Halko Marja-Liisa, Hlushchuk Yevhen, Hari Riitta, Schürmann Martin
Brain Research Unit, Low Temperature Laboratory, Helsinki University of Technology, 02015 TKK, Espoo, Finland.
Neuroimage. 2009 Jun;46(2):542-8. doi: 10.1016/j.neuroimage.2009.01.063.
Competition imposes constraints for humans who make decisions. Concomitantly, people do not only maximize their personal profit but they also try to punish unfair conspecifics. In bargaining games, subjects typically accept equal-share offers but reject unduly small offers; competition affects this balance. Here we used functional magnetic resonance imaging (fMRI) to study adjustment to competition in a bargaining game where subjects competed against another person for a share of the stake. For medium-sized, but not for minimum offers, competition increased the likelihood of acceptance and thus shifted behavior towards maximizing personal profits, emphasizing the importance of financial incentives. Specifically for medium-sized offers, competition was associated with increased brain activation bilaterally in the temporo-parietal junction, a region associated with mentalizing. In the right inferior frontal region, competition-related brain activation was strongest in subjects whose high acceptance rates in the standard ultimatum game hinted at a profit-oriented approach. The results suggest a network of brain areas supporting decision making under competition, with incentive-dependent mentalizing engaged when the competitor's behavior is difficult to predict and when the stake is attractive enough to justify the effort.
竞争给做决策的人带来了限制。与此同时，人们不仅会最大化个人利益，还会试图惩罚不公平的同类。在讨价还价博弈中，受试者通常会接受均分提议，但会拒绝过小的提议；竞争会影响这种平衡。在此，我们使用功能磁共振成像（fMRI）来研究在一种讨价还价博弈中对竞争的适应情况，在该博弈中，受试者与另一个人竞争以获取一份赌注。对于中等规模的提议，而非最低提议，竞争增加了接受的可能性，从而使行为朝着最大化个人利益转变，这强调了经济激励的重要性。具体而言，对于中等规模的提议，竞争与双侧颞顶联合区大脑激活增加有关，该区域与心理理论相关。在右下额叶区域，竞争相关的大脑激活在标准最后通牒博弈中接受率高且暗示着以利益为导向方法的受试者中最为强烈。结果表明存在一个支持竞争情境下决策的脑区网络，当竞争对手的行为难以预测且赌注足够有吸引力以证明努力的合理性时，会涉及依赖激励的心理理论。
