Mapping the "Funny Bone": Neuroanatomical Correlates of Humor Creativity in Professional Comedians

Association between cortical thickness or surface area and divergent thinking in patients with bipolar disorder

OBJECTIVE

Divergent thinking is a critical creative cognitive process. Its neural mechanisms have been well-studied through structural and functional imaging in healthy individuals but are less explored in patients with bipolar disorder (BD). Because of the traditional link between creativity and BD, this study investigated the structural correlates of divergent thinking in patients with BD through surface-based morphometry.

METHODS

Fifty-nine patients diagnosed with BD I or BD II (35.3 ± 8.5 years) and 56 age- and sex-matched controls (33.9 ± 7.4 years) were recruited. The participants underwent structural magnetic resonance imaging and an evaluation of divergent thinking by using the Chinese version of the Abbreviated Torrance Test for Adults (ATTA). FreeSurfer 7.0 was used to generate thickness and surface area maps for each participant. Brainwise regression of the association between cortical thickness or surface area and ATTA performance was conducted using general linear models.

RESULTS

Divergent thinking performance did not differ significantly between the patients with BD and the healthy controls. In these patients, total ATTA score was negatively correlated with cortical thickness in the right middle frontal gyrus, right occipital, and left precuneus but positively correlated with the surface area of the right superior frontal gyrus. By contrast, total ATTA scores and cortical thickness or surface area were not significantly correlated among the controls.

CONCLUSION

The findings indicate that divergent thinking involves cerebral structures for executive control, mental imagery, and visual processing in patients with BD, and the right prefrontal cortex might be the most crucial of these structures.

Mapping the differential impact of spontaneous and conversational laughter on brain and mind: an fMRI study in autism

Spontaneous and conversational laughter are important socio-emotional communicative signals. Neuroimaging findings suggest that non-autistic people engage in mentalizing to understand the meaning behind conversational laughter. Autistic people may thus face specific challenges in processing conversational laughter, due to their mentalizing difficulties. Using fMRI, we explored neural differences during implicit processing of these two types of laughter. Autistic and non-autistic adults passively listened to funny words, followed by spontaneous laughter, conversational laughter, or noise-vocoded vocalizations. Behaviourally, words plus spontaneous laughter were rated as funnier than words plus conversational laughter, and the groups did not differ. However, neuroimaging results showed that non-autistic adults exhibited greater medial prefrontal cortex activation while listening to words plus conversational laughter, than words plus genuine laughter, while autistic adults showed no difference in medial prefrontal cortex activity between these two laughter types. Our findings suggest a crucial role for the medial prefrontal cortex in understanding socio-emotionally ambiguous laughter via mentalizing. Our study also highlights the possibility that autistic people may face challenges in understanding the essence of the laughter we frequently encounter in everyday life, especially in processing conversational laughter that carries complex meaning and social ambiguity, potentially leading to social vulnerability. Therefore, we advocate for clearer communication with autistic people.

The elephant in the room: attention to salient scene features increases with comedic expertise

What differentiates the joke writing strategy employed by professional comedians from non-comedians? Previous MRI work found that professional comedians relied to a greater extent on "bottom-up processes," i.e., associations driven by the prompt stimuli themselves, while controls relied more on prefrontal lobe directed, "top-down" processes. In the present work, professional improv comedians and controls generated humorous captions to cartoons while their eye movements were tracked. Participants' visual fixation patterns were compared to predictions of the saliency model (Harel et al. in Adv Neural Inf Process Syst 19:545-552, 2007)-a computer model for identifying the most salient locations in an image based on visual features. Captions generated by the participants were rated for funniness by independent raters. Relative to controls, professional comedians' gaze was driven to a greater extent by the cartoons' salient visual features. For all participants, captions' funniness positively correlated with visual attention to salient cartoon features. Results suggest that comedic expertise is associated with increased reliance on bottom-up, stimulus-driven creativity, and that a bottom-up strategy results, on average, in funnier captions whether employed by comedians or controls. The cognitive processes underlying successful comedic creativity appear to adhere to the old comedians' adage "pay attention to the elephant in the room."