A new study conducted by researchers at the University of Chicago suggests that sleep patterns are linked to character traits — and that night owls really do have a little more edge. Published in the journal Evolutionary Psychology, the study parsed sleep data gathered from more than 200 business-school students. Among the subjects, more men than women considered themselves night owls, and men got less sleep overall. The researchers also tested the subjects' saliva to collect data on levels of cortisol, a hormone widely associated with risk taking as well as arousability. Usually, females have lower amounts of the daredevil hormone than men. But, the study found that women who regularly stayed up late had levels of cortisol similar to those of the male subjects — much higher than the female early birds in the study. Further, survey questions on subjects' love lives revealed that night owls, both male and female, were less likely to be in a long-term relationship.
Although cortisol levels can sometimes be affected in the short term by stress, the study also measured changes in cortisol levels in response to reported stress. They found that stress cortisol responses were unrelated to sleep patterns — meaning that the study's authors could rule out stress as the reason cortisol levels rose.
Of course, this isn't to suggest that people are single because they go to bed too late. But, we think it's interesting to consider the way our biology shows up in our behavior. Turns out, night owls really are too cool for school. (ScienceDaily)