Increased parasympathetic activity and ability to generate positive emotion: The influence of the BDNF Val66Met polymorphism on emotion flexibility

Autonomic Nervous System Activity During Positive Emotions: A Meta-Analytic Review

Autonomic nervous system (ANS) activity is a fundamental component of emotional responding. It is not clear, however, whether positive emotional states are associated with differential ANS reactivity. To address this issue, we conducted a meta-analytic review of 120 articles (686 effect sizes, total N = 6,546), measuring ANS activity during 11 elicited positive emotions, namely amusement, attachment love, awe, contentment, craving, excitement, gratitude, joy, nurturant love, pride, and sexual desire. We identified a widely dispersed collection of studies. Univariate results indicated that positive emotions produce no or weak and highly variable increases in ANS reactivity. However, the limitations of work to date – which we discuss – mean that our conclusions should be treated as empirically grounded hypotheses that future research should validate.

The BDNF Val66Met polymorphism impacts victim's moral emotions following interpersonal transgression

Immoral behaviors make individuals abominate and punish transgressors. Inspired by the associations between the Val66Met polymorphism of brain-derived neurotropic factor (BDNF) gene and emotional responses following negative events, we investigated whether this polymorphism was also associated moral emotions such as punishment and forgiveness following interpersonal transgression. To do so, we categorized 340 individuals according to the BDNF Val66Met and assessed moral emotions by using 12 hypothetic scenarios in different conditions of intention and interpersonal consequence. The results indicated that this polymorphism was significantly associated with moral aversion and punishment towards transgressors. Victims with the Val/Val genotype expressed less aversion and punishment than the Met carriers, regardless of intention and interpersonal consequence. Moreover, this polymorphism was associated with forgiveness. Victims with the Val/Val genotype expressed more forgiveness than the Met carriers. Taken together, these findings highlight the importance of the BDNF Val66Met to moral emotions.