A decision-congruent heuristic gives superior metacognitive sensitivity under realistic variance assumptions

Psychophysical studies on confidence construction are often grounded in bidimensional signal detection theory (SDT) and its relatives. However, these studies often stand on oversimplified assumptions of (a) bidimensional variance-equality and (b) bidimensional statistical independence. The present study simulated 2-alternative forced-choice and confidence rating performances, incorporating more empirically plausible variance-covariance structures. One prominent observation is that superior metacognitive accuracy can be achieved when one applies a heuristic in which the response-incongruent dimension of information is ignored. This is because such an heuristic takes advantage of the specific unequal-variance structure, which paradoxically cannot be easily exploited if both dimensions are evaluated together. Furthermore, under a variety of internal statistical structures, this simple heuristic predicts dissociations of objective decision and subjective metacognition, which have been empirically observed. Also, it provides a tentative account of some behavioral features of blindsight. Therefore, this surprisingly simple decision heuristic may inspire novel perspectives on metacognition and consciousness. (PsycInfo Database Record (c) 2020 APA, all rights reserved).