Researchers have found that vulnerability to sleep deprivation is influenced by the interaction between waking social activity and individual personality traits.
Results of a new study, which appears in the November 1 issue of the journal SLEEP, show that extraverts who were exposed to 12 hours of social interaction were more vulnerable to subsequent sleep deprivation than those who were exposed to an identical period of isolated activity. Speed on the Psychomotor Vigilance Task (PVT) for extraverts in the socially enriched group was significantly slower at 4 AM, 6 AM, and noon compared with speed for extraverts in the socially impoverished condition. Introverts’ speed on the PVT was relatively unaffected by prior social exposure.
"Extraverts exposed to socially enriched environments showed greater vulnerability to subsequent sleep deprivation than did extraverts exposed to an identical but socially impoverished environment," said principal investigator and lead author Tracy L. Rupp, PhD, research psychologist in the Behavioral Biology Branch of the Center for Military Psychiatry and Neuroscience at Walter Reed Army Institute of Research in Silver Spring, Md. "The ability of introverts to resist sleep loss was relatively unaffected by the social environment. Overall, the present results might also be interpreted more generally to suggest that waking experiences, along with their interaction with individual characteristics, influence vulnerability to subsequent sleep loss."
According to the authors, social interactions are cognitively complex experiences that may lead to rapid fatigue in brain regions that regulate attention and alertness. Therefore, high levels of social stimulation may be associated with an increase in the need for sleep. However, some individuals have a trait-like resistance to sleep loss that appears to be rooted in genetic differences. In particular, introverts may have higher levels of cortical arousal, giving them greater resistance to sleep deprivation.
Rupp noted that the results may have implications for industries that require workers to maintain alertness during periods of sustained wakefulness. Potential performance consequences resulting from team assignments or independent work may vary depending on an individual’s personality traits.