Disentangling the origins of confidence in speeded perceptual judgments through multimodal imaging

The human capacity to compute the likelihood that a decision is correct - known as metacognition - has proven difficult to study in isolation as it usually co-occurs with decision-making. Here, we isolated post-decisional from decisional contributions to metacognition by combining a novel paradigm with multimodal imaging. Healthy volunteers reported their confidence in the accuracy of decisions they made or decisions they observed. We found better metacognitive performance for committed vs. observed decisions, indicating that committing to a decision may improve confidence. Relying on concurrent electroencephalography and hemodynamic recordings, we found a common correlate of confidence following committed and observed decisions in the inferior frontal gyrus, and a dissociation in the anterior prefrontal cortex and anterior insula. We discuss these results in light of decisional and post-decisional accounts of confidence and propose a computational model of confidence in which metacognitive performance naturally improves when evidence accumulation is constrained upon committing a decision.

人类对于评估决策正确性的可能性——即元认知能力——在独立研究时已被证明是一项艰巨的任务，因为这一能力通常与决策过程相伴而生。在本研究中，我们通过结合一种新颖的范式和多模式成像技术，成功地将元认知过程中的后决策贡献与决策贡献进行了分离。健康志愿者报告了他们对所做决策或观察到的决策准确性的信心程度。我们发现，在承诺决策与观察决策之间，元认知表现存在显著差异，暗示着对决策的承诺可能有助于提升信心。借助同步进行的脑电图和血流动力学记录，我们发现在前扣带回和前岛叶中，承诺决策与观察决策后的信心水平存在共同的相关性，而在前额叶皮层和前岛叶之间则出现了分离现象。我们基于决策过程与后决策过程对信心的解释，对这些研究结果进行了深入探讨，并提出了一种信心计算模型，该模型认为，当证据积累在决策承诺的约束下进行时，元认知表现将自然得到提升。