The role of the amygdala in incongruity resolution: the case of humor comprehension

A dominant theory of humor comprehension suggests that people understand humor by first perceiving some incongruity in an expression and then resolving it. This is called "the incongruity-resolution theory." Experimental studies have investigated the neural basis of humor comprehension, and multiple neural substrates have been proposed; however, the specific substrate for incongruity resolution is still unknown. The reason may be that the resolution phase, despite its importance in humor comprehension, has not been successfully distinguished from the perception phase because both phases occur almost simultaneously. To reveal the substrate, we conducted a functional magnetic resonance study using 51 healthy participants. We used a humor-producing frame of "Given A, I'd say B, because C" so as to focus on the resolution phase independently by suspending humor processing just after the perception phase. This frame allowed us to separate the two phases. Based on our results, incongruity resolution evoked positive emotion and activated the left amygdala, which is known to be related to positive emotion. On the basis of these findings, we argue that the amygdala plays an important role in humor comprehension, considering its functional role in emotional evaluation, particularly the relevance detection for incoming stimuli.