Brain activation during sight gags and language-dependent humor.

Humor is a hallmark of human discourse. People use it to relieve stress and to facilitate social bonding, as well as for pure enjoyment in the absence of any apparent adaptive value. Although recent studies have revealed that humor acts as an intrinsic reward, which explains why people actively seek to experience and create humor, few have addressed the cognitive aspects of humor. We used event-related functional magnetic resonance imaging to differentiate brain activity induced by the hedonic similarities and cognitive differences inherent in 2 kinds of humor: visual humor (sight gags) and language-based humor. Our findings indicate that the brain networks recruited during a humorous experience differ according to the type of humor being processed, with high-level visual areas activated during visual humor and classic language areas activated during language-dependent humor. Our results additionally highlight a common network activated by both types of humor that includes the amygdalar and midbrain regions, which presumably reflect the euphoric component of humor. Furthermore, we found that humor activates anterior cingulate cortex and frontoinsular cortex, 2 regions in the brain that are known to have phylogenetically recent neuronal circuitry. These results suggest that humor may have coevolved with another cognitive specialization of the great apes and humans: the ability to navigate through a shifting and complex social space.