"Women can be hilarious... but fewer of them bother trying because they don’t get the same rewards for it."

Says John Tierney. And by "rewards," he means sex. It's evolution talk, of course. You wouldn't "bother" to be funny just because you like to be amused. If you want to be amused and you're female, it's less trouble to dispense sexual favors and get some guy to go to the bother of being funny. That's the theory. I'm not giving advice, just rephrasing the theory.

IN THE COMMENTS: Galvanized makes a good point about aesthetics:

Women, in conversation, are very aware of being judged by their appearance and, thus, feel others find them most attractive when they are smiling and/or laughing and most at ease in being reactive. To be funny sometimes requires affectation of the expressions, voice and body that may not be physically flattering. God forbid! LOL Men, on the other hand, understand that their wit and intellect are socially valued -- the content they contribute in conversation -- and, thus, feel the need to draw attention (strut their stuff in a comedic way when their physique alone doesn't draw), and what better way to draw out a positive reaction than through humor? It's all part of the dance. Comedy is a beta male's best response to an alpha's dominance because, hey, they all gotta find a mate. In the end, we all know that women are just as entertaining, but many women simply feel that leaving the comfort zone and being funny compromises beauty and therefore opt in favor of being aesthetically pleasing rather than intellectually stimulating. Plus, like it says, we just don't have to because we're not usually the initiators and can sit back and watch. In short, women are taught early on (sadly) that funny is not pretty, comedy is not becoming, shtick is unflattering, and also to wait to be approached and hope to be noticed. To court reactions with humor seems to be doing the male's job.

Some, however, do feel secure enough in their looks and risk it or just don't care and buck the system. I do believe, however, that it's innate behavior of the sexes, with some exceptions, thank God. Many women will always be overly conscious of their appearance because our instincts tell us that beauty draws, as many men will always believe that they are socially superior because that arrogance assists them being the initiators. But, again, I appreciate the exceptions to the theory.

She's speaking in terms of learned behavior, but I assume you could present easy laughter as something that would be selected for in evolution.