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Psychopath Signs and Symptoms

Psychopathic Personality Symptoms. The modern usage of the term psychopathy dates from Cleckley’s clinical descriptions. Two of the features, impulsivity and an absence of anxiety, have been the object of motivational hypotheses. Lykken demonstrated poor electrodermal conditioning and/or rapid extinction using electric shock as the unconditioned stimulus and proposed that the electrodermal hyporeactivity reflected low fear in anticipation of punishment. Further, he showed that, in a ‘‘mental maze’’ task, psychopaths failed to avoid a punished incorrect alternative as well as controls.

Poor performance on this passive avoidance task (an analog impulsivity task) was also attributed to poor fear conditioning. Both findings have been conceptually replicated many times. After replicating the poor conditioning, Hare introduced a ‘‘countdown’’ to punishment task that also reliably shows electrodermal hyporeactivity in psychopaths in the few seconds before the delivery of punishment. All reviewers have found that electrodermal hyporeactivity in anticipation of punishment is a reliable finding. Similarly, the passive avoidance deficit has been demonstrated many times in psychopaths and in conduct disordered children who are low in anxiety. Recent interpretations of Lykken’s low fear hypothesis have employed Gray’s model to propose that psychopaths have a weak BIS and a normal (or strong) BAS. This hypothesis accounts for the disinhibitory psychopathology and lack of anxiety seen in psychopaths clinically—both central components of the BIS. Normal reward learning and active avoidance of punishment is consistent with a normal (or strong) BAS. In contrast to the electrodermal data, heart rate responses in paradigms that involve punishment do not show hyporeactivity in psychopaths and may even be larger than in controls.  

To account for this directional fractionation of electrodermal and cardiovascular reactivity, Fowles  proposed that electrodermal activity in response to threats of punishment may reflect BIS activity, whereas heart rate more strongly reflects somatic activity and activation of the BAS. Alternative biological hypotheses are also prominent in the literature. For example, Hare  reviews an extensive literature that suggests a broader range of neurobiological anomalies than can be subsumed under the low fear hypothesis. In a similar vein, Patrick and Lang propose that, in addition to a primary fear deficit, psychopaths show a deficit in higher information processing systems that interact with motivational systems. Resolving these issues is beyond the scope of this chapter, but it is clear that (1) Gray’s motivational concepts have been prominent in theories of the deficit associated with psychopathy and (2) alternative theories also refer to neurobiological processes.

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