功能性磁振造影研究：公平於競爭與合作人際情境中對社會互動之影響

Abstract

競爭與合作是為獲取資源而存在的兩種社會人際互動方式。人們會運用心智中的「人我能力」(Self-other abilities)進行競爭與合作。若在競爭與合作的互動中，處於不同公平性的資源分配下，會影響競爭與合作互動中「人我能力」的運用。本實驗透過線上互動式俄羅斯方塊遊戲(reciprocal Tetris game)來創造出競爭與合作互動，並於其中操弄額外的起始分數(initial bonus scores)以創造不同公平性的條件並尋求在競爭與合作中對「人我能力」造成的差異。此外，優勢不公平(Advantage unfairness)也在本實驗中被引入與傳統上所論之不公平(Unfairness)，或稱劣勢不公平( Disadvantage unfairness)進行比較。 本研究共有16個自願者參與，從行為結果上發現，競爭中受試者的表現會與互動時的內側前額葉皮質(medial prefrontal cortex)有正相關；而在合作中受試者與對手共同產出的合作成果會與左側眼眶前額葉皮質(left orbital frontal cortex)有正相關。此結果支持競爭與合作中的受試者所著重的成果表現與大腦中不同的區域相關。 在競爭與合作活動中，均有出現與「人我能力」相關的腦區，包含內側前額葉皮質、右側頂下葉(right inferior parietal lobe)。這些腦區在不公平的資源分配條件下，相較於公平時，在競爭中會有較強的活化，但此差異於合作中卻未顯著。此結果支持當人們處於不公平的資源分配條件下與對手競爭時，會運用較多的「人我能力」以達到競爭爭奪資源之目的。優勢不公平相較於劣勢不公平，在競爭中與「人我能力」相關的腦區也有較強活化，此結果支持處於優勢不公平的條件下，受試者運用的「人我能力」也會較劣勢時為多。行為指標中受試者與對手得分的差異與金錢獎酬上的差異均可反應受試者在資源分配中的優勢程度，這兩個行為指標也與大腦中的內側前額葉皮質有正相關，此結果亦指出，處於優勢不公平的條件中，人們會較劣勢時運用更多的心智化能力(mentalizing) 於競爭互動之中。

Competition and cooperation are two fundamental social interactions for obtaining resources. In both interactions, the self-other abilities are involved and affected by different fairness in resource distribution. In this research, competitive and cooperative interactions are implemented in the interactive on-line Tetris game (reciprocal Tetris game) and two initial bonus scores are manipulated for creating different fairness in resources distribution for competitive and cooperative conditions. In addition, the advantage unfairness, which means the participants are advantageous than their opponents in terms of resources, is introduced in this study and compared with traditional unfairness (i.e. disadvantage unfairness). Sixteen participants are involved in this study. According to their behavioral result, the performance of the participants is positively correlated with medial prefrontal cortex (MPFC). The cooperative accomplishment generated by the cooperation of the participants and their opponents are positively correlated with left orbital frontal cortex (LOFC). These results suggest that the performance in competition and the cooperative accomplishment in cooperation are related to different regions in brain. The activations of the brain regions related to the self-other abilities including MPFC and right inferior parietal lobe (RIPL) are shown in both competitive and cooperative conditions. Greater activations of the brain regions above are shown in the contrast of “Unfair versus Fair” in competition but not significant in cooperation. This result suggests that people uses more self-other abilities for competing resources in the unfair condition than the fair condition. In addition, the greater activations of same brain regions are shown in the contrast of “Advantage versus Disadvantage” in unfair competition. This result suggests that people uses more self-other abilities for competing resources in the advantageous condition than the disadvantageous condition. The advantageous degree of the participants, represented by the difference between the participants and their opponents in scores and monetary rewards, are positively correlated with MPFC. This result suggests that people uses more mentalizing ability in the advantageous condition than the disadvantageous condition.