Attention moderates the fearlessness of psychopathic offenders

Abstract

Background: Psychopathic behavior is generally attributed to a fundamental, amygdala-mediated deficit in fearlessness that undermines social conformity. An alternative view is that psychopathy involves an attention-related deficit that undermines the processing of peripheral information, including fear stimuli.

Methods: We evaluated these alternative hypotheses by measuring fear-potentiated startle (FPS) in a group of 125 prisoners under experimental conditions that 1) focused attention directly on fear-relevant information or 2) established an alternative attentional focus. Psychopathy was assessed using Hare's Psychopathy Checklist-Revised (PCL-R).

Results: Psychopathic individuals displayed normal FPS under threat-focused conditions but manifested a significant deficit in FPS under alternative-focus conditions. Moreover, these findings were essentially unchanged when analyses employed the interpersonal/affective factor of the PCL-R instead of PCL-R total scores.

Conclusions: The results provide unprecedented evidence that higher-order cognitive processes moderate the fear deficits of psychopathic individuals. These findings suggest that psychopaths' diminished reactivity to fear stimuli, and emotion-related cues more generally, reflect idiosyncrasies in attention that limit their processing of peripheral information. Although psychopathic individuals are commonly described as cold-blooded predators who are unmotivated to change, the attentional dysfunction identified in this study supports an alternative interpretation of their chronic disinhibition and insensitive interpersonal style.

Figure 1. Schematic of Task and Fear-potentiated startle measurement

Panel A: Participants view a series of 400ms upper/lower case letter stimuli colored red/green. In all three conditions, electric shocks are administered after some red but not green letters. In threat-focused condition, participants respond (via two buttons) to indicate letter color. In alternative focus/low load, participants respond to indicate letter case. In alternative focus/high load, participants respond to indicate letter match between current letter and letter 2-back. White noise “startle probes” are presented following letter stimuli to measure fear-potentiated startle (FPS). Panel B: The eyeblink component of the startle reflex is measured via electromyographic (EMG) activity in the orbicularis oculi muscle. Raw blink EMG activity is elicited by 50ms startle probes during threat and no-threat trials. This raw signal is rectified and smoothed (30Hz low pass filter). FPS is calculated as the difference between peak EMG response on Threat vs. No-threat trials.

Figure 2. Fear-Potentiated Startle by Psychopathy and Condition

Focus of attention significantly moderated the Psychopathy effect on fear-potentiated startle (FPS). High Psychopathy prisoners displayed significantly lower FPS than low Psychopathy prisoners in the Alternative-focus conditions. High and low Psychopathy prisoners displayed comparable FPS in the Threat-focus condition. FPS was calculated as startle response during red/threat minus green/neutral letter trials. FPS means displayed for low and high Psychopathy were calculated at 1.5 standard deviations below and above the sample mean on Psychopathy total scores, respectively. Error bars represent the standard error for the point estimate.

Figure 3. Fear-Potentiated Startle by Factor 1 of the Psychopathy Checklist and Condition

Focus of attention significantly moderated the Factor 1 effect on fear-potentiated startle (FPS). High Factor 1 prisoners displayed significantly lower FPS than low Factor 1 prisoners in the Alternative-focus conditions. High and low Factor 1 prisoners displayed comparable FPS in the Threat-focus condition. FPS was calculated as startle response during red/threat minus green/neutral letter trials. FPS means displayed for low and high Factor 1 were calculated at 1.5 standard deviations below and above the sample mean on Factor 1 scores, respectively. Error bars represent the standard error for the point estimate.