Fleming SM, Weil RS, Nagy Z, Dolan RJ, Rees G. Relating Introspective Accuracy to Individual Differences in Brain Structure. Science, 329:1541-1543 (September 17, 2010).
From the abstract:
The ability to introspect about self-performance is key to human subjective experience, but the neuroanatomical basis of this ability is unknown. Such accurate introspection requires discriminating correct decisions from incorrect ones, a capacity that varies substantially across individuals. We dissociated variation in introspective ability from objective performance in a simple perceptual-decision task, allowing us to determine whether this interindividual variability was associated with a distinct neural basis. We show that introspective ability is correlated with gray matter volume in the anterior prefrontal cortex, a region that shows marked evolutionary development in humans. Moreover, interindividual variation in introspective ability is also correlated with white-matter microstructure connected with this area of the prefrontal cortex. Our findings point to a focal neuroanatomical substrate for introspective ability, a substrate distinct from that supporting primary perception.
Previously, we speculated that it was a cavern in the mid-brain (cavum septum pellucidum) that resulted in a lack of introspective ability, mostly because this would disconnect the areas for self-awareness (in the frontal cortex) with other brain areas.
The University College London group now quantifies the gray matter of those who aren’t good judges of their own abilities, and reports that they have less gray matter in a particular region in the frontal cortex, the anterior prefrontal cortex. They report that having trouble with introspection may correlate with frayed white matter (microstructure instability) connecting this area of introspection with other areas in the brain.
I wonder if this has to do with psychosis — or having a psychotic break. If you’ve ever been around someone who has no self doubt, who is a die-hard believer in . . .whatever, it’s creepy. They will continue with their belief without self doubt in the face of objective fact otherwise. From the outside it really looks like a delusion of some sort. I always thought it was simply shame, embarrassment, a power play, denial, whatever social maneuvering, but now I realize that this could be organic gray matter deficit and white matter microstructure impairment. This is especially creepy being around someone who is having a paranoia attack, and not just my own free floating version, but the psychotic-break kind.
On the other side of the coin are those who fake self doubt, which is also equally as creepy.
It is interesting that the part of the brain associated with introspection is that which shows the most recent evolutionary advancement. There’s something big about this but I don’t have the insight to figure it all out right now.
See previous posts on those with lack of introspection: