Cognitive and neural humor processing : the influence of structural stimulus properties and theory of mind
Thèse de doctorat : Université de Fribourg, 2008.
The aim of the present dissertation is to broaden the knowledge of cognitive humor processes that are the basis of humor appreciation through a multidisciplinary approach: psychological as well as cognitive-linguistic humor theories were taken into account. The focus of interest lies mainly on the incongruity-resolution step of humor processing in relation to structural properties of humorous... PlusAjouter à la liste personnelle
- The aim of the present dissertation is to broaden the knowledge of cognitive humor processes that are the basis of humor appreciation through a multidisciplinary approach: psychological as well as cognitive-linguistic humor theories were taken into account. The focus of interest lies mainly on the incongruity-resolution step of humor processing in relation to structural properties of humorous stimuli as well as individual differences in experience seeking, empathy and systemizing skills. Neuronal correlates—measured by means of functional Magnetic Resonance Imaging (fMRI)—as well as several behavioral measures were used: questionnaires, rating scales as well as explanations of the punch line. Three central themes were addressed: 1) cognitive and affective processes (particularly incongruity-resolution) of visual humorous material, i.e., non-verbal cartoons, 2) the influence of structural properties such as Logical Mechanisms (LMs), as well as incongruity-resolution vs. nonsense humor on neuronal correlates of humor processing, and 3) the relationship between Theory of Mind and humor—Theory of Mind as stimulus characteristic (what cognitive skills are required in order to understand the punch line correctly) and as mental ability (and closely related to empathy) that can vary within subjects. The results revealed the following network to be involved in incongruity-resolution without pre-processing steps: ventro-medial prefrontal cortex, inferior frontal gyrus, temporo-parietal junction (TPJ) and supramarginal gyrus. The rostral cingulate zone—an area known to be involved in conflict monitoring and error processing—was activated only during the unsuccessful attempt to understand a joke in a picture that contained an irresolvable incongruity. Furthermore, several LMs, i.e., the cognitive rule how the incongruity has to be resolved, moderated neural activation patterns during humor processing. Whereas semantic cartoons required the above-mentioned neural network, more specific areas were involved for processing visual puns (higher-order visual areas) and Theory of Mind cartoons (so-called mentalizing areas). On the one hand, this shows that LMs influence humor processing, on the other hand that Theory of Mind is not always involved in humor processing, as “mentalizing” areas were not involved in visual puns and only to a lesser degree in semantic cartoons. Moreover, incongruity-resolution humor (i.e., humorous stimuli that can always completely be resolved) evokes more brain activation than nonsense humor (i.e., the incongruity of the joke cannot be completely resolved, much residual incongruity remains), particularly in the TPJ—an area that is involved in integrating information or coherence building. It can therefore be concluded that structural mechanisms—be it LMs or the resolvability of the incongruity (incongruity-resolution and nonsense humor)—influence neural correlates of humor processing. Furthermore, experience seeking—a personality variable known to influence humor processing—was shown to affect neural activation patterns: higher experience-seeking scores lead to increased activation in prefrontal, posterior temporal regions and the hippocampus. This might be due to a more intense exploration of the humorous stimuli as experience seekers tend to search novel mental stimulation. Furthermore, experience seeking leads to increased brain reactivity during the processing of nonsense in contrast to incongruity-resolution humor, which is in line with behavioral studies that showed that experience seekers prefer nonsense humor. Furthermore, empathizing and systemizing was shown to influence processing of humorous stimuli with different LMs: for example, empathizers more often give emotional/motivational and more mentalistic explanations as to why they think a cartoon is funny—particularly in Theory of Mind cartoons. As typical mentalistic explanations occur more often in Theory of Mind cartoons and are uttered more often by individuals with high scores on empathizing, it can be concluded that mentalizing is not always involved to the same degree in humor processing: it depends on stimulus as well as individual characteristics. In conclusion, these studies show that stimulus characteristics (such as LMs or the resolvability of the incongruity) and inter-individual differences (experience seeking, empathizing, systemizing) influence cognitive as well as affective humor processing. This is the first empirical evidence that LMs influence humor processing. Furthermore, present studies show that mentalizing is not always involved in humor processing, since not all humorous stimuli evoke activation in “mentalizing” areas or provoke mentalistic explanations. This might help to better understand the underlying processes of humor appreciation but also opens more research questions that have to be addressed in the future.