Procyk, E. | Search bioRxiv

bioRxiv2019

Investigating Confidence Judgments using Reviews in Human and Monkeys

Confidence judgments are self-assessments of the quality of ones own performance, and are a crucial aspect of metacognitive abilities. The underlying neurobiological mechanisms are poorly understood. One approach to understanding these mechanisms would be to take advantage of putative metacognitive abilities in non-human models. However, many discrepancies exist between human and non-human studies on metacognition due to the mode of reporting judgements. We here present an attempt to directly compare human and non-human primates metacognitive abilities using a protocol assessing confidence judgments. After performing a categorization test, subjects could either validate their choice or review the test. We could assess whether subjects detected their errors and how they corrected them according to their confidence, and importantly did so in both human and non-human primates. 14 humans and 2 macaque monkeys were tested. Humans showed a well-adapted use of the review option by reviewing more after incorrect choices or difficult stimuli. Non-human primates did not demonstrate a convincing use of the review or validate opportunity. In both species, reviewing did not improve performance. This study shows that decisions to review under uncertainty are not naturally beneficial to performance and is rather perturbed by biases and alternative low-cognitive cost strategies.

neuroscience↗

bioRxiv2019

Sulcal organization in the medial frontal cortex reveals insights into primate brain evolution

Although the relative expansion of the frontal cortex in primate evolution is generally accepted, the nature of the human uniqueness, if any, and between-species anatomo-functional comparisons of the frontal areas remain controversial. To provide a novel interpretation of the evolution of primate brains, sulcal morphological variability of the medial frontal cortex was assessed in old-world monkeys (macaque, baboon) and Hominoidea (chimpanzee, human). We discovered that both Hominoidea do possess a paracingulate sulcus, which was previously thought to be uniquely human and linked to higher cognitive functions like mentalizing. Also, we revealed systematic sulcal morphological organisations of the medial frontal cortex that can be traced from multiple old-world monkey to Hominoidea species, demonstrating an evolutionary conserved organizational principle. Our data provide a new framework to compare sulcal morphology, cytoarchitectonic areal distribution, connectivity, and function across the primate order, leading to clear predictions on how other primate brains might be anatomo-functionally organized.

neuroscience↗