The after-hours mutants

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Every night owl you meet will tell you the same thing: there is something magical about those late night hours when the rest of the world is sleeping. It's your time, unscheduled and undisturbed, to spend as you wish. To some, this perspective may seem lazy and immature, a luxury afforded only to those who don't have real adult responsibilities. And this may be partially true - many would-be night owls have few opportunities to enjoy the later evening hours because of work, kids, and other demands. But new research suggests that even these non-practicing night owls may be hard-wired to want to stay up late. Though sleep preferences are due in part to non-biological factors like culture, and family environment, at least 50% of the variance seems to be driven by genes, specifically something called the "after-hours mutant" which appears to prolong the circadian rhythm. As a result, evening people may find the traditional work schedule a constant battle with the snooze button, regardless of how much sleep they get.

Harvard Business Review: July-August 2010

You probably already know whether you're a morning or evening person, but if you're not sure, here are two ways to figure it out:

1) On weekends, or when you don't have to wake up at any particular time, when do you naturally wake up? If the answer is more than an hour or so different from when you wake up on weekdays, chances are you're an evening person by nature. Morning people tend to wake up just as early on weekends as they do during the week.

2) Regardless of how much sleep you've gotten, when do you find that you have the most energy? If your energy peaks in the morning and dwindles by late afternoon, you're a morning person. If it peaks later in the evening - you guessed it - you're an evening person.

The debate over whether it's better to be a night owl or an early bird has been going on for centuries, and more often than not the early birds have indeed gotten the worm, as their natural sleep schedule corresponds with traditional business hours. The stereotypical morning person arrive at the office chipper and energized, while the evening person stumbles in, coffee in hand, and stares at the computer screen for an hour before getting to work.

Research on the advantages and disadvantages of each "chronotype" has yielded mixed results, in part because it is difficult to conduct this research experimentally, making it hard to disentangle causes from consequences and to rule out mediating variables. Furthermore, the costs of being an evening person may result more from the difficulty of conforming to normal work hours, and to consequent sleep deprivation, than to anything inherent in preferring evening hours. Still, this line of research has produced some interesting findings. For example, night owls appear to be more intelligent and creative, on average, while morning people get better grades and have greater career success. Early birds may get a rush of adrenaline in the morning, but they suffer in the afternoon and evening, when they are more prone to cognitive failures. Night owls, on the other hand, are often able to concentrate long into the evening, even if they've been awake for just as long. Evolutionary psychologists have suggested that a preference for late hours may suggest a higher level of intelligence because being a night owl is presumably an evolutionary novel preference, though this hypothesis is controversial. Evening people also love to mention that President Obama is a night owl. But he also probably gets under 6 hours of sleep a night, something that most of us can't sustain. 

Whether you are a morning or an evening type, the best approach seems to be to find a way to maximize the strengths of your style (without losing too much sleep as a result), and to respect preferences that differ from your own. For example, policy makers are beginning to realize that high school students, who tend to be natural night owls for developmental reasons, should not be forced to wake up at the crack of dawn. Academics have long accommodated later sleep cycles, especially in certain fields (it's rare for a psychology class to start before 10am), but the rest of the working world has yet to catch up. 

Godinho, S., Maywood, E., Shaw, L., Tucci, V., Barnard, A., Busino, L., Pagano, M., Kendall, R., Quwailid, M., Romero, M., O'Neill, J., Chesham, J., Brooker, D., Lalanne, Z., Hastings, M., & Nolan, P. (2007). The After-Hours Mutant Reveals a Role for Fbxl3 in Determining Mammalian Circadian Period Science, 316 (5826), 897-900 DOI: 10.1126/science.1141138

Kanazawa, S., & Perina, K. (2009). Why night owls are more intelligent Personality and Individual Differences, 47 (7), 685-690 DOI: 10.1016/j.paid.2009.05.021