中国科学院行为科学重点实验室知识库

目的探究单次经颅直流电刺激干预双侧背外侧前额叶皮层对正常成年人公平决策行为的影响。方法 2018年9月至2019年2月招募60名年龄在18～45周岁之间的健康被试, 随机分为3组:左阳/右阴组、左阴/右阳组、假刺激组, 每组20人。3组分别进行双侧背外侧前额叶脑区的左侧阳极刺激/右侧阴极刺激、左侧阴极/右侧阳极刺激和双侧对照电极(假刺激)的经颅直流电刺激干预。刺激结束后, 立即依次完成最后通牒游戏任务、公平性评分问卷。采用SPSS 22.0统计软件中的重复测量方差分析、非参数检验对数据进行分析。结果最后通牒游戏任务中, 3组被试作为方案回应者在各公平水平的接受率上差异无统计学意义(均P>0.05)。配对样本秩和检验分析3种刺激类型组在不同公平水平条件下, 面对不同提议者("计算机"和"人")的接受率差异时发现, 假刺激组对人类对手提出的极不公平方案的接受率低于计算机提出的极不公平方案[0.28 (0, 0.67), 0.44 (0.33, 0.89), Z=-2.14, P=0.032], 而在面对计算机和人类对手提出的公平或不公平方案时, 接受率均差异无统计学意义(均P>0.05);左阴/右阳组在面对人类对手提出的不公平[0.90 (0.50, 1.00), 1.00 (0.70, 1.00), Z=-1.90, P=0.046]或极不公平[0.44 (0, 1.00), 0.89 (0.50, 1.00), Z=-2.73, P=0.006]方案时接受率均显著低于计算机对手, 而在面对计算机和人类对手提出的公平方案时, 接受率差异无统计学意义(P>0.05);左阳/右阴组在面对计算机和人类对手提出的公平、不公平以及极不公平方案时, 接受率均差异无统计学意义(均P>0.05)。对于公平性评分, 重复测量方差分析结果显示组别和提议者类型交互效应不显著(F(2, 54)=2.037, P=0.140), 组别主效应不显著(F(1, 54)=0.165, P=0.848), 但提议者类型主效应显著(F(1, 54)=6.363, P=0.015), 对人类提议者所提方案的公平性评分低于计算机提议者(P<0.05)。结论单次双侧背外侧前额叶皮层的经颅直流电刺激虽然对公平决策整体接受率无明显影响, 但影响了面对人或计算机提出的不公平分配方案的决策。

Objective

To investigate the effect of a single-trial transcranial direct current stimulation(tDCS) of the dorsolateral prefrontal cortex (DLPFC) on fairness-related decision-making behavior.

Methods

From September 2018 to February 2019, a total of 60 healthy participants between the ages of 18 and 45 were enrolled.Then, the participants were randomly divided into 3 groups with 20 in each group to receive left anode stimulation/right cathode stimulation (left anode /right cathode group), left cathode/right anode stimulation (left cathode /right anode group) or bilateral control electrodes (sham stimulation group) on the bilateral dorsolateral prefrontal cortices (DLPFC), respectively.After tDCS, the participants immediately completed the ultimatum game (UG) task as responders and a fairness questionnaire in turn.SPSS 22.0 statistical software was used to analyze the data with repeated measurement ANOVA and nonparametric test.

Results

In the UG task, there was no significant difference in the acceptance rate among the three groups of participants as responders (all P>0.05). When analyzing the acceptance rate facing different proposers (" computer" and " human" ) under different fairness levels in the three stimulus types through the paired samples Wilcoxon test, it was found that the acceptance rate of the sham stimulation group to the extremely unfair proposals proposed by the human opponent was lower than that proposed by the computer(0.28 (0, 0.67), 0.44 (0.33, 0.89), Z=-2.14, P=0.032), while there was no difference in acceptance rates (both P>0.05) in the face of fair or unfair proposals proposed by computer and human opponents.The acceptance rate of the left cathode /right anode group to the unfair(0.90 (0.50, 1.00), 1.00 (0.70, 1.00), Z=-1.90, P=0.046)or extremely unfair(0.44 (0, 1.00), 0.89 (0.50, 1.00), Z=-2.73, P=0.006) proposals proposed by human opponents was significantly lower than the proposals proposed by computer opponent, and there was no differences in acceptance rate when facing fair proposals proposed by computer and human opponents (P> 0.05). There were no significant differences in acceptance rates in the left anode /right cathode group when faced with fair, unfair, and extremely unfair schemes proposed by computer and human opponents (all P>0.05). For fairness questionnaire scores, a repeated measurements ANOVA showed that the interaction effect between group and proposer types was not significant (F(2, 54)=2.037, P=0.140), and the group main effect was not significant (F(1, 54)=0.165, P=0.848), but the proposer type main effect was significant (F(1, 54)=6.363, P=0.015), indicating that the fairness questionnaire score in the face of the human opponents was lower than when facing the computer opponents(P<0.05).

Conclusion

Although a single-trial tDCS on bilateral DLPFC has no significant effect on the overall acceptance rate of fairness-related decision-making, it affects the decision-making of unfair distribution scheme proposed by human or computer.

国家自然科学基金(81771473)