Sex on the Brain?

Summary

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Episode Overview

Podcast: More or Less (BBC Radio 4)
Episode: Sex on the Brain?
Air Date: June 10, 2013
Host: Tim Harford
Main Theme:
This episode of "More or Less" explores the statistics and myths surrounding human behavior—especially around sex, parenthood, and decision-making. Tim Harford and his guests scrutinize widely circulated “facts,” debunk urban legends (like “men think about sex every seven seconds”), and discuss how statistical thinking can reveal the truth behind everyday advice and anxiety.

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Key Discussion Points & Insights

1. The Power—and Pitfalls—of Parenting Advice

• Debunking Caffeine Fears in Pregnancy
  [01:02] Tim Harford brings up advice that expectant mothers should avoid caffeine. Charles Whelan, author of "Naked Statistics," challenges this:
  • Emily Oster’s book Expecting Better casts doubt on the caffeine-pregnancy link.
  • Statistical confusion: “It may... be healthy pregnancies causing people to drink less coffee rather than the other way around.” – Charles Whelan [01:20]
  • Studies suggest the correlation might be due to nauseous (and thus healthier) pregnant women avoiding coffee—not because caffeine is causing harm.

2. What Retailers Know About You

• Target's Pregnancy Prediction Algorithm
  [01:57] Whelan explains how US retailer Target used customer data to identify pregnant shoppers:
  • Customers register for baby items, revealing pregnancy.
  • Target tracked behaviors (e.g., more cotton balls, unscented lotion, vitamins) and developed a “pregnancy prediction” algorithm.
  • Famous anecdote: A father complains his daughter received baby-related coupons; it turns out she was indeed pregnant.
  • “It turns out his daughter was pregnant.” – Charles Whelan [03:21]

3. Does School Choice Matter As Much As We Think?

• Parental Worries About Schooling
  [03:24] Whelan reassures anxious parents that home background often outweighs school quality:
  • Children from educated, caring families “are probably going to be quite fine no matter what you do.”
  • Personal story: Despite his mother’s worry, Whelan sent his children to Chicago Public Schools, reasoning that most poor results stem from disadvantaged backgrounds—not from the schools themselves.
  • “They’ve turned out swimmingly.” – Charles Whelan [04:26]

4. The “Every Seven Seconds” Myth About Male Sexual Thought

• Tracing the Origins—and Truth—of a Popular Statistic
  [04:32] Harford investigates the claim that men think about sex every seven seconds.
  • Terry Fisher (Ohio State University): “Nobody has found a number that remotely resembles the [myth].” – [05:16]
  • If true, men would think about sex 8,229 times a day.

5. What the Data Shows: How Often Do People Think About Sex?

• Fisher’s Study: Real Numbers
  [05:46] Fisher recruited hundreds of US college students (men and women, 18-25), split into groups to record thoughts about sex, food, and sleep with “golf score” clickers:

  • Men:
    • Average: 34 sexual thoughts per day
    • Median: “A little less than 19” – Terry Fisher [06:46]
    • Range: 1 to 388 times per day
  • Women:
    • Average: “A little less than 19” thoughts/day
    • Median: Just under 10 – [07:35]
    • Range: 1 to 140 times per day
  • Men thought about sex about twice as often as women, and showed a much wider range.

• Memorable Quotes:

  • “If indeed it were true [that men think about sex every seven seconds], I’m really not sure how most men would get anything done.” – Terry Fisher [05:34]
  • “388 is quite a lot, but it’s well short of 8,229.” – Tim Harford [07:26]

6. Men vs. Women: Thoughts About Sex, Food, and Sleep

• General Trends
  [08:18] Both sexes thought about food and sleep frequently, with men overall reporting more thoughts (across all three domains) than women:
  • “Men were just reporting overall more of those thoughts than were the women.” – Terry Fisher [08:36]
  • The gender gap existed, but was a matter of frequency, not content.

7. A Playful Turn: Testing the Myth In-House

• The More or Less team was given clickers to record their own data—a light nod to replicating psychological research. (No results reported.)

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Notable Quotes & Moments

• On the seven-second sex myth:
  “I have no idea the origin of it, and yet it seems to appeal to people… If indeed it were true, I’m really not sure how most men would get anything done.”
  — Terry Fisher [05:16–05:34]
• On Target learning customers’ secrets:
  “It turns out his daughter was pregnant.”
  — Charles Whelan [03:21]
• On schools' impact:
  “As long as you’re a good, middle-class, caring parent … your children are probably going to be quite fine no matter what you do.”
  — Charles Whelan [03:41]
• On actual sexual thought frequency:
  “The median was a little bit less than 19 thoughts per day.”
  — Terry Fisher [06:46] “388 is quite a lot, but it’s well short of 8,229.”
  — Tim Harford [07:26]

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Important Timestamps

• [01:02] Caffeine and pregnancy—confusing causality
• [01:57] Target predicts pregnancies using buying behavior
• [03:24] School quality vs. parental influence
• [04:32] Debunking the “every seven seconds” sex thought myth
• [05:46] Fisher’s clicker study: real data about sexual thoughts
• [06:46] Statistics for male sexual thoughts: mean/median/range
• [07:35] Statistics for female sexual thoughts: mean/median/range
• [08:18] Comparing sex, food, and sleep thoughts by gender

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Summary

This episode uses wit and careful analysis to separate fact from fiction in sex statistics and everyday anxieties about parenting, data privacy, and education. Tim Harford and his guests reveal how easy it is for myths to take hold and how actual data can paint a much more reassuring and nuanced picture—whether the topic is caffeine for expectant mothers, extreme school competition, or how frequently sex crosses the mind. The tone is humorous, sceptical, and accessible, inviting listeners to think critically about the numbers that shape their lives.

Transcript

[A]

Thank you for downloading from the BBC. For details of our complete range of podcasts and our terms of use, go to bbcworldserveys.com podcasts. This is the short edition of More or Less, first broadcast on the BBC World Service. Hello and welcome to More or Less on the BBC World Service. We're your guide to the numbers that surround us in the news and in life. And I'm Tim Harford. Are you nervous about making big decisions? Well, don't be, because I have a large yet portable bag full of numbers to help you out. They come from a new book, Naked Statistics, which aims to show how statistics can be used to answer many of life's questions. I called up the author, Charles Whelan, and asked him whether he could serve as my statistical guide through parenthood. So let's start by examining one of those pieces of advice commonly given to expectant mothers. Try to avoid caffeine. What does the evidence say?

[B]

There's a new book by Emily Oster called Expecting Better that summarizes a lot of the data around healthy pregnancies. And she casts serious doubt on that particular piece of advice. And the reason is that the causality may go, in fact, the other direction. So we're taught to think that, well, caffeine may be bad for the baby, but in fact, one of the things we know is that nausea is a sign of healthy pregnancies. And of course, women who are nauseous are far less likely to drink coffee. So it stands to reason that it may, in fact be healthy pregnancies causing people to drink less coffee rather than the other way around.

[A]

Of course, it's not just what the numbers can tell us, but what the numbers can tell about us. If you use store cards, you probably know you're giving retailers quite a lot of information about yourself, but. But maybe more than you realize. Here's a tale about the aptly named U.S. department Store Target in the United States.

[B]

Maybe other places when you get pregnant, you're about to have a baby. Often there'll be a baby shower. People give you presents so you can register as you can for bridal registries for the particular presents that you like to get. And you can register at places like Target. Now, when you do that, what you are telling them is, I'm pregnant. Target took that information and cleverly began to look at the shopping habits of the women who had said they were pregnant. They bought more cotton balls. They switched to unscented lotions. They started buying certain kinds of vitamins. And then they made the Logical leap. Wow. If these pregnant women are doing those things, then other women also doing those things. And they came up with a pregnancy prediction indicator of 25 different behavioral changes. Well, the other women doing that must also be pregnant too. So they looked across all of their shoppers and made an inference about which ones are pregnant. Now, they could then send pregnancy related coupons to those women. We fast forward to a fellow in Minneapolis who was a father of a high school girl and he was not happy that his daughter was getting pregnancy related coupons in the mail for baby wipes and cribs and those kinds of things. So he called the store, complained loudly. The manager felt very bad. In fact, the manager felt so bad he actually called the guy back three days later to apologize again. At which point this father said, well, it's my turn to apologize. There have been some things going on in the house that I wasn't aware of. It turns out his daughter was pregnant.

[A]

And then what about that question which obsesses many parents from almost the moment their child is born? Where should we send them to school? Here, Charles Whelan says the numbers provide some comfort.

[B]

If you are indeed a good middle class parent as you describe yourself, then your children are probably going to be quite fine no matter what you do. So there's quite compelling evidence that just by virtue of being relatively well educated, caring parents of a certain means, you're going to speak a lot to your baby. You're going to do all the things that lead to a healthy, smart young child. One of the things that still has my mother lying on a couch with a cold compress on her head is that I send all three of my children to the Chicago public Schools and, and which may be notorious even around the world, but certainly in the United States are notorious for being some of the most strike ridden, gang prone and so on. And so I did make that decision because when I looked at the aggregate statistics for Chicago, what I realized is that most of the really most like 80% of the students were coming from low income, disadvantaged backgrounds. That wasn't my background. And I thought my kids would be fine. In fact, they've turned out swimmingly.

[A]

Charles Whelan, author of Naked Stripping the Dread from the Data this is more or less. And our email address for your comments and suggestions is more or [e-mail]. now, according to a popular folk statistic, men think about sex every seven seconds. But how do we know this, or indeed is it even remotely plausible? We decided to. Sorry, I was miles away. Yes, we decided to find out how often men really do think about sex. And so I spoke to Terry Fisher, professor of psychology at Ohio State University in the United States. I asked her, where does this statistic come from?

[C]

I've looked at all the research that I could find on this topic, and nobody has found a number that remotely resembles the. So I have no idea the origin of it, and yet it seems to appeal to people. You know, the fact that it's become a well known urban myth suggests that people think it's true and they think it's possible. If indeed it were true, I'm really not sure how most men would get anything done.

[A]

Now, how did. Sorry, I was a little distracted. Professor Fisher and a few of her students decided to do their own study. To test this idea, they recruited a few hundred college students, both men and women, aged between 18 and 25. They divided them into three groups and set them off with golf score counters. The first group had to click that little counter every time they thought about sex, the second to click when they thought about food, and the third when they thought about sleep. Obviously, American college students aren't particularly representative of the world population as a whole, but they might not be a bad place to start if you're launching a quick and dirty study into how often people think about sex. Now, I estimate that if you're awake for 16 hours a day and you think about sex every seven seconds, you think about sex 8,229 times a day. Well, I asked Professor Fisher how the men fared in her study.

[C]

The average number of thoughts about sex was 34 during the day. The median number, which is a statistic I actually prefer in this context because it eliminates the influence of outliers. The median was a little bit less than 19 thoughts per day.

[A]

So every hour or so.

[C]

That's correct.

[A]

And was there anybody who didn't think about sex at all or some sex monster who just thought about it constantly?

[C]

Well, we had quite a range, especially among the men. The average number of thoughts per day about sexuality ranged from 1 to 388.

[A]

So 388 is quite a lot, but it's well short of 8,229.

[C]

It certainly is.

[A]

Now, what about women? Were they very different?

[C]

Well, they were somewhat different. They had a more narrow range. So their thoughts ranged from one per day to 140 per day, with the average or mean number a little less than 19, the median just a little less than 10. And so they were reporting sexual thoughts about half as often as the men

[A]

did, but a huge range and 140 times a day. I mean, it's nothing like every seven seconds, but that's thinking about sex quite a lot. It sounds a bit like my wife, to be honest. But don't worry, I won't let her listen to this program. What about food? How often did men think about food? How often did women think about food or indeed, sleep? Was it similar to thinking about sex, or was it very different?

[C]

It was similar. It wasn't exactly the same. But in general, men were thinking about all of those things more than women. We analyzed the data. What we found was a significant gender difference, but not a difference in terms of type of thought. And so the men were just reporting overall more of those thoughts than were the women.

[A]

Professor Terry Fisher of Ohio State University. Well, we thought that this was an experiment worth replicating. So the More or Less production team has been supplied with golf counters and asked to record the frequency of their sexual thoughts. Here's a recording we made earlier. That's all we have time for this week. Our website is bbcworldservice.com More or less the place to read more or subscribe to our free downloads. If I can drag the team away from their golf clickers, we'll be back at the same time next week.