Intraparietal stimulation disrupts negative distractor effects in human multi-alternative decision-making

There has been debate about whether addition of an irrelevant distractor option to an otherwise binary decision influences which of the two choices is taken. We show that disparate views on this question are reconciled if distractors exert two opposing but not mutually exclusive effects. Each effect predominates in a different part of decision space: 1) a positive distractor effect predicts high-value distractors improve decision-making; 2) a negative distractor effect, of the type associated with divisive normalisation models, entails decreased accuracy with increased distractor values. Here, we demonstrate both distractor effects coexist in human decision making but in different parts of a decision space defined by the choice values. We show disruption of the medial intraparietal area (MIP) by transcranial magnetic stimulation (TMS) increases positive distractor effects at the expense of negative distractor effects. Furthermore, individuals with larger MIP volumes are also less suscep..., , To run the scripts included in this repository, MATLAB and VBA toolbox (https://mbb-team.github.io/VBA-toolbox/) are required. The scripts included were written and run using MATLAB R2018a.学界此前围绕二元决策场景中添加无关干扰选项是否会影响最终二选一的选择这一议题存在诸多争议。我们的研究证实，若干扰项同时具备两种对立且非互斥的作用，则该问题的分歧观点可得到调和。两类干扰效应在决策空间的不同区域占据主导地位：其一为正向干扰效应，即高价值干扰项可改善决策表现；其二为负向干扰效应，该效应与除法归一化模型（divisive normalisation models）的相关结论一致，表现为随干扰项价值提升，决策准确率下降。本研究表明，人类决策行为中确实同时存在这两种干扰效应，且分别存在于由选项价值定义的决策空间的不同区域。我们还发现，经颅磁刺激（Transcranial Magnetic Stimulation, TMS）对内侧顶内沟（Medial Intraparietal Area, MIP）的干预会增强正向干扰效应，同时以削弱负向干扰效应为代价。此外，内侧顶内沟体积更大的个体也更不易……（原文内容被截断），若要运行本仓库包含的脚本，需安装MATLAB及VBA工具箱（https://mbb-team.github.io/VBA-toolbox/），相关脚本均基于MATLAB R2018a编写并运行。