A baby's laughter -- reward for all those tears. Stockbyte/ Getty Images

Parents of newborn babies learn quickly there are many different ways for a baby to cry. One type of cry means the baby is hungry, another says the child needs to be changed and yet another may mean it simply wants some attention. Though these cries may seem indistinguishable to an outsider, parents learn to respond with exactly what their child needs.

Parents don't tend to put as much thought into what their child's laugh might mean, unless it's so diabolical that it clearly indicates an attack on another sibling. In fact, very few people think about differences in laughter at all.



According to expert Robert Provine, laughter is specifically a social structure, something that connects humans with one another in a profound way [source: Provine]. According to his findings, people are 30 percent more likely to laugh in a social setting that warrants it than when alone with humor-inducing media [source: Provine]. That means that you're more likely to laugh with friends while watching a comedy together than when you're watching the same show or movie by yourself.

Though there are many ways to laugh, from giggles to guffaws and from chuckles to cackles, it turns out that we humans laugh for many reasons, some of them odd. And it's more than just the latest David Sedaris book or episode of "Saturday Night Live" that has us doubled over -- 90 percent of our laughter has nothing to do with somebody telling a joke. [source: Trump].

So what are some of the different types and reasons for all the laughter?