Neuroscience of sarcasm

We know sarcasm when we hear it. Usually, anyway. Certain kinds of brain injury or dementia can cause us to completely miss when someone is being sarcastic. To understand why, neuropsychologists at the University of California, San Francisco scanned the brains of a variety of people to find where our appreciation for sarcasm lies. From the New York Times:

…The magnetic resonance scans revealed that the part of the brain lost among those who failed to perceive sarcasm was not in the left hemisphere of the brain, which specializes in language and social interactions, but in a part of the right hemisphere previously identified as important only to detecting contextual background changes in visual tests.

"The right parahippocampal gyrus must be involved in detecting more than just visual context – it perceives social context as well," (lead investigator Dr. Katherine) Rankin said.

The discovery fits with an increasingly nuanced view of the right hemisphere's role, said Dr. Anjan Chatterjee, an associate professor in the Center for Cognitive Neuroscience at the University of Pennsylvania.< "The left hemisphere does language in the narrow sense, understanding of individual words and sentences," Dr. Chatterjee said. "But it's now thought that the appreciation of humor and language that is not literal, puns and jokes, requires the right hemisphere."