Motivation and emotion/Book/2015/Psychopathy and emotion

Psychopathy and emotion:
What problems do psychopaths experience in processing and interpreting emotional stimuli?

Multimedia presentation (3 min)

Overview

Figure 1. A scared child expressing fear in an adverse situation.

Being social creatures, it is presumed that humans interpret the world in a similar context, understanding and experiencing a wide range of interchangeable emotions. Most people, for example, can comprehend the signs of fear in a person’s face: the eyes widen, the eyebrows arch upwards, and the mouth opens to gasp or scream. When we watch television, we often identify with the characters and resonate with their situation, processes which are seemingly automatic and unconscious to the everyday person.

However for a relatively small subset of the population, this is not the case. While most psychopaths may appear normal, charming or even charismatic, an abundance of research has found that they lack emotional re-activity and thus struggle to empathise with others, although they are quite capable of mimicking these emotions. In the field of psychology, these individuals have become an object of popular fascination and clinical anguish, particularly in terms of understanding and interpreting emotional stimuli. In light of these complexities, the following chapter explores the emotional processes underlying psychopathy.

Perennial questions within this chapter: What is psychopathy and how can it be measured? How do psychopaths differ in their emotional processing? What brain structures are implicated in these deficits? How can these abnormalities be practically and theoretically explained? What implications do these findings have for psychopaths?

About Psychopathy

Definition

Figure 2. When you think about the term 'psychopath', what comes to mind? A popular example in modern culture is the Joker from the hit movie franchise Batman.

In modern day society, the term psychopathy is often accompanied by mystery and controversy (Smith, Edens, Clark & Rulseh, 2014). Consistently portrayed as sadistic individuals within movies and social media, the term is usually associated with images of brutal killers like the Joker from Batman, or Christian Bale in American Psycho. However, does this stereotype represent a reality?

Despite a multitude of references to psychopathic personalities, researchers continue to debate the core features which may comprise the disorder. Quantitative literature has demonstrated that the main characteristics of psychopathy are remarkably diverse, involving a combination of interpersonal, behavioral, and affective traits (Cooke & Mitchie, 2001). Consequently, debates persist regarding how the construct is best conceptualized, and whether criminal or aggressive behaviour is essential in its classification (Marsh, 2013). Thus the definition of psychopathy is rather broad in nature, and due to this, the concept varies dramatically throughout psychological literature and research.

In its simplest form, psychopathy is a personality disorder characterized by shallow affect, lack of empathy, irresponsibility; impulsivity; and poor decision-making (Kiehl & Hoffman, 2011). The antisocial tendencies that accompany these traits include poor anger control, and an apathetic orientation towards others (Frick & Ellis, 1999). These factors are positively related, indicating that higher levels of callousness predict greater levels of antisocial behaviour (Kahn, Byrd & Pardini, 2013). Therefore, the presence of psychopathic traits is a strong determinant of aggression that typically serves an instrumental goal; including bullying, sexual violence or generalised crime (Woodworth & Porter, 2002).

Prevalence

No epidemiological research has directly quantified the prevalence rates of psychopathy across the general population (Viding, McCrory & Seara-Cardoso, 2014). However, empirical research suggests that less than 1% of all non-institutionalised adults satisfy the diagnostic criteria for psychopathy (Hart & Hare, 1996). Its prevalence in institutional settings however, does appear to be substantially higher, with an estimated 15-25% of incarcerated individuals meeting the criteria for the disorder (Viding et al., 2014). Findings also suggest that more males exhibit these traits than females, although the precise gender ratio is still dubious (Blair & Mitchell, 2009).

Measurement and Assessment

Although psychopathy has yet to be recognized as a specific personality disorder, a number of psychometric scales have been developed to measure the construct (Beech, 2015).

Hare Psychopath Checklist-Revised (PCL-R)

The Hare Psychopathy Checklist–Revised (1991) is a diagnostic tool used to standardise a person's psychopathic or antisocial dispositions. It is comprised of two parts; a semistructured interview, and an analysis of the subjects records and history (Hare et al.,1990). On the basis of these assessments, qualified professionals evaluate individuals on a 20-item test which measure the diagnostic symptoms or traits of a psychopathic personality (see Table 1). All of the items are summed up for a final score which conceptualizes the subjects resemblance to a prototypical psychopath (Cooke, Michie, Hare & Hart, 1999).

The PCL-R has received extensive attention from forensic researchers because of its predictive validity in the context of deviant behaviour. More specifically, it is a strong predictor of recidivism, violence and response to therapeutic intervention (Cooke et al., 1999). With demonstrated reliability and validity, it has rapidly been adopted as the go to instrument for all researchers and clinicians. Carrying a high level of academic consensus, it is the most dependable instrument for the assessment of psychopathy in criminal and non-criminal populations (Marsh, 2013).

Table 1.
Items in the Hare Psychopathy Checklist- Revised (PCL-R)

Could you recognize a psychopath? Click here to watch a short video explaining the core symptoms of psychopathy.

Factor 1 Selfish, Callous and Remorseless Use of Others	Factor 2 Chronically Unstable and Antisocial Lifestyle	Other Items
Glib/superficial charm	Need for stimulation/proneness to boredom	Sexual promiscuity
Grandiose sense of self	Parasitic lifestyle	Many short-term marital relationships
Pathological lying	Poor behavioural controls	Criminal versatility
Conning/manipulation	Early behaviour problems
Lack of remorse/guilt	Lack of realistic, long term goals
Shallow affect	Impulsivity
Callous/lack of empathy	Irresponsibility
Parasitic lifestyle	Juvenile delinquency
Failure to accept responsibility for own actions	Revocation of conditional release

Self Report Inventories

While most clinicians prefer to use the PCL-R to assess psychopathy, researchers have also developed a number of self-report inventories to assess psychopathic traits in non-institutionalized populations (Miller, Jones & Lynam, 2011). Such assessments are cost effective, easy to administer and quick to score.

Some notable self-report psychopathy scales include:

• Self-report Psychopathy Scale (SRP)
• Levenson Self Report Psychopathy Scale (LSRP)
• Psychopathic Personality Inventory (PPI)

Self-report assessments however, are susceptible to denial and manipulation due to the nature of a psychopathic personality. A true psychopath lacks emotional intelligence and self awareness, thus cannot accurately assess their own behaviour and its impact on other people (Cooke et al., 1999). Furthermore, it may be problematic to ask a psychopath to report on the presence or absence of emotions if they have never experienced them (Cleckley, 1976). Due to these limitations, the sole use of self report measures are not recommended for the assessment of psychopathy (Miller et al., 2011). These modes of measurement have nevertheless, led to numerous insights regarding the condition and its relationship with emotion. A combination of methods may therefore be more efficacious to ensure accurate and reliable results.

Emotional Deficits

'"For psychopaths, emotions play only a minor role in motivating and guiding their behavior. In a sense, their conscience is only half formed."

Contrary to popular belief, not all psychopaths are violent, sadistic or even criminal. Unlike sociopaths, these individuals can originate from any sociocultural background, and may comprise a relatively stable portion of the population (Wu & Walsh, 2008). While these individuals may manipulate others for their own personal gain, deviant behaviour comprises only a small facet of a broader syndrome that is marked by distinctive emotional features (Patrick, 1994). Indeed, experimental research has consistently demonstrated that psychopaths display a number of psychosocial, cognitive and neurological abnormalities (Brook, Brieman & Kosson, 2013). Significant defects have also been evidenced in their physiological responses to affective material, and their memory of emotional events (Hastings, Tangney & Stuewig, 2008). Consequently, they face an array of challenges in processing and interpreting emotionally meaningful stimuli.

Emotions are far <more complicated than they originally seem. They are multifaceted and exist as subjective, biological, purposive and expressive components (Blair, 2003). In light of these complexities, there is no single method for their comprehensive measurement. Major advances however have been evidenced within the individual components of emotion such as appraisal, brain mechanisms, physiological response patterns and expressive behaviour such as facial expressions (Scherer, 2005).

Facial Expressions

Facial expressions play a pivotal role in interpersonal relations by conveying emotional information. Others expressions elicit rapid responses that serve important adaptive functions, particularly in the face of potential threat or danger (Decety, Skelly, Yoder & Kiehl, 2014). Due to this, researchers have begun to examine the relationship between psychopathy and the identification of emotional states through facial recognition.

Numerous studies have reported deficits in emotion perception and recognition in psychopathic individuals, especially in terms of negative emotions. Kosson and colleagues (2002) examined facial recognition in male inmates and found that psychopathic men, as defined by the PCL-R, were less accurate at identifying expressions of disgust compared to their non-psychopathic counterparts. Employing a similar paradigm, Blair and colleagues (2004) found that psychopaths displayed a general insensitivity towards expressions of anger and fear. These deficits have also been associated with psychopathic traits in a college sample (Dolan & Fullam, 2006).

A recent meta-analysis aimed to clarify whether these abnormalities extended to positive emotions such as happiness or surprise (Dawel, O’Kearney, McKone, & Palermo, 2012). A systematic search identified 26 studies involving six emotions (anger, disgust, fear, happiness, sadness, surprise) across three modalities (facial, vocal, postural). As hypothesised, psychopathy was negatively correlated with sad facial affect, as well as recognition of less intense displays of affect. Interestingly, significant impairments were also prevalent amongst happy expressions. Holistically, these results suggest that psychopathy may be associated with an overall deficit in affect recognition.

Neurological Functioning

Facial recognition is dependent on a distributed network of brain structures and neurological pathways (Marsh & Blair, 2008). If distinct neurobiological events contribute to the generation of different emotions, which brain structures are most relevant to the emergence of these emotions? And more importantly, do these brain structures differ in psychopathic individuals?

Amygdala

Figure 4. Lateral and dorsal view of the amygdala.

Being a component of the limbic system, the amygdala is involved in a wide range of behavioural and emotional functions (LeDeux, 2007). It plays a central role in aversive conditioning, social interaction, moral judgement and emotional reasoning (Blair, 2003). The emotional deficits consistently demonstrated in psychopathic individuals mimic those found in patients with amygdala lesions. Abnormalities can block episodic memory for emotionally arousing events, disrupting the processing of facial expressions (Blair, 2003). In light of its neurological functions, amygdala dysfunction is one of the core systems implicated in the pathology of psychopathy (Wu & Walsh, 2008).

Neuroimaging studies substantiate that amygdala dysfunction is heavily linked with psychopathy. Tiihonen and colleagues (2000) used volumetric magnetic resonance imaging (MRI) to explore the relationship between amygdaloid volume and psychopathy as measured by the PCL-R.  In line with their hypothesis, reduced amygdaloid volume was associated with high levels of psychopathy. Amygdaloid volume has been correlated with the size and complexity of social and emotional networks in adult humans (Blair, 2003) and a lower density in its volume can significantly hinder ones emotional understanding and interpretation of events. Amygdala responses have also been implicated in psychopaths emotional word processing, particularly those of negative valence (Kiehl et al., 2001).

Prefrontal Cortex

Figure 5. Location of the OFC in an MRI scan.

There is increasing evidence that other neural systems may be dysfunctional in psychopathic populations, more specifically, the prefrontal cortex. The majority of studies exploring this brain region however, have used criminal samples rather than individuals with diagnosed psychopathy (Blair, 2003). There are crucial differences between violent offenders and psychopathic individuals. Whether these findings have direct implications for psychopaths is therefore questionable; these conclusions may demonstrate a core neurological difference between criminal and non-criminal psychopaths.  Further research is required to determine a causal effect.  

One volumetric study has, however, assessed individuals based on the PCL-R. Rain and colleagues (2000) found reduced prefrontal grey matter volume in subjects with high scores, indicative of psychopathic tendencies. Although no generalised frontal cortical dysfunction appear in individuals with psychopathy, there is one region of the frontal cortex that could be impaired; the orbitofrontal cortex (OFC). The medial OFC transmits and receives extensive projections from the amygdala. It is also heavily involved in instrumental learning and response reversal; both of which are significantly impaired in psychopathic individuals (Blair, 2003).   

Why these brain structures differ amongst psychopathy is still unknown. Undeniably, biology plays an important role the development of psychopathy, but is it the underlying cause? The answer to this question is still debatable, thus will vary throughout research. As such, the personality disorder must be viewed as a multidimensional construct involving neurobiological, genetic, and sociobiographical elements (Cooke & Mitchie, 2001). 

Theory

Alongside experimental research, a growing body of empirical evidence has contributed to the development of credible hypotheses that may further explain the mechanisms underlying psychopathy and emotion (Brook et al., 2013). Three of these include: the Violence Inhibition Mechanism, the Somatic Marker Hypothesis and the Under Arousal Hypothesis.

Violence Inhibition Mechanism (VIM)

Figure 6. Can you place yourself in another persons shoes? Empathy serves an important adaptive function in prosocial behaviors.

A relatively new emotion-based theory of psychopathy is the VIM, a theory suggesting that emotional deficits are the result of empathy dysfunction, leading to poor moral socialization (Maddux & Winstead, 2015). The everyday individual can learn about moral transgressions and what will upset others. Seeing someone in distress can serve as a form of punishment, which in turn decreases the likelihood of engaging in callous behaviours. One's ability to empathise creates an emotional experience that dissuades a person from engaging in acts that may inflict pain (Durand & Barlow, 2013).  According to this model, psychopathic individuals fail to experience the fear and sadness of others as aversive (Hastings et al., 2008).  Consequently, they are incapable of acting and behaving in ways which capitulate emotional awareness or understanding.

Some evidence has supported the notion that psychopaths have less mature moral reasoning compared to the general population.  However, subsequent studies have found no significant difference between the reasoning levels of psychopaths and non-psychopathic controls (Durand & Barlow, 2013).  Evidentiary support for the VIM while compelling, is therefore inconclusive.  

Somatic Marker Hypothesis (SMH)

The SMH is a neuropsychological model of behaviour that provides a potential integration of a psychopaths motivational, affective, and information-processing factors (Schmitt, Brinkley & Newman, 1999). When a person experiences any form of arousal, their central nervous system becomes active, and communication between brain circuits generates an emotional feeling, i.e. sadness, excitement etc. These emotional states are automatically linked to memories of what an organism was experiencing at a specific time, thus can be re-created when the organism remembers the experience (Beech, 2015).

According to this model, psychopaths are unable to link memories with emotions. As the psychopathic brain develops, the individual can only approach a person or situation from an emotionless and logical perspective (Hastings et al., 2008).  This theory carries substantial empirical backing, given that the brain areas involved in these functions display consistent abnormalities in psychopathic individuals (Dawel et al., 2012). 

Under Arousal Hypothesis (UAH)

Figure 7. Does skydiving increase your arousal to the optimal level?

Optimal levels of arousal are subjective, thus vary from one person to the next. The UAH suggests that psychopaths have an abnormally low level of autonomic and cortical arousal. These individuals are consequently in a chronic state of stimulation and sensation seeking, explaining their lack of re-activity to emotional stimuli (Durand & Barlow, 2013). Due to this low level of arousal, psychopaths desire a greater variety and intensity of sensory input to increase their arousal to the optimal level (Beech, 2015).

Support for this hypothesis has included considerably low skin conductance to a conditioned stimulus paired with an electric shock, suggesting that psychopaths may not develop anticipatory arousal from the threat of punishment (Maddux & Winstead, 2015). As a consequence, they fail to foresee or consider emotional consequences. Clinical studies have also reported lower heart rate and slower brain activity in psychopathic individuals; all of which are indicative of low arousal (Durand & Barlow, 2013). This could certainly explain the psychopaths tendency to engage in deviant, risky or antisocial behaviours.

Conclusion

Figure 8. Being a multidimensional construct, psychopathy is best conceptualized in its smaller pieces.

In congruence with the discussed research, which theory provides the most plausible explanation? None of these theories can holistically explain a phenomenon as complex as psychopathy. Instead, they each contribute a new piece to the jigsaw puzzle. A combination of environmental, genetic and biological factors have all been attributed to causing or perpetuating emotional deficits in psychopathic individuals (Beech, 2015). There is a general consensus amongst research that a genetic or biological predisposition is necessary for psychopathy, while environmental conditions determine emotional expression (Durand & Barlow, 2013).

How can all of this information be put together to gain a better understanding of psychopathy and emotion? Overall, psychopaths demonstrate a hindered capacity to experience emotion across experimental and observational research. Such deficits interfere with their understanding of emotionally significant events and their subsequent actions (Dawel et al., 2012). While most of these individuals are still rational and cognitively intact, they lack emotional depth. As a result, their appraisals of situations are limited in a way that renders them unable to anticipate emotional consequences (Brook et al., 2013). This has numerous implications for the psychopath in question and clinical research.

Deficits in emotional processing, particularly in the context of fear, pose a hurdle in instrumental conditioning which may prevent healthy or pro-social behaviours (Blair, 2003). To most individuals, the presentation of distress cues such as fearful or sad facial expressions is aversive (Bandura & Rosenthal, 1966). Seeing someone scared or depressed may lead to the interruption of aggression, the initiation of positive behaviours or an active concern for the person in question (Sully, Sonuga-Barke & Fairchild, 2015). However, if distress cues are not processed in a typical manner, these motivations may be non-existent. These impairments may contribute to the psychopaths tendency of engaging in deviant or callous behaviours that may not only harm others, but also harm themselves (Newman & Baskin-Sommers, 2012).

In summary, this chapter provides evidence that psychopaths face numerous challenges in processing and interpreting emotional stimuli. The emotional lives of psychopaths vary dramatically from the rest of the population (Dawel et al., 2012). It is difficult for society to understand their motivations, or ways to effectively manage the disorder. Research examining the emotional deficits in these individuals has given psychologists some insight into their overall demeanor, yet further work is clearly warranted (Kirsch & Becker, 2007). The theoretical models presented in this chapter provide a framework for psychopathy which contribute to the understanding of emotion (Newman & Baskin-Sommers, 2012). As experimental research further clarifies the neural, environmental and behavioural patterns implicated in psychopathy, specific recommendations for its treatment will naturally emerge (Newman & Baskin-Sommers, 2012).

Test Your Knowledge

Point added for a correct answer:    Points for an incorrect answer: Ignore the questions' coefficients: 1 Psychopathy is? A term used to describe the criminally insane A personality disorder characterized by shallow affect, apathy, irresponsibility, impulsivity and poor decision-making A manifestation of extreme antisocial attitudes and behavior A symptom of depression 2 The most valid measurement for psychopathy is? The Levenson Self Report Psychopathy Scale Self report inventories An online quiz The Hare Psychopathy Checklist–Revised 3 Research has consistently demonstrated that psychopaths display? Above average intelligence A number of psychosocial, cognitive and neurological abnormalities in emotional processing A predisposition to commit violent crimes Symptoms of obsessive compulsive disorder 4 Normal amygdala function is one of the core systems implicated in the pathology of psychopathy. True False 5 The underlying cause of emotional deficits in psychopathy is? A traumatic childhood Biological abnormalities A combination of neurobiological, genetic and environmental factors Low cortical arousal

See also

Motivation and emotion/Book/2015/Antisocial Personality Disorder and emotion

Motivation and emotion/Textbook/Emotion/Psychopathy

Motivation and emotion/Book/2010/Sex offender motivation

Motivation and emotion/Book/2010/Antisocial personality disorder

References

Blair, R. J. R. (2003).  Neurobiological basis of psychopathy. British Journal of Psychiatry, 182(1), 5-7. doi: 10.1192/bjp.182.1.5

Blair, R. J. R., & Mitchell, D. G. V. (2009). Psychopathy, attention and emotion. Psychological Medicine, 39(4), 543.

Brook, M., Brieman, C. L., & Kosson, D. S. (2013). Emotion processing in psychopathy checklist-assessed psychopathy: A review of the literature. Clinical Psychology Review, 33(8), 979-995. doi:10.1016/j.cpr.2013.07.008

Cooke, D. J., Michie, C., Hart, S. D., & Hare, R. D. (1999). Evaluating the screening version of the Hare Psychopathy Checklist-Revised (PCL:SV): An item response theory analysis. Psychological Assessment, 11(1), 3-13. doi: 10.1037/1040-3590.11.1.3

Cooke, D. J., & Michie, C. (2001). Refining the construct of psychopathy: Towards a hierarchical model. Psychological Assessment. 13(2): 171–188. doi:10.1037/1040-3590.13.2.171.

Dawel, A., O'Kearney, R., McKone, E., & Palermo, R. (2012). Not just fear and sadness: meta-analytic evidence of pervasive emotion recognition deficits for facial and vocal expressions in psychopathy. Neurosci Biobehav Rev, 36(10), 2288-304. doi: 10.1016/j.neubiorev.2012.08.006.

Decety, J., Skelly, L., Yoder, K. J., & Kiehl, K. A. (2014). Neural processing of dynamic emotional facial expressions in psychopaths. Social Neuroscience, 9, 36–49.

Dolan, M., & Fullam, R. (2006). Face affect recognition deficits in personality-disordered offenders: association with psychopathy. Psychological Medicine, 36(11), 1563–1569.

Durand, V., & Barlow, D. (2013). Essentials of Abnormal Psychology (7th ed.). Boston, MA: Cengage Learning.

Hare, R. D., Harpur, T. J., Hakstian, A. R., Forth, A. E., Hart, S. D., & Newman, J. P. (1990). The revised Psychopathy Checklist: Reliability and factor structure. Psychological Assessment: A Journal Of Consulting And Clinical Psychology, 2(3), 338-341. doi:10.1037/1040-3590.2.3.338

Hart, S. D. & Hare, R. D. (1996). Psychopathy and antisocial personality disorder. Current Opinion in Psychiatry, 9, 129 -132

Hastings, M. E., Tangney, J. P., & Stuewig, J. (2008). Psychopathy and identification of facial expressions of emotion. Personality and Individual Differences, 44(7), 1474-1483. doi:10.1016/j.paid.2008.01.004

Frick, P. J., & Ellis, M. (1999). Callous-unemotional traits and subtypes of conduct disorder. Clin. Child Fam. Psychol. Rev. 2, 149–168.

Jones, A. P., Laurens, K. R., Herba, C. M., Barker, G. J., & Viding, E. (2009). Amygdala hypoactivity to fearful faces in boys with conduct problems and callous-unemotional traits. American Journal of Psychiatry, 166, 95–102.

Kahn, R. E., Byrd, A. L., & Pardini, D. A. (2013). Callous-unemotional traits robustly predict future criminal offending in young men. Law Hum. Behav, 37, 87–97.

Kiehl, K.A., & Hoffman, M.B. (2011). The criminal psychopath: History, neuroscience and economics. The Journal of Law, Science, and Technology, 355-397.

Kiehl, K. A., Smith, A. M., Hare, R. D., Mendrek, A., Forster, B. B., Brink, J., & Liddle, P. F. (2001). Limbic abnormalities in affective processing by criminal psychopaths as revealed by functional magnetic resonance imaging. Biological Psychiatry, 50(9), 677-684. doi:10.1016/S0006-3223(01)01222-7

Kirsch, L., & Becker, J. (2007). Emotional deficits in psychopathy and sexual sadism: Implications for violent and sadistic behaviour. Clinical Psychology Review, 27(8), 904-922. 

Kosson, D., Suchy, Y., Mayer, A., & Libby, J. (2002). Facial affect recognition in criminal psychopaths. Emotion, 2, 398–411. 

Maddux, B., & Winstead, B. (2013). Personality Disorders. In C. Crego, & T. Widger (Eds.). Psychopathology: Foundations for a Contemporary Understanding (pp. 218-233). New York, NY: Routledge Press.               

Marsh, A. A. (2013). What can we learn about emotion by studying psychopathy? Frontiers in Human Neuroscience, 7, 181. doi:10.3389/fnhum.2013.00181 

Marsh, A. A., & Blair, R. J. R. (2008). Deficits in facial affect recognition among antisocial populations: A meta-analysis. Neuroscience and Biobehavioral Reviews, 32(3), 454-465. doi:10.1016/j.neubiorev.2007.08.003

Miller, J.D., Jones, S.E. & Lynam, D.R. (2011). Psychopathic traits from the perspective of self and informant reports: Is there evidence for a lack of insight? Journal of abnormal psychology, 120(3), 758–764. 

Newman, J., & Baskin-Sommers, A. (2012). Cognition–Emotion Interactions in Psychopathy: Implications for Theory and Practice. In H. Hakkanen-Nyholm, & J, Nyholm. (Eds.). Psychopathy and Law: A Practitioner’s Guide. (pp. 80-85). Belmont, CA: John Wiley & Sons, Ltd. 

Patrick, C. J. (1994). Emotion and psychopathy: Startling new insights. Psychophysiology, 31(4), 319-330. doi:10.1111/j.1469-8986.1994.tb02440.

Scherer, K. R. (2005). What are emotions? and how can they be measured? Social Science Information, 44(4), 695-729. doi:10.1177/0539018405058216

Smith, S. T., Edens, J. F., Clark, J., & Rulseh, A. (2014). "So, what is a psychopath?" venireperson perceptions, beliefs, and attitudes about psychopathic personality. Law and Human Behavior, 38(5), 490-500. doi:10.1037/lhb0000091

Sully, K., Sonuga-Barke, E. J. S., & Fairchild, G. (2015). The familial basis of facial emotion recognition deficits in adolescents with conduct disorder and their unaffected relatives. Psychological Medicine, 45(9), 1965.

Viding, E., McCrory, E., & Seara-Cardoso, A. (2014). Psychopathy. Current Biology, 24(18), 871-888.

Woodworth, M., & Porter, S. (2002). In cold blood: characteristics of criminal homicides as a function of psychopathy. J. Abnorm. Psychol. 111, 436–445.

Wu, H., & Walsh, A. (2008). Differentiating antisocial personality disorder, psychopathy, and sociopathy: Evolutionary, genetic, neurological, and sociological considerations. Criminal Justice Studies, 21(2), 135-152. doi:10.1080/14786010802159814,

External Links

• Information sheet on Psychopathy
• Articles about Psychopathy
• TED Talk: How to spot a Psychopath
• Online version of Levenson's Self-Report Psychopathy Scale