Department of Cognitive Neuroscience, ATR Brain Information Communication Research Laboratory Group, Kyoto 619-0288, Japan, Institute of Social and Economic Research, Osaka University, Osaka 567-0047, Japan, Faculty of Economics, Kindai University, Higashi-Osaka 577-0813, Japan, and Pharmaceutical Policy & Health Economics, Kyoto University, Kyoto 606-8501, Japan.
J Neurosci. 2014 Apr 16;34(16):5595-602. doi: 10.1523/JNEUROSCI.5169-12.2014.
Humans typically discount future gains more than losses. This phenomenon is referred to as the "sign effect" in experimental and behavioral economics. Although recent studies have reported associations between the sign effect and important social problems, such as obesity and incurring multiple debts, the biological basis for this phenomenon remains poorly understood. Here, we hypothesized that enhanced loss-related neural processing in magnitude and/or delay representation are causes of the sign effect. We examined participants performing intertemporal choice tasks involving future gains or losses and compared the brain activity of those who exhibited the sign effect and those who did not. When predicting future losses, significant differences were apparent between the two participant groups in terms of striatal activity representing delay length and in insular activity representing sensitivity to magnitude. Furthermore, participants with the sign effect exhibited a greater insular response to the magnitude of loss than to that of gain, and also a greater striatal response to the delay of loss than to that of gain. These findings may provide a new biological perspective for the development of novel treatments and preventive measures for social problems associated with the sign effect.
人类通常更倾向于低估未来的收益，而高估未来的损失。这种现象在实验经济学和行为经济学中被称为“符号效应”。尽管最近的研究报告了符号效应与肥胖和多重债务等重要社会问题之间的关联，但人们对这种现象的生物学基础仍知之甚少。在这里，我们假设在幅度和/或延迟表示中增强的与损失相关的神经处理是符号效应的原因。我们检查了参与者执行涉及未来收益或损失的跨期选择任务，并比较了表现出符号效应和没有表现出符号效应的参与者的大脑活动。在预测未来损失时，两组参与者的纹状体活动代表延迟长度和岛叶活动代表对幅度的敏感性存在明显差异。此外，具有符号效应的参与者对损失幅度的岛叶反应大于对收益幅度的反应，对损失延迟的纹状体反应也大于对收益延迟的反应。这些发现可能为与符号效应相关的社会问题的新型治疗和预防措施的开发提供新的生物学视角。
