The brain can be a good multitasker, using the same systems for unrelated functions. For example, the sensorimotor system may be used for imagining objects and concepts. What’s more, when one part of the brain fails to do is job, another part can sometimes fill in the gaps.
Yet some disorders do cause intractable problems. People with autism, for example, have difficulty recognizing personality traits in others. While the specific neurological cause of autism has yet to be isolated, one hypothesis suggests that the key is an inability to develop episodic memory. If you can’t recall the specific behaviors of an individual, then you’re not going to be very good at predicting their future behaviors.
People with autism can learn workarounds for this problem: they can attempt to catalog emotions in the same way they catalog other bits of knowledge, like state capitols. Generally, however, this strategy isn’t nearly as effective as the natural emotional processing in normal individuals.
Personality researchers have identified a mechanism for personality assessment: People have a database of personality trait summaries for people they know (Mom is kind, Dad is forgiving). These memories can be accessed 5 to 6 seconds faster than episodic memories. When a trait summary is accessed, it also activates episodic memories that are inconsistent with the trait (when Mom didn’t help my sister after she tripped; when Dad stopped speaking to his brother). This is useful, because it alerts us to the type of situation when the trait summary might not be valid. Consistent episodic memories need not be accessed, since the summary will suffice in those situations.
Since people with autism have difficulty accessing episodic memories, they aren’t able to assess personalities of others as effectively as normal individuals.
But what about accessing information about our own personalities? Logic might suggest that we use the same mechanism for ourselves as we do with others. If that’s the case, a research team led by Stanley Klein reasoned, then people who have had autism for their entire lives should also be unable to accurately describe their own personalities.
Klein’s group has worked extensively with a patient with autism, who they identify with the initials “R.J.” R.J. is a 21-year-old male, mildly retarded, with a mental age of 12. The team gave R.J. and his family personality tests where they rated themselves and the other members of their family on 26 personality traits. When R.J.’s ratings of himself were compared with his mother’s ratings of his personality, they were significantly correlated (r=.56), and that correlation didn’t differ from normal individuals’ self-ratings and mother’s ratings (see this site for an explanation of correlation).
At first glance, it appeared that R.J.’s ratings of his family’s personality traits were also accurate. The correlation between his ratings of his mother and his mother’s self-ratings was also significant (r=.59), as were his ratings and his father’s self-ratings (r=.52) and his ratings and his brother’s self-ratings (r=.48). A closer analysis, however, revealed a different story. R.J. didn’t differentiate between the personality traits of his mother, father and brother. He gave them identical ratings on 17 out of the 26 traits tested. The correlation between his ratings of his mother and father was r=.89. By contrast, the correlation between his self-ratings and his ratings of his mother was a more modest r=.42.
Klein’s team also tested a normal boy (“T.M.”) with the same mental age as R.J. While T.M.’s ratings of his parents correlated with their self-ratings at about the same level as R.J., he differentiated their personalities much more than R.J.: his rating of his mother and father was correlated at r=.52, significantly lower than R.J.’s r=.89.
Klein et al. argue that while R.J. has an accurate representation of his own personality, he is using stereotypes to represent the personalities of even his closest family members. So while R.J.’s case supports the hypothesis that autistic people are unable to form a database of personality traits for others, it suggests that there may be a different mechanism for forming awareness of our own personalities.
Although R.J.’s autism prevents him from forming accurate assessments of others, it appears that either he has managed to work around the limitations of his disorder to form a good picture of his own personality, or that all humans have two mechanisms for learning about personality traits: one for ourselves, and another for others.
Klein, S.B., Cosmides, L., Murray, E.R., & Tooby, J. (2004). on the acquisition of knowledge about personality traits: Does learning about the self engage different mechanisms than learning about others? Social Cognition, 22(4), 367-390.