Effects of caffeine on the trigeminal blink reflex

The acoustic startle and trigeminal blink reflexes share the same motor output. Since caffeine has been shown to augment the startle reflex, it was proposed that caffeine would also increase the trigeminal blink reflex. In 6 humans, the effects of caffeine (100 mg) on the trigeminal blink reflex were investigated. Reflex blinks were elicited by stimulation of the supraorbital branch of the trigeminal nerve. Following ingestion of caffeinated coffee, reflex blinks increased in amplitude and duration and occurred at a shorter latency than reflex blinks following ingestion of decaffeinated coffee. Since the blink reflex is a brainstem reflex, these results suggest that the psychomotor effects of caffeine facilitate brainstem processing.     

Contagious yawning and psychopathy

Psychopathy is characterized by a general antisocial lifestyle with behaviors including being selfish, manipulative, impulsive, fearless, callous, possibly domineering, and particularly lacking in empathy. Contagious yawning in our species has been strongly linked to empathy. We exposed 135 students, male and female, who completed the Psychopathic Personality Inventory-Revised (PPI-R), to a yawning paradigm intended to induce a reactionary yawn. Further, we exposed males to an emotion-related startle paradigm meant to assess peripheral amygdalar reactivity. We found that scores on the PPI-R subscale Coldheartedness significantly predicted a reduced chance of yawning. Further, we found that emotion-related startle amplitudes were predictive of frequency of contagious yawning. These data suggest that psychopathic traits may be related to the empathic nature of contagious yawning in our species.     

Psychopathy, aggression, and the processing of emotional stimuli in non-referred girls and boys

Research shows that individuals with psychopathic traits differ in how they process negative emotional stimuli. However, it is unclear whether these differences are specific to certain types of negative emotional stimulus and whether they are more strongly associated with psychopathic traits or aggression. Further, it is not clear whether or not deficits in emotional processing generalize to females and ethnic minority individuals with psychopathic traits. In this study, we examined the emotional processing of visual stimuli using a dot-probe task in 50 non-referred girls and boys (mean age of 9.30; SD = 2.00). Overall, there was a significant association between proactive aggression and reduced responsiveness to distressing stimuli. In addition, the predicted association between psychopathic traits and reduced responsiveness to distressing stimuli was only found for children high on aggression. Also, the associations among aggression, psychopathic traits, and responsiveness to distressing stimuli did not differ for boys and girls.     

Clarifying the role of defensive reactivity deficits in psychopathy and antisocial personality using startle reflex methodology

Prior research has demonstrated deficits in defensive reactivity (indexed by potentiation of the startle blink reflex) in psychopathic individuals. However, the basis of this association remains unclear, as diagnostic criteria for psychopathy encompass two distinct phenotypic components that may reflect differing neurobiological mechanisms-an affective-interpersonal component and an antisocial deviance component. Likewise, the role of defensive response deficits in antisocial personality disorder (APD), a related but distinct syndrome, remains to be clarified. In the current study, the authors examined affective priming deficits in relation to factors of psychopathy and symptoms of APD using startle reflex methods in 108 adult male prisoners. Deficits in blink reflex potentiation during aversive picture viewing were found in relation to the affective-interpersonal (Factor 1) component of psychopathy, and to a lesser extent in relation to the antisocial deviance (Factor 2) component of psychopathy and symptoms of APD-but only as a function of their overlap with affective-interpersonal features of psychopathy. These findings provide clear evidence that deficits in defensive reactivity are linked specifically to the affective-interpersonal features of psychopathy and not to the antisocial deviance features represented most strongly in APD.     

Acoustic startle in maltreated children

We investigated the eyeblink component of acoustic startle reactions in maltreated children. Previous research indicates that acoustic startle is enhanced in adult males with posttraumatic stress disorders (PTSD) whereas findings on women with PTSD have been inconsistent. In accord with the only previous report for children with PTSD, we found that maltreated boys, particularly those who had been physically abused, responded to increases in startle probe loudness with smaller increments in amplitude of startle eyeblink and smaller reductions in blink latency than did comparison boys. Results for girls were inconsistent: younger maltreated girls had smaller startle amplitude and slower onset latency than controls, whereas older maltreated girls exhibited the opposite pattern.     

Stability and predictors of psychopathic traits from mid‐adolescence through early adulthood

High levels of psychopathic traits in youth are associated with multiple negative outcomes including substance misuse, aggressive behavior, and criminality. Evidence regarding stability of psychopathic traits is contradictory. No previous study has examined long‐term stability of psychopathic traits assessed with validated clinical measures. The present study examined the stability of psychopathic traits from mid‐adolescence to early adulthood and explored adolescent factors that predicted psychopathic traits five years later. The sample included 99 women and 81 men who had consulted a clinic for substance misuse in adolescence. At an average age of 16.8 years, the adolescents were assessed using the Psychopathy Checklist: Youth Version (PCL: YV) and five years later using the PCL‐Revised (PCL‐R). Additionally, extensive clinical assessments of the adolescents and their parents were completed in mid‐adolescence. Among both females and males, moderate to high rank‐order stability was observed for total PCL and facet scores. Among both females and males, there was a decrease in the mean total PCL score, interpersonal facet score, affective facet score, and lifestyle facet score. However, the great majority of females and males showed no change in psychopathy scores over the five‐year period as indicated by the Reliable Change Index. Despite the measures of multiple family and individual factors in adolescence, only aggressive behavior and male sex predicted PCL‐R total scores in early adulthood after taking account of PCL:YV scores. Taken together, these results from a sample who engaged in antisocial behavior in adolescence suggest that factors promoting high psychopathy scores act early in life.     

Empathy,morality and psychopathic traits in women

Empathic and moral processing correlates of psychopathic personality have seldom been studied in women. In this study, we experimentally tested associations between psychopathic personality traits and empathic and moral processing in a female sample, and further directly compared them to results from a male sample. We found that high levels of affective-interpersonal traits were associated with diminished affective response to sad and fearful emotions in others; lower propensity to feel moral emotions; higher endorsement of utilitarian solutions to moral dilemmas involving direct harm; and less self-reported difficulty when performing moral decision making. Overall, our findings strengthen the view that the two dimensions of psychopathy make distinct contributions to emotional and moral processing; and demonstrate that, in women, psychopathic personality traits are associated with a similar pattern of empathic and moral processing biases as the one that has been previously reported in men.     

Paralimbic Gray Matter Reductions in Incarcerated Adolescent Females with Psychopathic Traits

Psychopathy-related paralimbic and limbic structural brain abnormalities have been implicated in incarcerated adult and adolescent male samples. However, there have been few neuroimaging studies of psychopathic traits in females in general and no studies from incarcerated female youth in particular. Here we present the first study to examine the relationship between brain gray matter volumes and psychopathic traits (assessed using the Psychopathy Checklist-Youth Version [PCL-YV]) in a sample of maximum-security incarcerated female adolescents (N?=?39; mean age?=?17.6 years). Consistent with male samples, regional gray matter volumes were negatively related to psychopathic traits in female youth offenders in limbic and paralimbic areas, including orbitofrontal cortex, parahippocampal cortex, temporal poles, and left hippocampus. These results provide evidence that psychopathic traits manifest similar neural abnormalities across sex and age.     

Cross-modal attention capture by affective stimuli: Evidence from event-related potentials

The P3 component of the event-related potential (ERP) to an acoustic startle probe is modulated during picture viewing, with reduced P3 amplitude when participants view either pleasant or unpleasant, as opposed to neutral, pictures. We have interpreted this as reflecting capture of attentional resources by affective pictures, with fewer resources available for processing the secondary startle probe. In the present study, we tested this resource allocation hypothesis by presenting either pictures or sounds as foreground stimuli, with the prediction that P3 amplitude in response to secondary startle probes would be reduced for affectively engaging foregrounds regardless of modality. Using dense-array electroencephalography and a source estimation procedure, we observed that P3 amplitude was indeed smaller when startle probes were presented during emotional, as opposed to neutral, stimuli for both sound and picture foregrounds. Source modeling indicated a common frontocentral maximum of P3 modulation by affect. The data support the notion that emotionally arousing stimuli transmodally attract resources, leading to optimized processing of the affective stimuli at the cost of the processing of concurrent stimuli.     

Inhibition of acoustic startle using different mechanoreceptive channels

In this experiment, we investigated the impact of vibrotactile prepulse frequency and intensity on the acoustically elicited startle response in humans. Mechanoreceptive channels differing in their sensitivity to transient stimulation have been identified in the skin. The Pacinian channel is optimally sensitive to vibrations at approximately 300 Hz and is specialized for the detection of stimulus transients, whereas the non-Pacinian I and III channels are optimally sensitive to vibrations at approximately 30 Hz. Vibrotactile prepulses with frequencies of 30 and 300 Hz and intensities of 95 and 130 mV were presented for 50 msec to the dominant hand of college students (N = 31), followed on some trials by a 95-dB broadband acoustic startle stimulus. The 300-Hz prepulses resulted in significantly more pronounced inhibition of startle magnitude, amplitude, and probability, whereas only the 30-Hz prepulses significantly facilitated blink latency. These results support the idea that the inhibition of acoustic startle is determined more by transient than by sustained aspects of vibrotactile prepulse stimuli. This study also demonstrates that different aspects of the startle response differentially reflect stimulus characteristics of the prepulse.     

Startle modulation in non-incarcerated men and women with psychopathic traits

Past research has demonstrated that individuals with psychopathic characteristics are under-responsive to aversive stimuli, however, much of this work has failed to include non-incarcerated samples, or to examine gender differences in this relationship. Additionally, few studies have examined the role of specific personality characteristics, as they relate to both psychopathic behavior and emotional responsiveness. The current study assessed emotional modulation of the startle response in a community sample of 108 men and women (99 with usable startle data) during perception of emotion-laden photographs. Consistent with previous work, men reporting high levels of psychopathy failed to show the typical increase in the startle response when exposed to aversive photographs, but only when responses were elicited relatively early in picture viewing (i.e., 2.0 s as compared to 4.5 s post-photograph onset). Additionally, both genders showed a significant effect of harm avoidance and anxiety on modulation of the startle response, such that individuals reporting low levels of each trait failed to show significant responses to aversive photographs. These results suggest that while deficits in emotional processing extend to non-incarcerated samples, the relationship may be influenced by additional factors including gender, personality, and attributes related to incarceration.     

Interaction between Prenatal Maternal Stress and Autonomic Arousal in Predicting Conduct Problems and Psychopathic Traits in Children

Evidence has suggested that neurobiological deficits combine with psychosocial risk factors to impact on the development of antisocial behavior. The current study concentrated on the interplay of prenatal maternal stress and autonomic arousal in predicting antisocial behavior and psychopathic traits. Prenatal maternal stress was assessed by caregiver’s retrospective report, and resting heart rate and respiratory sinus arrhythmia (RSA) were measured in 295 8- to 10-year-old children. Child and caregiver also reported on child’s antisocial behavior and psychopathic traits. Higher prenatal maternal stress was associated with higher caregiver-reported antisocial and psychopathy scores, even after the concurrent measure of social adversity was controlled for. As expected, low heart rate and high RSA were associated with high antisocial and psychopathic traits. More importantly, significant interaction effects were found; prenatal stress was positively associated with multiple dimensions of psychopathic traits only on the conditions of low arousal (e.g., low heart rate or high RSA). Findings provide further support for a biosocial perspective of antisocial and psychopathic traits, and illustrate the importance of integrating biological with psychosocial measures to fully understand the etiology of behavioral problems.     

Conceptualizing psychopathic traits from an evolutionary-based perspective: An empirical study in a community sample of boys and girls

Although psychopathy has historically been associated with a lack of emotion, recent research has suggested that psychopathy may represent a tendency to externalize the experience of unpleasant emotions, including shame, which could be seen as an adaptive strategy within an evolutionary framework. However, more empirical research is needed to build on this argument. This study tested a novel evolutionary-based model involving pathways associating the impact of harsh rearing experiences (warmth and safeness experiences and traumatic shameful experiences) with psychopathic traits as well as the indirect effects of external shame and shame coping strategies in this association. This study also tested the invariance of this model across gender. A youth community sample (N = 703; 58.9% girls) completed self-report questionnaires on the impact of harsh rearing experiences, external shame, shame coping strategies, and psychopathic traits. The results suggested that the impact of harsh rearing experiences was directly and indirectly (through external shame and shame coping strategies) associated with psychopathic traits. The model partially explained the endorsement of psychopathic traits in boys and girls, although gender differences were found in some of the pathways. These findings offer support for conceptualizing psychopathic traits as an adaptive strategy to cope with the impact of harsh rearing experiences, opening new perspectives for prevention and treatment.

     

Psychopathic Traits and Physiological Responses to Aversive Stimuli in Children Aged 9–11 Years

Atypical eletrodermal and cardiovascular response patterns in psychopathic individuals are thought to be biological indicators of fearless and disinhibition. This study investigated the relationship between psychopathic traits and these autonomic response patterns using a countdown task in 843 children (aged 9-10?years). Heart rate (HR) and non-specific skin conductance responses (NS-SCRs) were recorded while participants anticipated and reacted to 105?dB signaled or un-signaled white-noise bursts. Using multilevel regression models, both larger HR acceleration and fewer NS-SCR were found to be significantly associated with psychopathic traits during anticipation of signaled white-noise bursts. However, two divergent patterns appeared for HR and SCR: (1) larger HR acceleration was specific to the callousness-disinhibition factor of psychopathic traits while reduced NS-SCR was only associated with the manipulative-deceitfulness factor; (2) the negative association between the manipulative-deceitfulness factor and NS-SCR was only found in boys but not in girls. These findings replicated what has been found in psychopathic adults, suggesting that autonomic deficits present in children at risk may predispose them to later psychopathy. The divergent findings across psychopathic facets and sexes raised the possibility of different etiologies underlying psychopathy, which may in turn suggest multiple treatment strategies for boys and girls.     

Self-report and startle-based measures of emotional reactions to body image cues as predictors of Drive for Thinness and Body Dissatisfaction in female college students

The purpose was to compare self-report and psychophysiological assessment techniques in the measurement of emotional response to body image cues. Female college students (n=53; % Caucasian=53.6; M body mass index=26.1 kg/m2) completed the Eating Disorder Inventory (EDI-3) and viewed photos of themselves both unaltered and morphed to simulate weight gain. Response to the photos was assessed by self-report and the affect modulated startle paradigm. EDI-3 Drive for Thinness (DT) and Body Dissatisfaction (BD) scale scores were correlated with startled amplitude for the largest simulated weight gain photo. Startle eye blink amplitude predicted more variance in DT and BD subscales than self-reported response to the image. The affect modulated startle paradigm may provide unique information in the assessment of eating disorder symptomatology that cannot be captured via self-report techniques, and has potential to inform evaluation of treatment outcomes of eating and body image disorders.     

Facial emotion recognition,guilt and sub-clinical psychopathic traits: an exploration of mediation effects

Psychopathic traits are associated with a variety of emotional difficulties, including poor facial emotion recognition (FER) and reduced capacity to experience guilt. However, the potential mechanisms through which FER and low guilt-proneness are related to the development of psychopathic traits are not well understood. Using a non-clinical sample (N?=?747), this study investigated the relationship between psychopathic traits, FER ability and guilt-proneness by exploring two alternative mediation models investigating: (a) the mediating effect of FER ability on the relationship between psychopathic traits and guilt-proneness, and (b) the mediating effect of psychopathic traits on the relationship between FER ability and guilt-proneness. FER ability did not significantly mediate the relationship between psychopathic traits and guilt-proneness. However, psychopathic traits did partially mediate the relationship between FER and guilt-proneness for the sad, angry, fearful and disgusted expressions. These findings suggest that psychopathic traits are related to a disruption in typical affective processing and the development of pro-social moral self-conscious emotions.     

Startle modulation in non-incarcerated men and women with psychopathic traits

Past research has demonstrated that individuals with psychopathic characteristics are under-responsive to aversive stimuli, however, much of this work has failed to include non-incarcerated samples, or to examine gender differences in this relationship. Additionally, few studies have examined the role of specific personality characteristics, as they relate to both psychopathic behavior and emotional responsiveness. The current study assessed emotional modulation of the startle response in a community sample of 108 men and women (99 with usable startle data) during perception of emotion-laden photographs. Consistent with previous work, men reporting high levels of psychopathy failed to show the typical increase in the startle response when exposed to aversive photographs, but only when responses were elicited relatively early in picture viewing (i.e., 2.0 s as compared to 4.5 s post-photograph onset). Additionally, both genders showed a significant effect of harm avoidance and anxiety on modulation of the startle response, such that individuals reporting low levels of each trait failed to show significant responses to aversive photographs. These results suggest that while deficits in emotional processing extend to non-incarcerated samples, the relationship may be influenced by additional factors including gender, personality, and attributes related to incarceration.     

Psychopathic traits and externalizing behaviors: a comparison of self- and informant reports in the statistical prediction of externalizing behaviors

It has long been assumed that features associated with psychopathy, such as a lack of insight and deceitfulness, may compromise the utility of self-report measures, particularly for understanding the relations between these traits and important outcomes (e.g., offending). Unfortunately, little research has explicitly examined the relations between self- and informant reports of psychopathy and their relations to these outcomes. The current study examined the incremental validity of self- and informant reports of psychopathic traits, assessed with 3 validated psychopathy measures, in the statistical prediction of externalizing behaviors (EBs). To reduce shared method variance, self- and informant reports of EBs (i.e., substance use, antisocial behavior, gambling, and intimate partner violence) were examined separately. Results indicate that both self- and informant reports of psychopathy are related to EBs and provide some degree of incremental validity, although self-reported psychopathy scores proved slightly more useful than other-reported psychopathy scores. These findings suggest that, in nonforensic settings, psychopathy data derived from both self- and other-reported psychopathy measures have utility in understanding the relations between psychopathic traits and EBs.     

Psychopathic personality traits predict competitive wins and cooperative losses in negotiation

Corporate corruption has recently called attention to the relevance of psychopathic personality traits—the absence of conscience, remorse, or scruples—in business settings; yet, little is known about how these personality traits affect business practices. We present two studies testing whether psychopathic personality traits are related to social perspective and cognitive decision-making biases relevant to negotiation, and whether those traits affect outcomes in a negotiation simulation. Psychopathic personality features were associated with a competitive world-view, including selfish social motivations and illusions of conflict with others. In mixed-motive negotiations, psychopathic traits predicted greater personal monetary gains when success favored competitive actions, but predicted monetary loss when success depended on cooperation. Results suggest that psychopathic personality traits can both bolster and hinder success in business.     

Unique roles of antisocial personality disorder and psychopathic traits in distress tolerance

Previous research indicates that individuals with antisocial personality disorder (ASPD) evidence low distress tolerance, which signifies impaired ability to persist in goal-directed behavior during an aversive situation, and is associated with a variety of poor interpersonal and drug use outcomes. Based on theory and research indicating that psychopathic traits are associated with hypo-reactivity in emotional responding, a unique hypothesis emerges where psychopathic traits should have the opposite effect of ASPD and be related to high levels of distress tolerance. In a sample of 107 substance-dependent patients in an inner-city substance use residential treatment facility, this hypothesis was supported. ASPD was related to lower distress tolerance, while psychopathic traits were related to higher distress tolerance, with each contributing unique variance. Findings are discussed in relation to different presentations of distress tolerance as a function of psychopathic traits among those with an ASPD diagnosis.