Why does laughing feel so stinkin’ good?
Let the giggles move through you. (John Devolle/)The oldest known joke dates back nearly 4,000 years, and it’s a fart gag. The fact that we’ve been crackin’ wise for so long suggests there’s something innate about the need to laugh. Heck—chimps, rats, and perhaps even dolphins do it. Neuroscientists and psychologists aren’t sure about the exact evolutionary reason for a chuckle, though its ability to pep us up and promote bonding provide pretty solid clues. Whatever its underlying purpose, here’s how a good ol’ guffaw manifests in your body.When the frontal cortex [A]—an area responsible for decision-making—realizes something is funny, it starts a cascade of neurological responses.One signal hits the motor cortex [B]—which spurs the physical components of a giggle, including diaphragm contractions and head bobs—and then the periaqueductal gray [C], a chunk of nuclei in the brain stem that controls vocalization.Another command hits the amygdala [D], thalamus [E], and...