Are you dating a night owl who loves to stay up late and wake up late in the morning?
Read this carefully as night owls, unlike early birds, are less likely to be in long-term relationships and have the same high propensity for risk-taking as men.
"Night owls, both males and females, are more likely to be single or in short-term romantic relationships versus long-term relationships when compared to early birds," said study author Dario Maestripieri, a professor in comparative human development at University of Chicago.
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In addition, male night owls reported twice as many sexual partners than male early birds, he added.
The link between the night-owl tendency and risky behaviour could have roots in evolutionary strategies for finding mates.
"From an evolutionary perspective, it has been suggested that the night-owl trait may have evolved to facilitate short-term mating, that is, sexual interactions that occur outside of committed, monogamous relationships," Maestripieri explained.
It is possible that, earlier in our evolutionary history, being active in the evening hours increased the opportunities to engage in social and mating activities, when adults were less burdened by work or child-rearing.
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The participants (110 males and 91 females) provided saliva samples to assess their levels of cortisol and testosterone.
The participants also described their own willingness to take risks and gave information about their sleep patterns.
Men had higher cortisol and testosterone levels than women.
But night-owl women had cortisol levels comparable to night-owl and early-morning men.
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The study suggests high cortisol levels may be one of the biological mechanisms explaining higher risk-taking in night owls.
According to Maestripieri, preferences for being a night owl or early morning person are due in part to biology and genetic inheritance, but also can be influenced by environmental factors such as shift work or child-rearing.
Gender differences in sleep patterns emerge after puberty and become weaker or disappear after women reach menopause, Maestripieri noted in the study.
The link between the night-owl tendency and risky behaviour could have roots in evolutionary strategies for finding mates, Maestripieri said in the study published in the journal Evolutionary Psychology.