Fox on Sex: It's a Fact, Sex Makes Us Dumb

It’s a fact: Sex, or the prospect of having sex, makes you dumb. While the list of benefits goes on for miles (pain relief, more regular menstrual cycles, fewer colds, increase in youth-promoting hormone DHEA, etc.) the pursuit of sex makes you do stupid things.

Ask Tiger Woods or Jesse James, who in response to "What were you thinking . . . ?" will hang their heads, dog-that-got-caught-in-the-trash-like looks on their faces, and in private will bash their heads against the wall wondering, "What was I thinking? I wasn’t."

Otherwise perfectly sane people will put all their faith that the "other" (or others) will keep their secret and not turn into a psycho bunny boiler. And what do they have to lose? Everything: their family, their reputation, for some, their careers – all for a little bump and grind. Huh? And this happens over and over and over.

"There's very little advice in men's magazines, because men think, ‘I know what I'm doing.’ Just show me somebody naked." — Jerry Seinfeld

The division we joke about – the brain above and below the belt – holds true to a certain extent, especially for men since more of the male brain is designated for sex. In one of my favorite studies, Canadian researchers showed men pictures of conventionally pretty or not-so-pretty women. The men were told they could receive either $15 the following day or $75 after waiting a few days. The men who saw the picture of the beautiful women were more likely to take the $15, proving, researchers say, that men stop thinking about long-term consequences once the lust chemicals kick in. (The same test was done on women, and it had no effect on their thinking process). Some nice cleavage or legs can cause a man’s limbic system to fire up while his prefontal cortex heads south, leaving the judgment area of the brain not-so-well equipped.

Some ovulating women may be able to sympathize with men in feeling damn dumb, but only a few days out of the month: One study found fertile women more tolerant of one-liners. Another study of "sexual risk-taking behaviors" recorded that ovulating women found high-testosterone men more attractive; however, later in the month they considered more sensitive low-testosterone men to be better partners.

"Sex alleviates tension. Love causes it." — Woody Allen

"Sex Logic" is what I call the bizarre set of unsubstantiated rules that flit through – or dominate —your brain when you are faced with a flirtatious attractive other. Both men and women suffer from this affliction, which, unfortunately, can have far-reaching negative effects. In my opinion, men seem to be able to believe illogical things with unflinching faith (even though it is temporary); while women, on the other hand, it’s almost a cognitive decision to believe these things during the state of arousal, perhaps hoping they’ll be true.

Examples include:

— You are in a strip joint and you convince yourself that the stripper actually likes you. You leave the strip joint (alone), open your empty wallet and think, "Jeez, I am an idiot." A month later, you’ll do exactly the same thing again.

— You figure you don’t need to use a condom because you probably don’t have any more working sperm — because you’ve ridden a bike without padding, smoked too much marijuana, or are just too old. (And conversely, you’ll believe her when she says she’s pretty sure she can’t get pregnant due to some self-identified medical problem as well).

— You decide that a porn site looks legitimate enough to give your credit card information to (while the small print you are neglecting to read states that their billing cycle is every 15 days and you have to sign up for three months minimum).

In a woman, Sex Logic is the part of her brain that believes a man when he says things like, "I am almost divorced" or "That bump on my member is not an STD, it’s an ingrown hair."

"See, the problem is that God gives men a brain and a penis, and only enough blood to run one at a time." —Robin Williams

Sex Logic is dangerous; it leads to bad judgment. Men and women experience danger in different ways: Men don’t react until it’s imminent while women can look farther into the future. How this affects the cheating rates, and the getting-caught cheating rates is yet to be studied. However, the colloquial notion of "letting one out of the chamber" before going on a date may sound funny, but it’s a good idea. So is making big decisions under the influence of stupid, meaning when lust or the prospect of sex is in the air.

Dr. Belisa Vranich is a psychologist and sex expert. She is the author of three books, including her latest "He's Got Potential," which is in stores now. Do you have a "Dear Doc" question? E-mail Dr. Vranich at and check out her Web site at