Insights into the molecular genetic basis of individual differences in metacognition.

• We linked three genetic polymorphisms with behaviorally measured metacognition. • We found higher metacognitive bias in S/L G -allele carriers in the 5-HTTLPR genotype. • This is discussed with regard to the role of the S-allele as a plasticity variant. • The serotonergic system partially mediates metacognitive bias. There is a striking lack of studies on the molecular genetic basis of metacognition, i.e., the higher-order ability to monitor mental processes. Here, an initial step toward resolving this issue was undertaken by investigating functional polymorphisms from three genes of the dopaminergic or serotonergic systems (DRD4, COMT , and 5-HTTLPR) in relation to behaviorally assessed metacognition in six paradigms across three cognitive domains. We report evidence for a task-dependent higher average confidence level (metacognitive bias) in carriers of at least one S or L G -allele in the 5-HTTLPR genotype and integrate these findings within a differential susceptibility framework. [ABSTRACT FROM AUTHOR]