According to a recent study led by Postdoctoral Fellow Ivan Vargas, PhD, in the journal Cognitive Therapy and Research, those who are sleep deprived lose some of their ability to be positive-minded people, reports Penn Medicine News.

“In general, we have a tendency to notice positive stimuli in our environment,” said Vargas. “We tend to focus on positive things more than anything else, but now we’re seeing that sleep deprivation may reverse that bias.”