Neuropsychology in psychopaths

It is suggested that there are several executive function deficits in psychopatic individuals (Snowden, Gray, Pugh, and Atkinson, (2013). Participants scoring high on psychopathy in a student population were found to be deficient in OFC function tasks. They were impaired on the object alternation task, especially with respect to the Fearless Dominance Scale of the PPI-R. Furthermore, the scales of the PPI-revised were associated with both Fearless Dominance as well as with Self-Centered Impulsivity on the Porteus Maze task (Snowden et al., 2013).

Pham, Vanderstukken, Philippot, and Vanderlinden (2003) investigated whether criminal psychopatic individuals show impairments in selective attention and executive functions. Several tests were administered. The D-II  cancellation task assesses selective attention and scanning ability. The Porteus Maze Test assesses the capability to plan and to keep a pattern of responses in case participants are confronted with interference. The Tower of London Test measures the ability of planning. The Stroop Color Word Interference Test measures interference and maintainance of a response pattern. The Trail Making Test is a response alternation test. Finally, the Modified Wisconsin Card Sorting Test assesses the capabilities and the flexibility of cognitive sets (Pham et al., 2003). On the D-II task the psychopatic individuals did commit more errors as compared to control subjects. In addition, they were deficient in their attentional maintenance. On the Porteus Maze Test, psychopatic individuals did not make more errors of quantitative origin than control subjects. But they made more quantitative errors and had more difficulty as compared to control subjects in maintaining their course. On the Tower of London Test, psychopaths had no longer initiation times and they did not exhibit more rule breaking as compared to control subjects. It is suggested that the findings on the Porteus Maze Test and Tower of London test are not indicative of a global planning deficit in psychopatic individuals (Pham et al., 2003). On the Stroop Test, the psychopaths did not make more errors to distracting cues as well as no inability in inhibiting interference. It is further argued that psychopatic individuals have an impairment in attentional control when they are exposed to stimuli that are distracting, as revealed by making more excessive movements when they were given a misleading situation on the Tower of London Test. It is concluded that psychopaths are especially deficient during tasks considering planning abilities that need behavioral inhibition. On the Trail Making Test and the Modified WCST psychopatic individuals did not differ from control subjects (Pham et al., 2003).

In another study, selective attention was investigated in psychopatic individuals with three different Stroop Tests. These were the standard Color Word Stroop Test, a picture word Stroop test and a color word Stroop test in which the color and word were separated spatially (Hiatt, Schmitt, and Newman, 2004). Psychopatic individuals were found to be not impaired on the standard Stroop Test. However, they showed impairments on both of the other Stroop Tests. It is suggested that psychopatic individuals are not deficient in the case when incongruent contextual information is given whithin their direct focus of attention. However they show impairments when not directly in their attentional focus as revealed by the other two Stroop tests (Hiatt et al., 2004).

Psychopatic individuals performed a CPT. Response latency was assessed after given feedback (Molto et al., 2007). Perseverative behavior in psychopatic individuals was only associated with factor 2 of the PCL-R, especially related to impulsive and irresponsible lifestyle aspects. Response perseveration was found to be associated with a lack of reflection after punishment as well as after reward feedback. All participants in the experiment played more cards what was found as evidence for response perseveration and the group collected as a result lower earnings. Both, after punishment and reward feedback on the CPT an association of shorter pauses between trials was found. It is suggested that response perseveration impairments found in psychopatic individuals might not be only related to the syndrome, rather it might generally be associated with externalizing behavior, which shows an overlap with social deviance in psychopathy (Molto et al., 2007).

Psychopatic and non-psychopatic inmates performed a simultaneously visual and auditory task under the condition of focussing their attention at the visual primary task. The psychopatic inmates did respond to distractor stimuli after targets with a higher intensity which is suggested to be the result of diminished attention payed to the peripheral dimension of two-dimensional stimuli (Kosson, 1996).