Corpus Callosum Dysgenesis is concomitant with reduced metacognitive efficiency and sensitivity across multiple cohorts and modalities

The corpus callosum is the largest commissure in the mammalian brain and has been implicated in supporting cognitive processes required for adapting to complex environments. Individuals born with Corpus Callosum Dysgenesis, characterized by malformations of the corpus callosum, commonly exhibit deficits in social navigation, abstract problem-solving, decision-making, and self-awareness. Metacognition is a key cognitive process that supports these functions; however, it has yet to be tested comprehensively in individuals with Corpus Callosum Dysgenesis. Over three experiments, and three Corpus Callosum Dysgenesis cohorts, we examine perceptual accuracy, confidence judgments, and metacognitive efficiency in individuals with Corpus Callosum Dysgenesis using two variants of a Random Dot Kinematogram task within lab, online, and virtual reality conditions. We find that individuals with Corpus Callosum Dysgenesis typically display normal perceptual accuracy but fail to adjust their confidence judgments in line with task difficulty. Computational modeling reveal that this difference is characterized by lower metacognitive efficiency concomitant with lower metacognitive sensitivity. Together, these results provide evidence that the corpus callosum is consistently associated with reduced metacognitive efficiency.