男人每隔多久就會“性”趣盎然？

It's a stat that gets bounced around as e-mail-forward wisdom: men think about sex every seven seconds. 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 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, 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.

But it's difficult to judge a person's thoughts, no matter what technology people use. The lead researcher in the Ohio State study, Terri Fisher, provided a self-critique of her study, which applies to many of them.

"We weren't able to study how long the thoughts lasted or the nature of the thoughts. We also don't know if all of our participants followed the instructions and really clicked every time they had the sort of thought that they were supposed to track," Fisher wrote. "However, even if they didn't, the fact that they were supposed to be clicking probably made them more aware of their thoughts about their assigned topic than they might otherwise have been, and that would have been reflected in their daily reports."

The perfect technology would directly measure one's brain activity and somehow translate that into the number of sexual thoughts one had, but even that might prove very difficult. What we call "a thought" is not the discrete thing that we like to pretend. "There’s also the tricky issue that thoughts have no natural unit of measurement," Stafford writes. "Thoughts aren’t like distances we can measure in centimetres, metres and kilometres. So what constitutes a thought, anyway? How big does it need to be to count? Have you had none, one or many while reading this?"

Perhaps the more interesting question is why we want to quantify this kind of thing at all. Does it matter if men think of sex—however defined—12 times a day, or 19, or 7, or 400?

These numbers reduce a whole set of arguments about the relative sexualities and norms of men and women, detaching the feelings from the lived experience of people.

That may be useful rhetoric for proving that men are pigs or women should be chaste or whatever, but the data says more about the limitations of our survey technologies than the nature of human sexuality.據一封被廣爲轉發的電子郵件中的數據表明：男人每七秒鐘就會想到性。雖然這種說法缺乏根據且過於誇張（那可是一天7200次！），但還是廣爲流傳。看來“男人就是種豬”這種說法完全有可能被添油加醋地附上各種不靠譜的數據。

但科學研究還沒有就男人每天產生“性”趣的次數提出一個明確的答案。還沒有技術能夠監測到“人腦性電波”。

但研究人員想到了一個聰明的點子，就是問人們他們在想什麼。研究人員將這種方法稱之爲“體驗抽樣”。在最近的一項研究中，俄亥俄州立大學的研究人員發給受訪者一個點擊器，上面有三個按鈕，分別代表性、食物、睡眠，受訪者被要求每當想到其中之一時便按下相應的按鈕。該研究結果顯示男人平均每天聯想到性的次數是19次。

但認知學專家湯姆·斯塔福德（Tom Stafford）在一期新專欄中寫道，這種研究方法的設計原理也許影響了頻率的計數結果。如果你讓別人在想到某事時試着去記錄的話，那麼你很可能會提高他想到那件事的頻率。（科研人員稱之爲“白熊效應”，其得名於1978年心理學上著名的“白熊試驗”，即，對於事情，你越想忘記，反而記得的越清楚。）

其他研究者採用不同的抽樣方法得出了不同的結果。他們採用電話調查的方式，每天七次向受訪者問一些寬泛的問題。研究人員發現男人想到性的次數低於想到“食物、睡眠、個人衛生、社交、休假、咖啡（下午五點左右）”的次數。

如果你像斯塔福德一樣把這兩個研究綜合起來看，你就會發現科技會影響男人想到性的次數，雖然不是百分百的影響。

然而“體驗抽樣”這一研究方法卻越來越流行。部分原因是因爲現如今人手一部手機使得調查要比過去方便得多。最近一項對抽樣技術的研究表明：“智能手機是進行‘體驗抽樣’的絕佳平臺。”

但不管人們使用什麼技術，都很難去判定一個人的想法。俄亥俄州立大學研究項目的帶頭人特芮·費舍爾就對自己的研究做了自我檢討，這些批評同樣適用於其他的研究項目。

費舍爾寫道：“我們沒研究出想法持續的時長或其本質是什麼。我們也不知道這些受訪者是否遵從指示在每一次想到相應事物的時候都會按下按鈕。但是，即使他們沒有每次都按，‘要按按鈕’這個念頭也許會讓他們比平時更加在意實驗中提到的主題，而這或許就反映在他們每天的反饋數據中。”

完美的技術或許能夠直接監測腦部活動並通過某種方式記錄下有關性的想法的次數，但即使這樣也被證明是很難實現的。所謂“一個想法”並非是我們可以假裝出來的一個孤立的東西。斯塔福德寫道：“比較棘手的是，想法並不能用單位來度量。它不像距離可以用釐米、米和公里來丈量。所以，到底是什麼構成了一個想法？多大的想法才能被算作是一個想法？當你讀到這段話的時候，你是毫無想法呢，還是有一個甚至許多想法？”

也許，我們爲什麼想把男人的“性”趣量化纔是個更有意思的問題。不管是每天12次、19次、7次還是400次，男人想到性的次數的多少——無論哪種算法——又有什麼意義呢？

這些研究結果得出的數字減少了關於相對性徵和男女標準的各種爭論，打破了人們生活中“男人就是種豬”的固有認知。

也許從修辭手法來說，以上結論可以證明“男人是豬”或女人應該保持純潔，不過這些研究數據更多地體現了我們的調查技術的侷限性，而非人類性活動的本質。