Q. Aren't laughter and a sense of humor pretty much one and the same?
A. According to Webster's Dictionary humor is a mental faculty, the ability to discover, perceive, effectively express, or appreciate the ludicrous, the comical, or the absurdly incongruous.
Laughter is a sound; the expression of mirth, joy, or scorn through a chuckle or explosive noise. A form of audible speech, laughter may come from Broca's Area (audible speech) in the left frontal lobe.
While closely connected, laughter and humor are not synonyms. They represent two different concepts, with each cerebral hemisphere contributing specialized functions.
The functions necessary to develop a sense of humor appear to be centered in the right frontal lobe. This part of the brain is alert to subtleties, nuances, and pulls all the threads together (e.g., context, assumptions, knowledge of personal prejudice) in order to "get" the joke including meaning. As Rita Carter put it in Mapping the Mind, seeing a nice-looking person slip on a banana peel may not be very funny, but watching a pompous bully come a cropper, is!
The left hemisphere understands the actual words and appears to be attracted by wordplay. It tends to be very literal in developing an interpretation of a joke. It is also responsible for the sense of amusement and can trigger laughter when something prompts it to do so.
Having said that, a fully rounded sense of humor requires the combined effort of both hemispheres. The left hemisphere alone likely would not make the instant connection between the twins and the punch line in this joke:
A girl goes on a blind date with Siamese twins. Next morning her mother asks, "Did you have a good time, honey?" The girl replied, "Ah, yes and no."
When asking this type of question, many brains would expect an either-or response: Yes, or No. To receive both would likely be unexpected. Such an answer might trigger a sense of humor in some brains.
While not every person develops a keen sense of humor, almost everyone can choose to laugh-although not everyone does. Some people have been heard to say, "I have a good sense of humor but I don't laugh very often." That's too bad because laughter can help to strengthen our immune system and age-proof our brain! It's a bit like changing a baby's diaper. It may not permanently solve any problems, but it makes things much more acceptable for a while!