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

Pereira M, Faivre N, Iturrate I, Wirthlin M, Serafini L, Martin S, Desvachez A, Blanke O, Van de Ville D, Millan JDR.

Significance

Our sense of confidence stems from the evidence leading to those decisions. This has made the study of confidence in isolation from decisional processes difficult. We devised a task in which participants rate their confidence in their own decisions or in observed decisions that are thus unrelated to decisional processes. We propose a computational account of the mechanisms underlying confidence in both conditions and reproduce participants’ behavior. Furthermore, we show that activity in the inferior frontal gyrus relates to confidence, even when confidence is unrelated to decisional processes. Activity in the frontal pole and insula was more related to confidence when related to participants’ own decisions. Our study provides evidence on the mechanisms and neural implementation of confidence.

Abstract

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 cooccurs with decision making. Here, we isolated postdecisional from decisional contributions to metacognition by analyzing neural correlates of confidence 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 postdecisional 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.