情緒逆轉笑話的理解與欣賞之認知與情緒歷程：功能性磁振造影研究

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

詹雨臻(Yu-Chen Chan)

指導教授 ： 陳學志 ； 葉玉珠

國立臺灣師範大學/教育學院/教育心理與輔導學系/博士(2011年)

摘要

不論是古今或中外，幽默在人類的生理健康、心理調適和社交上，皆扮演重要的角色。因此，探討幽默歷程及其神經機制的研究蔚為風氣。近年來，先進的功能性磁振照影技術已經促使研究者以更有效的方法探討幽默歷程的大腦神經機制。過去的幽默研究，發現大腦進行幽默理解和幽默欣賞時，分別對應到不同的腦區。然而上述這些研究，大多以「好笑」和「不好笑」的條件相比，故其大腦的活化同時混雜著幽默的認知和情緒歷程，無法明確區分幽默理解的認知歷程與幽默欣賞的情緒成份之神經機制。因此，本研究採用過去幽默研究從未使用的實驗設計，在笑話語句與一般句之外，加入「歧義句」條件，以區分幽默的「認知成份」和「情緒成份」的神經機制。
　　此外，幽默的認知歷程可再細分為「失諧」和「解困」的歷程，然而過去的研究囿於刺激材料和實驗設計的限制，無法明確區分失諧與解困歷程所對應的神經機制。因此，本研究採用語文笑話，經由改寫關鍵語句，故以較精確操弄三種刺激類型：未失諧、失諧未解困、失諧解困。經由上述三類刺激的對比，可以更精細區分「失諧」和「解困」認知歷程的神經機制。
　　幽默具有從平靜情緒瞬間轉換成快樂情緒的功能，然而除了由中性轉換成正向情緒之笑話外，是否可能存在由負向逆轉成正向的笑話？此類負向逆轉成正向情緒的笑話理解歷程，是否和一般笑話逆轉的神經機制一樣呢？由於過去並未針對笑話情緒逆轉的研究結果，因此，本研究加入具有情緒逆轉的負向情緒笑話，比較一般笑話與負向情緒笑話之情緒逆轉歷程的神經機制。綜上所述，本研究分別以四個研究進行。
　　研究一對負向情緒笑話進行內容分析，結果發現從引發負向情緒的200則笑話中，以「恐怖到快樂」的笑話最多（佔30.5%），這類笑話在營造句會引發害怕情緒，到關鍵句則引發快樂情緒，具有情緒逆轉的特性。其餘負向笑話多半無法達到情緒逆轉的功能，因此，本研究選擇恐怖笑話作為後續研究之刺激材料。
　　研究二為建置一般笑話和恐怖笑話的情緒類別、理解程度和好笑程度評定之常模。過去笑話評定常模研究中，鮮少在營造句和關鍵句中同時評定情緒類別，來判斷該則笑話是否具有情緒逆轉之特性，因此以各60則的一般笑話和恐怖笑話為材料，由參與者分別評定在營造句和關鍵句的情緒類別，以及評定整則笑話的理解程度和好笑程度，以建立評定常模，並從中挑選出高度情緒逆轉、理解程度和好笑程度皆高的材料作為後續研究之用。
　　研究三採用心理測時術，分為二個實驗來測量個體在不同刺激類型的閱讀反應時間，並評定情緒類別、理解程度和好笑程度，再度確認實驗材料的有效性，並作為fMRI時間間隔操弄的依據。實驗一的獨變項為刺激類型：平靜－未失諧的平靜句（NCON）、平靜－失諧解困的歧義平靜句（NGP）、平靜－失諧解困的好笑句（NIR）、恐怖－未失諧的恐怖句（HCON）、恐怖－失諧解困的好笑句（HIR），依變項為情緒類別、理解程度和好笑程度。結果發現，NGP在關鍵句的反應時間顯著較久，一般笑話（NIR）比其他四種刺激的理解程度高，以及好笑程度比較好笑，符合理論預期。實驗二的獨變項為刺激類型：恐怖－未失諧的恐怖句（HCON）、恐怖－失諧未解困的恐怖句（HNEG）、恐怖－失諧未解困的正向句（HPOS）、恐怖－失諧解困的好笑句（HIR）。結果發現，四種刺激類型在營造句的反應時間未達顯著差異，出現關鍵句之後，恐怖笑話（HIR）在理解程度和好笑程度顯著高於其他三種刺激，皆符合理論預期。
　　研究四以事件相關功能性磁振照影技術進行二個實驗。實驗一旨在區分笑話中「認知成份」和「情緒成份」的神經機制，結果發現，幽默的認知成份引發語義統整在額上回和顳上回有較大的活化。在解困時，引發好笑愉悅的幽默情緒成份在海馬旁回、前扣帶回、腹內側前額葉皮質、腦島和杏仁核有較大的活化。實驗二旨在區分笑話中「失諧」和「解困」認知歷程的神經機制。結果發現，「失諧」歷程在額上回和額中回有較大的活化。「解困」歷程在額上回、顳上回有較大的活化。　
　　綜合兩個fMRI實驗結果，本研究提出兩個神經迴路模式，模式一為「幽默理解與欣賞的五階段神經迴路」：首先，失諧歷程的語義促發和選擇活化在額葉的「額回」，接著由「額上回」到顳葉的「顳上回」進行語義統整而獲得解困，再者激發頂葉的「角回」且再回到顳葉的「顳下回」進行語義和故事角色的人格特質推敲，進而由顳葉的大腦皮質至皮質下的「海馬旁回」和「前扣帶回」產生愉悅好笑的情緒感受，最後又回到額葉的「額上回」產生笑的行為反應。模式二可將幽默的情緒成份再區分為「快樂到幽默好笑之神經迴路」：快樂事件活化在「海馬旁回」，然而幽默欣賞所引發愉悅感受，是由海馬旁回再加上「前扣帶回」才會產生好笑的情緒感受，因此，前扣帶回在幽默欣賞中扮演重要的角色。
　　綜上所述，相較於過去的幽默研究，本研究的實驗設計有所突破，更能釐清且區分幽默的「認知成份」與「情緒成份」之神經機制，且在幽默理解可再區分出「失諧」和「解困」的歷程，也能比較不同情緒逆轉的笑話類型之神經機制，對於瞭解幽默的神經機制具有重大的貢獻。未來研究可再進一步比較幽默與情緒調節的效果。其次，本研究採用二段式笑話結構，未來可使用三段式笑話結構，從刺激材料更能清楚區分失諧和解困的歷程。再者，本研究的參與者皆為一般正常人，未來可和不同族群進行比較，如和亞斯柏格者比較在笑話中認知與情緒歷程之神經運作機制。

關鍵字

事件關聯功能性磁振造影 ； 恐怖笑話 ； 情緒逆轉 ； 額上回 ； 顳上回 ； 前扣帶回 ； 海馬旁回

並列摘要

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.

並列關鍵字

event-related fMRI ； horror jokes ； emotional reversal ； superior frontal gyrus ； superior temporal gyrus ； anterior cingulate cortex ； parahippocampal gyrus

參考文獻

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