男人平均每天多少次联想到性？It's a stat that gets bounced around as e-mail-forward wisdom: men think about sex every seven seconds.据一封被广为转发的电子邮件中的数据表明：男人每七秒钟就会想到性。 Even when the idea lacks this mythical specificity and grandiosity (that's 7,200 times a day!), the idea that men think about sex basically all the time is widespread. And so, it is possible to attach all kinds of bogus（伪造的） statistics to the feeling that men are sex-crazed pigs. But the actual number of times that men think about sex in a day is not clear-cut in scientific research. There is no perfect technology that taps into one's sexy brain waves. What researchers really do is come up with clever ways of asking people what they're thinking about. They call it "experience sampling." So, in a recent study, Ohio State University researchers gave people a clicker and were asked to hit one of three buttons on it--sex, food, sleep--every time the thought of one of those things came to mind. Their study showed that the average man had 19 thoughts about sex in a day. But the design of the study could have influenced the frequency count, writes cognitive scientist Tom Stafford in a new column. If you tell people to try to notice every time they think about something, you might very well increase the frequency of their thoughts about that thing. (Researchers call this the "white bear problem.") Other researchers--who use different sampling methods--get different results. So, a phone-based survey that asked participants more free-form questions seven times a day found that men think about sex less than they think about "food, sleep, personal hygiene（卫生）, social contact, time off, and (until about 5 p.m.) coffee." If you put these two studies together, as Stafford does, it's obvious that the technique influences, if not outright dominates, the phenomenon being studied. And yet the experience sampling method has gotten more popular, in part because everyone has a little computer in their hands all the time, which makes surveying much, much, much easier. "Smartphones are an ideal platform for conducting Experience Sampling Method (ESM) based studies," a recent review of sampling techniques found.
