Hormone-Behavior Correlates among Male and Female Psychopathic Participants: Relationship to Gray's Model of Behavioral Inhibition and Activation Systems

Open Access
Ghebrial, Marian Erian
Graduate Program:
Doctor of Philosophy
Document Type:
Date of Defense:
August 12, 2005
Committee Members:
  • Peter Andrew Arnett, Committee Chair
  • Michelle Gayle Newman, Committee Member
  • Keith A Crnic, Committee Member
  • Douglas A Granger, Committee Member
  • psychopathy
This study aimed to identify the role of hormonal substrates in relation to Gray’s (1987) model of the behavioral inhibition (BIS) and activation (BAS) systems—constructs proposed to serve a role in the etiology and/or maintenance of psychopathy. Meta-analytic studies have identified a positive relationship between testosterone and aggressive, antisocial, deviant types of behaviors, whereas cortisol has been associated with stress and anxiety. Additionally, a few studies have found reduced cortisol among antisocial, aggressive men. Given that the BIS is associated with inhibited and anxious responding, and the BAS with reward-seeking, impulsive, and sometimes antisocial behaviors, this study proposed that hormones such as cortisol and testosterone, respectively, may significantly correlate with BIS and BAS-driven responses in differentiating psychopaths and nonpsychopaths—a finding that would have important implications for future intervention research and for understanding the nature of this disorder. No study to date has assessed the correlates of both hormones with an experimental measure of BIS and BAS-functioning among male and female psychopathic individuals as this study has done. Utilizing the Iowa gambling task, a behavioral measure commonly used to elicit BIS/BAS activity in response to mixed punishment and reward contingencies, this study’s findings both corroborated and extended previous findings. Both male and female psychopathic analogues as compared to nonpsychopathic analogues responded to the task by utilizing high-risk, disadvantageous decisions. These findings support the notion that psychopathic individuals exhibit low punishment and high reward sensitivity, consistent with Newman’s (1987) response modulation deficit model. Although some of the predicted hormone-behavior relationships were not obtained, exploratory post-hoc analyses revealed unexpected moderating relationships between gender and hormone levels in predicting differential BIS-BAS motivated behaviors. Testosterone (post-task only) moderated the relationship between gender and performance on the gambling task, such that males with the highest testosterone levels during the task made significantly better decisions than males with low testosterone levels. Females with low testosterone levels exhibited significantly better performance than those with high testosterone levels. Additionally, basal cortisol levels also moderated the relationship between gender and task performance. Specifically, females with low basal cortisol levels made significantly more advantageous decisions as compared to males with low basal cortisol levels, such that low cortisol levels optimized female performance, but dampered male performance. The implications of these moderator relationships and the consistencies and inconsistencies obtained in this study as compared to previous literature are enumerated.