Ability for introspection linked to brain biology

British scientists believe they have found the biological explanation for why some people are better than others at the important facility of introspection.

Researchers at the Institute of Cognitive Neuroscience and Wellcome Trust Centre for Neuroimaging at University College London (UCL) collected data from 32 subjects who were asked first to nominate which of two computer screens was the brightest. Then, more importantly, they were asked to rate how confident they were of their responses.

MRI scans of those subjects who demonstrated the higher levels of introspection revealed important biological differences around the front of the brain.

"We found a correlation between introspective ability and the structure of a small area of prefrontal cortex near the front of the brain," explained study leader Professor Geraint Rees from UCL.

"The better a person was at introspection, the more grey matter they had in this area. The same was true for the white matter or nerve connections in this area.

It is difficult, however, to know whether this difference is responsible for the varying levels of introspection discerned amongst the subjects, or whether a pre-existing ability could in fact be the cause of it.

"At this stage, we don't know why their grey or white matter differs in this small area,” professor Rees added. “Does this area develop as we get better at reflecting on our thoughts, or are people better at introspection if their prefrontal cortex is more developed in the first place?"

Nevertheless, the study’s findings have important implications for improving our understanding of thinking and the brain.

One of the biggest challenges faced by mental health professionals is treating patients who don’t appear to understand that they have a problem. The development of procedures which aid their ability to apply introspection could a herald a major step-change in the treatment of the mentally ill.

This research was funded by Wellcome Trust, the UCL Four-year PhD Programme in Neuroscience and the Medical Research Council.