Direct and Indirect Relations Between Reactive and Proactive Aggression, Facial Emotion Recognition, and Polymorphisms in the Monoamine Oxidase A and Serotonin Transporter Genes Open Access

LoParo, Devon (2015)

Permanent URL:


Research has demonstrated that individuals high in antisocial traits tend to have difficulty recognizing fearful and sad facial expressions, though researchers have not attempted to link these deficits to specific forms of aggression, such as reactive and proactive aggression. Two genetic markers frequently studied in association with aggression, a repeat sequence in the promoter region of the monoamine oxidase A gene (MAOA-uVNTR) and a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR). These genes are active in brain regions involved in aggression and facial emotion recognition, such as the amygdala and regulatory prefrontal regions, suggesting that facial emotion recognition deficits or biases may serve as endophenotypes for aggression. In a sample of 180 twins genotyped for the MAOA-uVNTR and 5-HTTLPR, we found that the MAOA-uVNTR low-activity allele was associated with a lower proportion of correct fear recognitions, more fear commission errors, and more sad commission errors on a facial emotion recognition task, while the 5-HTTLPR short allele was associated with a higher proportion of correct sad recognitions and more sad commissions. We also found that fewer correct fear recognitions, more fear commissions, and the MAOA-uVNTR risk allele were associated with reactive aggression, while more fear commissions was also associated with proactive aggression. In addition, we found that the proportion of correct fear recognitions, and fear and sad commissions separately mediated the relation between the MAOA-uVNTR and reactive aggression. These results suggest that impaired fear recognition is related to both reactive and proactive aggression. Further, the influence of MAOA-uVNTR on reactive aggression seems to act in part through impaired fear recognition, indicating that facial emotion recognition may be a useful endophenotype for reactive aggression.

Table of Contents

General Introduction 1

Current Study 9

Method 10

Results 17

General Discussion 25

Limitations 29

Implications/Future Directions 31

Conclusion 33

References 34

Figures 41

Tables 44

About this Master's Thesis

Rights statement
  • Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
  • English
Research Field
Committee Chair / Thesis Advisor
Committee Members
Last modified

Primary PDF

Supplemental Files