Would you like to phone a friend? Scientists link introspection accuracy to brain structure
Thursday 16 September
A study funded by the Medical Research Council (MRC) has found that our ability to reflect on our thoughts, emotions and behaviour is linked to brain structure. The process, known as introspection, is one of the key aspects of consciousness and what makes us human, but its biological basis has until now been unknown. The researchers believe these results might help them understand why and how brain damage can affect a person’s ability to reflect on their thoughts, and to develop appropriate treatments in future.
The researchers from the Institute of Cognitive Neuroscience and Wellcome Trust Centre for Neuroimaging at University College London (UCL) found that the accuracy of introspection differed substantially amongst the 32 study participants. Using an MRI scanner, the researchers found the better a person was at introspection, the more grey and white matter and nerve connections they had in an area of the brain known as the prefrontal cortex, which plays a role in judgement and decision making.
There are no outward physical signs of introspective thought and therefore measuring it scientifically has previously proved challenging. For this study though, the researchers devised an experiment that could provide both an objective measure of a person’s performance at a task and also a measure of how well they could judge their own performance, or introspection.
Dr Rimona Weil, an MRC-funded scientist and joint first author on the paper, said:
“We made the task difficult so that people could never be entirely sure whether their answer was correct. Someone who is good at introspection will be confident when they know they are correct, but less confident when they are not sure. It’s a bit like 'Who wants to be a Millionaire?' – a person with good introspection will go with their answer when they’re sure, and phone a friend if unsure. But a poor contestant might not be as good at judging how likely they are to be correct."
The participants were briefly shown two screens. Each screen contained six patches; on one of the screens, one of the patches was brighter than the rest. They were asked to identify which screen contained the brighter patch, and then asked to rate how confident they were in their decision.
By funding research that underpins our knowledge of the brain at a structural level, the MRC aims to further understanding of brain processes and neurological conditions, which in turn will eventually help to establish treatments for patients with disorders ranging from brain damage to dementia. The MRC supported this research with a £207,000 fellowship grant.
The paper, Relating introspective accuracy to individual differences in brain structure, is published in the journal Science today and findings were announced at the British Science Festival in Birmingham. The research was funded by the Wellcome Trust, the UCL and the Medical Research Council.
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