How do extraverts process jokes? An event-related potential study on humor processing

Extraverts and introverts show different preferences for humor regarding different humor types. However, few studies focused on the neurological underpinnings of the connection between extraversion and the stage-wise cognitive model of humor processing. To investigate the influence of extraversion on different sub-stages of humor processing, electroencephalography (EEG) data was collected when participants read and rated jokes and non-jokes. The event-related potential (ERP) data showed a smaller N400 (300-500 ms) but a larger late positive potential (500-900 ms) for jokes than non-jokes, which may reflect lexical association and integrative interpretation in joke processing. The more extraverted group had a larger P2 (200-300 ms) and a smaller N400 than the less extraverted group in response to all the stimuli, which may indicate their different allocation of attentional and cognitive resources to external stimulation. Additionally, the regression analyses showed that the late positivity effects of jokes were positively correlated with the extraversion level. The results could imply extraverts' controlled processes of cognitive resource allocation for jokes, and suggest the same groups' attentiveness and motivation for reward stimuli (i.e., jokes). Importantly, our ERP data could support extraverts' increased exploration for verbal humor from a better temporal aspect for the first time.