Kawamichi Hiroaki, Sugawara Sho K, Hamano Yuki H, Makita Kai, Kochiyama Takanori, Sadato Norihiro
Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, 116-8551 Japan.
Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences, Okazaki, 444-8585 Japan.
Sci Rep. 2016 Apr 19;6:24561. doi: 10.1038/srep24561.
Positive social interactions contribute to the sense that one's life has meaning. Enjoyment of feelings associated through social interaction motivates humans to build social connections according to their personal preferences. Therefore, we hypothesized that social interaction itself activates the reward system in a manner that depends upon individual interaction preferences. To test this hypothesis, we conducted a functional magnetic resonance imaging (fMRI) study in which 38 participants played a virtual ball-toss game in which the number of ball tosses to the participant was either similar to (normal-frequency condition) or higher than (high-frequency condition) the number of tosses to the other players. Participants reported greater-than-anticipated enjoyment during the high-frequency condition, suggesting that receiving a social reward led to unexpected positive feelings. Consistent with this, the high-frequency condition produced stronger activation in the ventral striatum, which is part of the reward system, and the precuneus, representing positive self-image, which might be translated to social reward. Furthermore, ventral striatal activation covaried with individual participants' preference for interactions with others. These findings suggest that an elevated frequency of social interaction is represented as a social reward, which might motivate individuals to promote social interaction in a manner that is modulated by personal preference.
积极的社会互动有助于让人感受到生活的意义。通过社会互动所产生的情感享受促使人类根据个人喜好建立社会联系。因此，我们假设社会互动本身会以一种取决于个人互动偏好的方式激活奖赏系统。为了验证这一假设，我们进行了一项功能磁共振成像（fMRI）研究，38名参与者参与了一场虚拟抛球游戏，在游戏中抛给参与者的球的次数与抛给其他玩家的次数相似（正常频率条件）或高于（高频条件）抛给其他玩家的次数。参与者报告称在高频条件下获得了比预期更大的愉悦感，这表明获得社会奖赏会带来意想不到的积极感受。与此一致的是，高频条件下奖赏系统的一部分腹侧纹状体以及代表积极自我形象的楔前叶产生了更强的激活，这种激活可能转化为社会奖赏。此外，腹侧纹状体的激活与个体参与者对与他人互动的偏好相关。这些发现表明，社会互动频率的提高被视为一种社会奖赏，这可能会促使个体以一种受个人偏好调节的方式促进社会互动。
