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One of the traits that tops many women’s must-haves in a partner is a . But, of course, almost everyone has a sense of humor: it’s really the type of humor we make and appreciate that separates us.

Some people like observational comedy, others split their sides for slapstick comedy, and surreal comedy can have an audience rolling in the aisles. But one really basic aspect of comedy is how clean or dirty it is. Many of us couldn’t care less how often a comic swears or whether they touch on taboo topics. However, this kind of humor isn’t for everybody, and even those who might enjoy a set by famously obscene comedians Lenny Bruce or Frankie Boyle wouldn’t want to hear the same gags over a candlelit meal on a first date.

Mary Medlin and her colleagues from the University of Southern Mississippi, in research published recently in the journal and Individual Differences, sought to find out whether women prefer men who crack dirty or clean jokes. They searched the web for examples of clean and dirty humor (isn’t science great?) and had 100 men and women rate the dirtiness and funniness of 50 jokes. Using these ratings, they picked four dirty and four clean jokes that were about equally funny.

Next, the psychologists had 100 women look through some men’s profiles. Of course, the profiles were fake: Each one included one of the clean or dirty jokes and a photo of some random dude. The women rated each man for his as a long-term partner — someone they could imagine marrying — and a short-term partner , or someone who might be attractive for a fling.

Clean humorists were more attractive for both long- and short-term relationships, but the difference between dirty and clean humorists was most pronounced when women judged for a long-term relationship. To put it another way, women were more willing to tolerate a filthy joke from a man when judging his attractiveness as a short-term hook-up.

In a follow-up study of 150 new volunteers, Medlin was able to replicate this finding. What’s more, she also had the women complete the Sociosexual Orientation Index. Frequent readers of this blog will know that the SOI is the survey that measures a person’s desire for uncommitted , as well as their attitude toward it (whether it’s right or wrong), and their actual short-term sexual behavior.

Medlin found that women who held a positive attitude toward casual sex tended to find dirty jokes funnier.

It’s likely that men (and women) deploy dirty humor for a number of reasons, but one reason why men might tell a dirty gag in a dating context is because it “sexualizes” the interaction: A woman who is fine with this might laugh along to signal her continued interest. A shared appreciation of dirty humor might also be a way for two potential partners to signal that they are both interested in a fling.

However, men should be reminded that women generally preferred clean humor in a man, both for a casual hook-up and for something longer-term. The best strategy is to leave the knob gags to the professionals.

Bad jokes

Now, at this point I’m sure you’re wondering why I haven’t quoted any of the jokes used in Medlin’s study. OK, here they come. But be warned: They’re bad. I’ve read quite a few academic papers about the psychology of humor over the past decade and the jokes are always abysmal. Just teeth-grindingly terrible. These are no exception. First, a clean joke.

I once gave my husband the silent treatment for an entire week, at the end of which he declared, “Hey, we’re getting along pretty great lately!”

And now a dirty joke:

Two drunks were sitting at the bar, staring into their drinks. One said: ‘Hey, you ever seen an ice cube with a hole in it before?’ The other said: ‘Sure. I’ve been married to one for eighteen years.’

The first thing you might notice about these jokes, apart from the fact that they’re about as funny as a tax form, is that they are pretty sexist. Some of the other jokes are just as bad, and I think that the clean jokes used by Medlin are even worse in this respect than the dirty jokes. This raises the possibility that the findings of Medlin’s studies might have been stronger, weaker, or completely non-existent if she had chosen different gags.

We’ll have to await the results of future, more varied studies to find out if the joke’s on us.