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DO PSYCHOPATHS' BRAINS FAIL TO UNDERSTAND THE ABSTRACT?
Psychopaths are callous, glib, superficial, and impulsive; lack
empathy for others; and display no guilt or remorse for their harmful
acts. One reason for these traits, research suggests, is that psychopaths
have difficulty understanding emotions. However, a new study indicates
that psychopaths are impaired not just in the emotional realm, but more
broadly, in understanding abstract information in general.
Kent Kiehl, Robert Hare, and colleagues studied eight male criminal
psychopaths, all inmates of a maximum-security prison in Canada,
comparing them to eight non-criminal, non-psychopathic controls. The
researchers controlled for a wide range of factors including age, parental
socioeconomic status, education level, and IQ.
The subjects participated in a test in which they viewed concrete
words (such as "table"), abstract words (such as "justice"), and pseudo-
words. All words were selected to be emotionally neutral to eliminate
emotional response as a factor. Subjects viewed word groups containing
either concrete words and similar-looking pseudo-words, or abstract
words and similar-looking pseudo-words. They were instructed to raise
one hand each time a real word appeared, and to raise the other hand if a
pseudo-word appeared. During the tests, the researchers investigated
brain changes in the participants using functional magnetic resonance
imaging (fMRI).
Psychopathic subjects, Kiehl et al. say, "performed more poorly,
manifested as slower reaction times, than control participants, when
processing abstract word stimuli." This is consistent, they say, with
studies showing that psychopaths have trouble processing abstract words,
performing abstract categorization tasks, understanding metaphors, and
processing emotionally weighted words and speech.
In particular, the psychopaths showed clear deficits in activating one
brain area, the right anterior superior temporal gyrus, when processing
abstract stimuli. This region failed to differentiate normally between
abstract and concrete stimuli.
The researchers say, "These data support the hypothesis that there is
an abnormality in the function of the right anterior superior temporal
gyrus in psychopathy."
"Perhaps," the researchers say, "psychopathic individuals have
difficulty engaging in cognitive functions that involve material that has
no concrete realization in the external world. We might speculate that
complex social emotions such as love, empathy, guilt and remorse may
be a form of more abstract functioning. Thus, difficulties in processing
and integrating these conceptually abstract representations to regulate or
modulate behavior would be [seen] in these individuals."
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"Temporal lobe abnormalities in semantic processing by criminal
psychopaths as revealed by functional magnetic resonance imaging,"
Kent A. Kiehl, Andra M. Smith, Adrianna Mendrek, Bruce B. Forster,
Robert D. Hare, and Peter F. Liddle, Psychiatry Research:
Neuroimaging, Vol. 130, 2004, 27-42. Address: Kent A. Kiehl,
kent.kiehl@yale.edu.
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