خمیازه مسری و اختلالات فکری و روانی

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.

Yawning is a stereotyped behavior that, in our evolutionary history, has clear, deep roots as evidenced by its proliferation in mammals as well as many other vertebrates (Argiolas and Melis, 1998 and Lehmann, 1979). It is clearly characterized by long inspiration followed by a shorter expiration (Argiolas and Melis, 1998). While literature concerning the pharmacology and functional anatomy of yawning is not lacking (Argiolas and Melis, 1998, Guggisberg et al., 2010 and Nahab et al., 2009), the primary facet of yawning of interest is the phenomena of contagious yawns, specifically within the context of psychopathology. Contagious yawns, which are spurred by yawn, thinking, hearing, reading, or observing another conspecific (or other species), have been linked to empathy (Lehmann, 1979, Platek et al., 2003 and Platek et al., 2005). They are even documented in other familiar animals such as Pan Troglodytes and Canis Familiaris and have been linked to empathy ( Campbell and de Waal, 2011 and Romero et al., 2013). The anatomy and pharmacology of yawning and its contagious nature are beginning to be investigated, with oxytocin playing a large role as well as the posterior cingulate cortex (PCC), precuneus, bilateral thalamus, and parahippocampal gyrus (PHG) ( Platek et al., 2005 and Sanna et al., 2012). Interestingly, Schürmann et al. (2005) found that the mirror-neuron system is not directly activated in contagious yawning, suggesting that the action is automatic and not imitated. Norscia and Palagi (2011) found that people show a large susceptibility to contagious yawns when elicited by a related individual in terms of occurrence and frequency of yawns. For strangers, they found that people show a marked latency period of contagious yawns, strongly suggesting a component of familiarity involved with the contagion. Variations in susceptibility to contagious yawning are already known to occur in certain populations. Age is known to affect the likelihood of contagious yawning; as age increases, contagious yawning decreases (Bartholomew and Cirulli, 2014). Further, children on the autism spectrum are less likely to demonstrate contagious yawning (Giganti and Esposito Ziello, 2009 and Senju et al., 2007), which is speculated to have a strong relationship to the empathetic deficits seen in this population. 1.1. Psychopathy Empirical support for yawning having its evolutionary roots in empathic behavior is growing (Campbell and de Waal, 2011). Psychopathic traits, then, become a curious angle in which to view contagious yawning in our species. Psychopathy is characterized by a general antisocial lifestyle including being selfish, manipulative, impulsive, fearless, callous, domineering, and particularly lacking in empathy (Hare, 2003 and Weber et al., 2008). The disorder is typically assessed via the Psychopathic Check List-Revised (PCL-R) developed by Hare (2003) or the Psychopathic Personality Inventory (PPI-R) developed by Lilienfeld and Widows (2005). Psychopathy and its close relative Antisocial Personality Disorder are found overwhelmingly in males (Cale and Lilienfeld, 2002). Additionally, psychopathy carries specific brain abnormalities including structural and functional impairments of the orbitofrontal–ventromedial prefrontal cortex as well as the amygdala (Gao et al., 2009 and Weber et al., 2008). The PPI-R operationalizes two discrete components within psychopathy: a primary (affective) and secondary (behavioral) facet (Hare, 2003 and Lilienfeld and Widows, 2005), where the primary facet encompasses features including cruelty, lack of affect and empathy, while the secondary facet encompasses features such as impulsivity and aggression. Psychopaths demonstrate an overall small but marked decrease in the ability to recognize emotion in others (Kosson et al., 2002 and Wilson et al., 2011), which is also associated with decreased amygdalar function, particularly with fearful faces (Jones, Laurens, Herba, Barker, and Viding, 2009). Kosson et al. (2002) showed a slight overall decreased ability to recognize emotion, but a large deficit in recognizing disgust in others when the task involved non-verbal responses. It has also been shown that psychopaths fail to exhibit a conditioned response to aversive Pavlovian conditioning (Flor, Birbaumer, Hermann, Silvio, and Patrick, 2002), which suggests deficiencies in amygdala-dependent memory. What sets psychopathy apart from its close relatives Conduct Disorder and Antisocial Personality Disorder is its distinct emotional component. That is, psychopathy involves a prevalent emotional profile consisting of a considerable reduction in or lack of empathy (Frick et al., 1994 and Hare, 2003). Psychopathy has also been found to be inversely related to the ability to perceive emotion (in both male and females) and managing emotion (only in men) (Lishner, Swim, Hong, and Vitacco, 2011). 1.2. Hypothesis Given the nature of psychopathy and yawning discussed herein, the current study aims to examine the relationship between contagious yawning and psychopathic traits. This will be examined both by a yawning paradigm designed by the current researchers (modeled after Platek et al., 2005) as well as an emotion-related startle paradigm (ERS) previously used in Anderson, Stanford, Wan, and Young (2011). Affective potentiation of the acoustic startle reflex (by Electromyograph [EMG] and Galvanic skin response [GSR]) is one of the most prominent psychophysiological measures of amygdalar responsiveness (Davis, 1989, Lang et al., 1990 and LeDoux et al., 1988). Psychopaths reliably demonstrate an impairment of potentiation of the startle reflex (Patrick, Bradley, and Lang, 1993), while healthy controls reliably potentiate with negative affective valence and attenuate the fear response with positive affective valences (Lang et al., 1990). What's more, Patrick et al. (1993); Patrick (1994) connected the lack of potentiated startle in psychopathy to the emotional facet of the PCL-R (Hare, 2003) while the behavioral facet was found to be unrelated. Further, given the growing evidence that contagious yawning and empathy are evolutionarily related, a connection between psychopathy and yawning maintains sufficient precedence. To our knowledge, such an examination has not been done in high psychopathic trait individuals, nor have contagious yawning been addressed using ERS. In our case, we expect to find a connection between psychopathic traits and a decreased susceptibility to contagiously yawn.

To our knowledge, no experiments showing the relationship between startle potentiation, psychopathy, and yawning have been published. It is, however, established the relationship between psychopathy and startle as well as the relationship between yawning and empathy (Norscia and Palagi, 2011). Though pilot in nature, our data suggests that startle potentiation to negative stimuli may predict one's susceptibility to contagious yawning. In line with the theories presented on yawning and startle, it is reasonable to expect that low startle potentiation is related to yawning susceptibility, as affect is highly considered in both realms of research. There is also an evolutionary justification for the results found herein. While psychopathic traits are not the direct inverse of empathetic traits, both are constructs that seem to capture polarized behaviors. Coldheartedness refers to a dearth of social emotion (Lilienfeld and Widows, 2005). That is, it is an inconsideration of the emotional state of others. Our results, then, fit well into the evolutionary model that contagious yawning in our species is a function of empathy, as we have shown that those who are characteristically lacking in empathy are less susceptible to a contagious yawn when prompted in a paradigm known to induce contagious yawning in normal individuals (Platek et al., 2003). The results of these two experiments are clear indicators that psychopathy is a robust, multifaceted disposition, where a strict interpretation of an overall PPI-R score is not necessarily a predictive one. Rather, attention to subscales and, of course, clinical evaluations are clearly more appropriate for predictability. While gender effects between yawning susceptibility may exist, the gender effect is controlled in the current study. Of course, the use of females in the startle-yawn paradigm would be important in future studies, as psychopathy is not a sex-dependent phenomenon (Anderson et al., 2011). The emotional component of the PPI-R is likely the most relevant to the experiments herein. While the overall measure is possibly too broad a measure for these purposes, it nonetheless lends support to the developing idea that psychopathy, empathy, and contagious yawning are related.