Using this method they found that the average man in their study had 19 thoughts about sex a day. This was more than the women in their study – who had about 10 thoughts a day. However, the men also had more thoughts about food and sleep, suggesting perhaps that men are more prone to indulgent impulses in general. Or they are more likely to decide to count any vague feeling as a thought. Or some combination of both.

The interesting thing about the study was the large variation in number of thoughts. Some people said they thought about sex only once per day, whereas the top respondent recorded 388 clicks, which is a sexual thought about every two minutes.

However, the big confounding factor with this study is "ironic processes", more commonly known as the "white bear problem". If you want to have cruel fun with a child tell them to put their hand in their air and only put it down when they've stopped thinking about a white bear. Once you start thinking about something, trying to forget it just brings it back to mind.

This is exactly the circumstances the participants in Fisher's study found themselves in. They were given a clicker by the researchers and asked to record when they thought about sex (or food or sleep). Imagine them walking away from the psychology department, holding the clicker in their hand, trying hard not to think about sex all the time, yet also trying hard to remember to press the clicker every time they did think about it. My bet is that the poor man who clicked 388 times was as much a victim of the experimental design as he was of his impulses.

Always on my mind



Another approach, used by Wilhelm Hoffman and colleagues, involved issuing German adult volunteers with smartphones, which were set to notify them seven times a day at random intervals for a week. They were asked to record what featured in their most recent thoughts when they received the random alert, the idea being that putting the responsibility for remembering onto a device left participants' minds more free to wander.

The results aren't directly comparable to the Fisher study, as the most anyone could record thinking about sex was seven times a day. But what is clear is that people thought about it far less often than the seven-second myth suggests. They recorded a sexual thought in the last half hour on approximately 4% of occasions, which works out as about once per day, compared with 19 reported in the Fisher study.

The real shock from Hoffman's study is the relative unimportance of sex in the participants' thoughts. People said they thought more about food, sleep, personal hygiene, social contact, time off, and (until about 5pm) coffee. Watching TV, checking email and other forms of media use also won out over sex for the entire day. In fact, sex only became a predominant thought towards the end of the day (around midnight), and even then it was firmly in second place, behind sleep.