A recent study from Uppsala University shows that young adults who are sleep-deprived judge anger as less trustworthy and healthier-looking. In addition, neutral and scared faces look less attractive after the loss of sleep. The results have been published in the journal of scientific research Nature and Science of Sleep.
Utilizing eye-tracking, a technology that is able to detect what people are looking at in real-time researchers of Uppsala University in Sweden performed an experiment on 45 females and males to study how sleep loss can affect the way that humans look at and assess happy, fearful angry, neutral and threatening faces. The participants slept for one night without sleeping at all, and the other night that included an eight-hour sleeping time. The eye movements of the participants were recorded at the beginning of each morning after both night’s sleep.
“When sleep-deprived, our research subjects spent less time fixating on faces. Since facial expressions are crucial to understanding the emotional state of others, spending less time fixating on faces after acute sleep loss may increase the risk that you interpret the emotional state of others inaccurately or too late,” states Lieve van Egmond. Van Egmond is the first researcher and doctoral student at the Department of Surgical Sciences at Uppsala University.
“The finding that sleep-deprived subjects in our experiment rated angry faces as less trustworthy and healthy-looking and neutral and fearful faces as less attractive indicates that sleep loss is associated with more negative social impressions of others. This could result in less motivation to interact socially,” says the senior writer Christian Benedict, Associate Professor of Neuroscience.
“Our participants were young adults. Thus, we do not know whether our results are generalisable to other age groups. Moreover, we do not know if similar results would be seen among those suffering from chronic sleep loss,” says Lieve van Egmond.