Contributions of age and clinical depression to metacognitive performance

Background: Pivotal for adaptive behaviour is the ability to judge whether our performance is correct or not, even in the absence of external feedback. This metacognitive ability can be measured using confidence ratings. Past research suggests that overall confidence (confidence bias) is lower in Major Depressive Disorder (MDD). Less is known about the ability of MDD patients to discriminate correct from incorrect performance (metacognitive efficiency). Methods: The perceptual metacognitive performance of 17 aged MDD patients (62-89 years) was tested and compared to an age matched as well as a young control group (21-28 years). The younger control group was included to disentangle the effects of age and MDD on metacognitive performance. Indeed, earlier studies found an increased confidence bias but a decreased metacognitive efficiency with age. Results: Our results showed no difference in confidence bias nor in metacognitive efficiency between MDD patients and age-matched control participants. Importantly, aged participants, including both aged controls and MDD patients, demonstrated lower metacognitive efficiency compared to young participants. This metacognitive deficit found in aged participants was specifically driven by an overconfidence on incorrect trials. Conclusions: The relation between MDD and confidence bias may not be as robust as previously claimed. Furthermore, our results point to the importance of age rather than MDD for metacognitive efficiency. This could have important clinical implications as the observation of lower metacognitive abilities in patients is not necessarily caused by the depression. Limitations: Sample size was relatively small. Some clinical variables such as anxiety, or medication were not controlled.