New research published in the Sept. 17th issue of Science reports that people with a higher volume of gray matter, and high-integrity white matter, are able to better self-judge the merits of their decisions. Gray matter, located in the anterior prefrontal cortex region, or the outer layer of the brain right behind the eyes, has been previously linked to assessments of decision-making. Now however, study researcher and neuroscientist Stephen Fleming at the Wellcome Trust Centre for Neuroimaging at the University College London believes the results show a direct correlation to introspection and brain structure. In the study, 32 subjects were given a series of choices, and after every choice were asked to rate their confidence in the decision. The researchers found that the ability to judge decisions ranged quite widely among volunteers, but by using images of the subject’s brains, they were able to establish a relationship between features of gray and white matter and metacognitive ability. It is still unclear whether anatomical differences are the result of learning and experience, or are innate, but the researchers believe being able to assess decisions may prove to be an important part of consciousness as well as lead to a greater understanding of how the brain is aware of its own mental states.