Unlike lunch or dinner, there's no set time for getting it on. We can, essentially, do it anytime, anywhere, with anyone (with consent, of course), yet most of us have sex at night. It's not that we're necessarily hornier in the evening, but we've certainly been conditioned to be. Two not-so-recent studies, which have been analyzed and prodded over in the past couple months, show we've learned to nurture our sexual nature.
The first study comes from 1982, when three researchers evaluated the sexual lives of 78 young, married people over the course of one year. On the whole, researchers found that sexual activity spikes during the weekend. They then got down to the nitty-gritty: They analyzed the subjects' daily rhythms and found a 58-percent spike of action in the evening and a slight resurgence in the morning hours around 6 a.m. Nothing like a good round of bedroom wrestling to start the day off, eh? A second study, done in 2005 by Roberto Refinetti, expanded on the 1982 study by increasing the age spectrum of its subjects and introducing possible environmental variables. What Refinetti found paralleled the findings of the earlier study and questioned the possible relation to societal standards of what is sleep-time and what is awake-time.
Biologically, our hormones don't have timers that go off, alerting us when it's sexy-time. Hormones affect our overall interest in sex, but we've somehow separated them from bodily urge (the desire to do it right now). What Refinetti's study highlights is our ability to control urges. Just because we can have sex anytime and anywhere doesn't mean we bone in the middle of the office — generally! We've learned to suppress our natural tendencies until the opportune time comes along, which, in most cases, is at night, in bed, with our partner. Convenience becomes a motivating factor.
Refinetti followed his 2005 study with a shorter one, asking subjects why they had sex when they did. Most of the answers boiled down to convenience: Their partner was available, they were already in bed, or their daily schedule won't allow for an afternoon delight, etc. If we really, really wanted to figure out our natural sexual tendencies, we'd have to put couples alone in a dark room for days, so they could have sex anytime — but who has time for a study like that? (io9)