Effects of harmony on cooperation in the context of conflicts of benefits

doi:10.3724/SP.J.1041.2026.2405

Abstract

Abstract: Cooperation is crucial for navigating conflicts of benefits, yet individuals vary greatly in their cooperative tendencies. Personality traits offer a key lens for understanding these differences; however, research on personality traits has predominantly focused on Western-based “Big Five” constructs and often overlooked culturally-specific, relationship-oriented traits. Harmony, a culturally relevant personality trait rooted in Eastern cultures that reflects a propensity to maintain interpersonal peace and avoid direct conflict, is a prime candidate for predicting cooperative behavior. This study systematically investigated whether and how harmony influences cooperation in conflict-of-interest scenarios. The study addressed two questions. First, does harmony consistently predict cooperative choices, and is the effect of harmony moderated by situational incentives? Second, what is the underlying interbrain synchronization (IBS) of this effect from a dyadic interaction perspective?
Two studies were conducted to address these questions. Study 1 was a questionnaire-based experiment involving 213 university participants (M_age = 21.69 years, 37.85% male). The participants completed the Harmony subscale of the Cross-Cultural (Chinese) Personality Assessment Inventory 2 and a hypothetical Prisoner’s Dilemma Game (PDG) task under two conditions (low vs. high cooperation incentive). Study 2 employed a two-person iterated PDG task combined with functional near-infrared spectroscopy (fNIRS) hyperscanning. The participants were prescreened on the basis of their harmony score and assigned to either high-harmony dyads (33 pairs) or low-harmony dyads (30 pairs). All participants in Study 2 were female to control for gender effects in social interaction. The task involved 120 rounds of real-time interaction, enabling the measurement of behavioral patterns and IBS.
The results of Study 1 showed that harmony positively predicted cooperative choices under both low-incentive (R² = 0.03, p = 0.014) and high-incentive (R² = 0.01, p = 0.001) conditions. The interaction between harmony and cooperation incentive was nonsignificant (F(1, 211) = 0.02, p = 0.89), which indicated that the predictive power of harmony was stable across different situational incentives. In Study 2, the behavioral results revealed a significantly higher rate of mutual cooperation in the high-harmony dyads than in the low-harmony dyads (M_high = 0.72 vs. M_low = 0.47, t (124) = 3.55, p < 0.001). Furthermore, the high-harmony individuals were more likely to adopt a “tit-for-tat” reciprocal strategy and less likely to engage in retaliation following a partner’s defection (interaction effect: F(3, 369) = 3.67, p = 0.009). The fNIRS hyperscanning results revealed a crucial moderating role of harmony: IBS was significantly increased during mutual cooperation but only within the high-harmony dyads. This enhanced synchronization occurred specifically in the left inferior frontal gyrus and the right medial temporal lobe. Critically, the level of IBS in the left dorsolateral prefrontal cortex (L-dlPFC) and left frontopolar area (L-FPC) during mutual cooperation was positively correlated with the dyad’s overall mutual cooperation rate, and this relationship was only significant for the high-harmony dyads (e.g., L-dlPFC: r = 0.71, p = 0.001, FDR corrected).
This study provides preliminarily evidence that the relationship-oriented personality trait (harmony) modulates IBS during cooperation, linking culturally relevant personality to the neural basis of social interaction. These findings may identify neural markers for cooperation, offering insights for enhancing team effectiveness and conflict resolution.

Key words: Harmony, cooperation, prisoner's dilemma, prefrontal cortex, interbrain synchronization (IBS)

SHU Jingyi, BAO Yaxin, MO Zhan, FAN Weiqiao, ZHANG Mingming. (2026). Effects of harmony on cooperation in the context of conflicts of benefits. Acta Psychologica Sinica, 58(11), 2405-2420.

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