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Are Night Time Guys the Right Time Guys?

A study sheds light on whether Night Owl men are more sexually competitive.

You have to feel for Night Owls. Known for their emotional instability, troubled relationships with family and friends and comparatively “dark personalities,” they don't exactly have the best of reputations. By contrast, Early Birds are typically seen as emotionally stable, conscientious, and trustworthy.

But are evening people more sexually competitive than morning people?

According to research, men who are Night Owls, in particular have more short-term mating success, which is measured by the number sexual partners over one's lifetime. Curiously, men are overrepresented among evening-types, while more women make up morning-types. This sex difference in chronotype, i.e., morning vs. evening disposition, is negligible before puberty and after menopause. Thus, it might also be what's called a sexually dimorphic trait, which are traits that show a sex difference when they emerge at puberty. Think of larger breasts in women, and facial hair in men.

Sexually dimorphic traits are also related to mating and evolved by sexual selection. This simply means that over the course of evolution, sexual selection operated on sexually dimorphic traits, and in so doing increased the reproductive success of individuals. So the upshot is this: Since "eveningness" in males becomes more pronounced in males than females at puberty, it may be a characteristic related to mating and reproductive success in men.

A recent study led by Davide Ponzi of the University of Chicago investigated the relationship between chronotype and mating. Specifically, the researchers predicted that eveningness would be associated with greater sexual competitiveness, as measured by scores on the Intrasexual Competition Scale. This questionnaire assesses an individual's “views of a competitive confrontation with an individual of the same sex in the mating context.” Sample items include "I can’t stand it when I meet another man who is more attractive than I am," and "I always want to beat other men."

Here's what the investigators did. They recruited straight males at the University of Chicago — the final sample was comprised of 107 men, of which the average age was 22.44 years. In addition to the Intrasexual Competition Scale, they had them complete a questionnaire assessing morningness vs. eveningness and personality traits (specifically “The Big Five,” which are the dimensions of openness, conscientiousness, extraversion, agreeableness, and neuroticism). Then they crunched the numbers.

What did the researchers find? As expected, evening-type men showed significantly higher levels of sexual competitiveness than morning-types. They may see other men as possible threats to their mating success, and may be more confrontational toward their rivals. Moreover, morning-types were slightly higher on the personality dimensions of agreeableness and conscientiousness. Similarly, men who scored higher on sexual competitiveness also showed significantly lower levels of agreeableness and conscientiousness.

The findings of this study remain in keeping with research efforts demonstrating that eveningness is significantly associated with behaviors and traits that facilitate reproductive success, such as short-term mating, greater sexual partners (particularly in men,) positive attitudes toward promiscuity, Machiavellianism, impulsiveness and sensation-seeking.

What can we learn from this body of work? At the very least, the differences between morning and evening people are far greater than the time they go to bed.

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Vinita Mehta, Ph.D. is a licensed Clinical Psychologist in Washington, D.C., and an expert on relationships, managing anxiety and stress, and building health andresilience. Dr. Mehta provides speaking engagements for your organization andpsychotherapy for adults. She has successfully worked with individuals struggling with depression, anxiety, and life transitions, with a growing specialization in recovery from trauma and abuse. She is also the author of the forthcoming book on dating, mating, and relationships.