the first or the second week of the study depending on the participant). During the other week, the participants slept normally.

As part of the experiment, participants were asked to look at 90 images from a standard collection of pictures used in psychology experiments. Each image in the collection is intended to elicit some type of emotional association, either positive, negative or neutral. Here, participants were asked to rate their emotional reactions to the pictures.

Whether or not people had their sleep limited, they tended to react to the negative images similarly negatively. However, there were differences in how they perceived the positive and neutral images. In particular, those who were on the five-hours-per-night sleep schedule gave more negative ratings to the positive and neutral images.

To put it another way, insufficient sleep apparently led the study participants to interpret images that weren’t inherently negative in a more negative way. The researchers found that this couldn’t be explained simply by the fact that sleep-deprived participants were in a bad mood to begin with, suggesting that disrupted sleep might give a more negative bias to how people interpret situations.

The authors of the study say, perhaps somewhat obviously, that their findings “have potential implications for daily life.”

I’ll spell those implications out: not getting enough sleep can mess with your emotions! You might find that after catching up on sleep, a situation that was bothering you before starts to look different and that your interpretation of it changes.