While sleep deprivation really messes with mood, a new study in PlosOne shows it does not interfere with their ability to evaluate emotional situations.
Researchers found that, contrary to the assumption that feeling more negative affects people’s experiences of their environment, 24 hours without sleep did not affect participants’ ability to process emotional words and images.
“People do become less happy through sleep deprivation, but it’s not affecting how they are processing emotional stimuli in their environment,” said lead author Anthony Stenson, WSU psychology doctoral student.
The researchers found that sleep deprivation does not numb people to emotional situations, but it reduces their ability to control their own emotional responses, with implications for healthcare workers and other professions who must deal with sleep loss.
For the study, about 60 adult participants spent four consecutive days in a sleep centre at the WSU Elson S. Floyd College of Medicine. They were allowed to sleep normally the first night and then given a set of baseline tests to judge their mood as well as their emotional regulation and processing ability. Then, they were divided into one group of 40 people staying awake the second night, and a control group of 20 allowed a normal sleep period. The tests were then re-administered at different intervals.
The emotional regulation and processing tests both involved viewing a series of images with positive and negative emotional connotations. In the emotional regulation tests, participants were given a prompt to help them recontextualise negative images before seeing them and asked to control their feelings. The sleep-deprived group had greater difficulty reducing the emotion they felt when instructed to do so.
The processing tests involved responding to words and images with emotional content, for example rating the emotions conveyed by a smiling family, a growling dog or a crying child. All participants performed similarly on these tests whether they were sleep deprived or not.
The ability to process emotional content and the ability to control one’s emotions are distinct and important, especially for some professions, said co-author Paul Whitney, a WSU professor of psychology.
“I don’t think we want our first responders being numb to the emotional nature of the situations they encounter, and it looks like they are not,” he said. “On the other hand, reacting normally to emotional situations, but not being able to control your own emotions, could be one reason sleep loss sometimes produces catastrophic errors in stressful situations.”
Previous studies have largely focused on the impacts of sleep deprivation on ‘cold’ cognitive tasks, which are supposedly emotionally neutral tasks like recalling facts. These studies have also found that regulation, considered a ‘top-down’ cognitive process, is a major problem with cold cognitive tasks. Mental flexibility, for example, is compromised by sleep deprivation, an ability emergency room doctors use in dealing with unexpected situations.
The current study shows that top-down regulation is a problem as well with ‘hot’ or emotional cognitive processes. Future research is needed to understand whether the effects of sleep loss on the two top-down processes are linked.
Source: Washington State University
