Electrophysiological indexes of ToM and non-ToM humor in healthy adults

The cognitive processes involved in humor comprehension were analyzed by directly comparing the time course of brain activity associated with the perception of slapstick humor and that associated with the comprehension of humor requiring theory of mind (ToM). Four different comic strips (strips containing humorous scenes that required ToM, non-ToM humorous strips, non-humorous semantically coherent strips and non-humorous semantically incoherent strips) were presented to participants, while their EEG response was recorded. Results showed that both of the humorous comic strips and the semantically incongruent strip elicited an N400 effect, suggesting similar cognitive mechanisms underlying the processing of incongruent and humorous comic strips. The results also showed that the humorous ToM strips elicited a frontal late positive (LP) response, possibly reflecting the active deployment of ToM abilities such as perspective-taking and empathy that allow for the resolution and interpretation of apparently incongruent situations. In addition, the LP response was positively correlated with ratings of perceived amusement as well as individual empathy scores, suggesting that the increased LP response to ToM humorous strips reflects the combined activation of neural mechanisms involved in the experience of amusement and ToM abilities. Overall, humor comprehension appears to demand distinct cognitive steps such as the detection of incongruent semantic components, the construction of semantic coherence, and the appreciation of humoristic elements such as maladaptive emotional reactions. Our results show that the deployment of these distinct cognitive steps is at least partially dependent on individual empathic abilities.