The Cognitive and Emotional Processing of Emotional Reversal Jokes: An fMRI Study

• Main Authors: Yu-Chen Chan, 詹雨臻
• Other Authors: Hsueh-Chih Chen
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/40857506624986786968

博士 === 國立臺灣師範大學 === 教育心理與輔導學系 === 99 === 　　Humor plays a crucial role in the physical, psychological, and social well-being of all human beings, regardless of time and place. Consequently, extensive research and experimentation has been performed focusing on comprehending the humor process and its neural substrates. In recent years, technical advances in functional magnetic resonance imaging have enabled researchers to more effectively investigate the neural substrates of humor processing. Previous studies have discovered that humor comprehension and humor appreciation appear to be managed by different brain regions. However, most of the preceding studies have explored this topic by contrasting “funny” and “nonfunny” conditions. These two conditions both activate brain regions involved with the processing of the cognitive and emotional aspects of humor and thus do not allow for the identification of the distinct neural substrates underlying each of these taken as separate sets of processes. To overcome this difficulty, this study was the first to adapt an experimental designed to identify the distinct neural substrates of cognitive and emotional processing. This is done through the incorporation of a “garden path sentence”. 　　A further obstacle encountered in the previous research is that it has been difficult to clearly identify the neural substrates contributing to the subdivision of “incongruity” and “resolution.” To further investigate this, I rewrote the punch lines of verbal jokes to generate stimuli jokes of three types: incongruity-removed, resolution-removed, and incongruous resolution jokes. By contrasting the results from these three types, it was possible to clearly identify the neural substrates of the cognitive processes associated with “incongruity” and “resolution.” 　　One essential mechanism of humor involves the sudden shift from a calm to a happy emotional state. However, aside from this type of change from a neutral to a positive emotional state, are there jokes which actually reverse the recipient’s emotional state, from negative to positive? If so, is the comprehension process for such jokes the same as that for general (neutral to positive state) jokes? As no existing research on this topic was found in a review of the literature, this study also included an investigation of such ‘emotional-reversal’ jokes, both documenting their existence and comparing their processing with that of regular jokes. This study was composed of the following four sub-studies. 　　Study 1 was a content analysis of jokes involving negative emotions. It was discovered that of 200 jokes that invoke negative emotions, most fall in the “fear to happiness” category (30.5%). These jokes build up fear-related tension during the joke set-up, and then produce a burst of happiness at the punch line. The movement from the set-up to the punch line thus leads to an ‘emotional reversal.’ The remaining jokes in the negative emotion category could not be said to achieve this function. Therefore, the “fear to happiness” jokes were selected for use as stimuli in the following studies. 　　Study 2 established rating norms for the emotion categories, the comprehension level, and the ‘funniness’ level of the regular jokes and the horror jokes. In past studies of joke rating norms, set-up lines were rarely rated together with punch lines as a parameter to judge whether a joke contained ‘emotion reversal’ qualities. To establish the norms for this study, we utilized 60 regular and 60 horror jokes as material, and asked participants to rate the set-up lines as well as the punch lines according to their emotion categories, and to evaluate the level of comprehensibility and funniness of the punch lines. Among the 120 jokes, we selected jokes with high emotion reversal rates, high comprehensibility, and high funniness level as material for the following study. 　　Study 3 adopted mental chronometry to perform two sets of experiments measuring the reaction time of participants reading different types of stimuli. Emotion category, comprehension level, and funniness level were evaluated again here to ensure the validity of the chosen materials. Results in this study were used to establish the foundation for the fMRI time interval manipulation. 　　In experiment 1, the independent variable was the stimuli type, with five possible values: calm incongruity-removed-calm sentence (NCON), calm incongruity-resolution-garden path-calm sentence (NGP), calm-incongruity-resolution-joke (NIR), horror incongruity-removed-horror sentence (HCON), and horror incongruity-resolution-joke (HIR). The dependent variables were the emotion category, the comprehension rate and the funniness rate. The results show that reaction time to NGP at the punch line was clearly longer than that for all other types, and regular jokes (NIR) has comparatively higher ratings on comprehensibility and funniness than did the other four types of stimuli, which is consistent with our theory. 　　The independent variable in experiment 2 was also stimuli type, with the following categories: horror incongruity-removed-horror sentence (HCON), horror resolution-removed-horror sentence (HNEG), horror resolution-removed-positive sentence (HPOS), and horror incongruity-resolution joke (HIR). No significant differences in reaction time from the set-up lines for all 4 stimuli types were found. Horror jokes (HIR) had a higher degree of comprehensibility and funniness than the other 3 types. This was also consistent with theoretical expectations. 　　Study 4 included two event-related fMRI experiments. The purpose of experiment 1 was to identify the distinct neural substrates associated with cognitive processing and emotional processing. The five stimulus conditions were: NCON, NGP, NIR, HCON, and HIR. The results indicate that cognitive processing involves activation of the semantic intergration area, including the superior frontal gyrus and the superior temporal gyrus. Emotional processing of humor triggers higher activation in the area associated with the experience of amusement, including the parahippocampal gyrus, the anterior cingulate cortex, the ventral medial prefrontal gyrus, the insula and the amygdala. 　　The target of experiment 2 was to distinguish neural substrates in the cognitive processing of “incongruity” and “resolution”. The four stimulus conditions included HCON, HNEG, HPOS, and HIR. The results indicate that “incongruity” processing involved activation in the superior frontal gyrus and middle/medial frontal gyri. In addition, “resolution” processes were associated with high levels of activation in the superior frontal gyrus and the superior temporal gyrus. 　　These two fMRI experiments suggest two distinct neural circuits. The first is involved with the cognitive and affective processing of humor and can be called the “Five-step Neural Circuit of Humor Comprehension and Appreciation.” It starts with the process of semantic activation and identification of humor incongruity in the frontal gyrus on the frontal lobe, followed by semantic integration processed by the superior temporal gyrus from the superior frontal gyrus to the temporal lobe, which achieves resolution, and moves to the angular gyrus on the parietal lobe and then returns to the inferior temporal gyrus of the temporal lobe to process elaboration of the semantic characteristics of the protagonist in the story. In the fourth step, processed in the cerebral cortex at the temporal lobe to the subcortex, the parahippocampal gyrus and the anterior cingulated cortex produce a ‘funny’ feeling. In the fifth and final step, the process returns to the superior frontal gyrus at the frontal lobe to generate the action of laughter. The second circuit, called here the “Neural Circuit from Happiness to Funniness”, is initiated when the parahippocampal gyrus is activated by a happy event. However, the pleasant feeling from humor appreciation only becomes funny when the parahippocampal gyrus and the anterior cingulated cortex are both activated. Hence, the anterior cingulated cortex plays a crucial role in humor appreciation. 　　In summary, this study provides a breakthrough in experimental design in humor research, with the potential to allow for the identification of the neural substrates of the cognitive components and emotional components of humor, and the “incongruity” and “resolution” processes associated with humor comprehension. By comparing the neural substrates associated with the processing of ‘emotional reversal’ jokes, this study also contributes to understanding the neural substrate of humor. It is demonstrated that humor cognition and emotion highly activate distinctive areas in the cortex and subcortex, and by observing changes in the areas activated during shifts of emotional states, we were able to associate humor comprehension and appreciation processes with different brain areas. Extended studies in this topic could be conducted by comparing the effectiveness of humor and emotion regulation. Additionally, this study adopted a two-stage joke structure in the experiment, which could also be replaced with a three-stage joke structure to clearly trace the incongruity and resolution process. Finally, the participants in this study were all ‘normal’ people. The data could thus be used as a baseline against which results from participants with Asperger’s syndrome could be compared to further investigate the neural substrates of cognitive and emotional processing of jokes in different groups.