We all have heard the studies done that say women's brains are set up more for language and men for action. This might be true to some extent, but I know a lot of men who are talkative, more so than some women.
If we go back to caveman days, we would see the females of the group staying near the camp with the children and the old of the tribes, gathering berries and other items. Men would have been out on the hunt. Women may have done more socializing communication, but men would have had to communicate on strategies for the hunt.
This is where I think our language skills started to separate. Men use their language to get things done. Women use their language to pass the time and get things done. Women had more time to sit around with other females of the group and chat over sewing hides, cleaning berries, making things...at least when we started making things like baskets, pottery, and small tools.
Fast forward to modern times: Women do a lot of socializing, but so do men. I see more women use laughter as a way to cover up insecurities, or nervousness. It is not the same as laughing in merriment. Men on the other hand when with other men, brag, jest, use aggression, but also laugh merrily.
Look at comedians for example. The funniest ones are usually men. Guys like Robin Williams, Adam Sandler, and Chris Rock are very funny men. I watched behind the scenes parts on DVD's like RV with Robin Williams, and he does nothing on set but make people laugh, and he himself laughs a lot.
Laughter is the human's way to bond with one another. Since women do spend a good amount of time socializing; we may over the course of a day, laugh more times then our husbands. However to use a blanket statement that women laugh more than men is just silly. Unfortunately statistics done on this sort of thing is a small survey of at most 2000 people; this can not be applied to the whole of society. Each person is different.
Watching my own children, I see my son laugh way more often than my daughter laughs. He finds great amounts of amusement in his own body functions. He can be sitting quietly coloring a picture and all of a sudden a gas bubble erupts from his back side. This is send him into a laughing fit for at least five minutes, especially if someone notices his gassiness.
What makes the sexes laugh is usually different. Women laugh more at irony, wittiness, and social observations. Men will laugh at armpit farts, a friend falling over, crazy voices and impressions, and other things that might seem simple to a woman. But is the value of their laughter any less than a woman's? Definitely not! Men use laughter with each other the same way women do with their female friends; men just find different things funny.
Personally I tend to be in the middle. I can chat and laugh with other women over social things and observations; but I can also laugh at The Three Stooges and slapstick comedy that men love. I don't think it is true that men laugh less than women; I think they just laugh differently than we do.