Relationships are More Than Skin Deep: Associations Between Testosterone, Relationship Quality, and Prosocial Behavior

Abstract

Testosterone is a steroid hormone that is important for close relationship processes (Edelstein & Chin, 2018). For instance, people who are single tend to have higher levels of testosterone compared to people who are in committed relationships (Mazur & Michalek, 1998), suggesting that testosterone lowers once one is in a relationship. Furthermore, lower testosterone might be functional for maintaining relationships: Both men and women who have lower testosterone report higher relationship quality (e.g., Edelstein, van Anders, Chopik, Goldey, & Wardecker, 2014). However, only a few studies have examined associations between testosterone and relationship quality in individuals, let alone in a sample of couples, and studies that include couples tend to have relatively small, homogeneous samples. Thus it is not yet clear whether similar testosterone-relationship quality links and any dyadic associations between partners would be found in other samples. The first goal of this study was to examine whether people reported higher relationship quality when they or their partners have lower testosterone. I also examined how people with lower testosterone behaved towards their partners. Given that lower testosterone is thought to be associated with nurturance and caregiving (van Anders, Goldey, & Kuo, 2011), the second goal of this study was to examine whether people with lower testosterone would be more likely to behave in more nurturant (i.e., prosocial) ways towards their partner. Finally, the third goal was to test prosocial behavior as a potential mechanism underlying testosterone-relationship quality links. To address these questions, I analyzed data from 595 heterosexual couples drawn from three samples (college-aged couples, couples with children, and newlywed couples) that included baseline measures of salivary testosterone, self-reports of relationship quality, and partner interactions that were coded for prosocial behavior. I found that, in the college-aged couples and couples with children, women who had lower testosterone indeed reported higher relationship quality and showed more prosocial behavior. In contrast to expectations, men in the newlywed sample who had lower testosterone reported lower relationship quality and engaged in less prosocial behavior. I also found dyadic associations: In the college-aged couples and couples with children, women who had lower testosterone had partners who reported higher relationship quality; in the newlywed sample, women who had lower testosterone had partners who reported lower relationship quality. I did not find that prosocial behavior accounted for any testosterone-relationship quality links, suggesting that people with lower testosterone felt better about their relationships, but not necessarily because they or their partners were more behaving in more prosocial ways. I discuss potential explanations for discrepant findings across samples: The newlywed couples knew prior to their lab session that they would be discussing a disagreement, which could have caused anticipatory increases in testosterone. This study advances social neuroendocrinology work by assessing the extent to which previous testosterone-relationship quality findings replicate in larger samples of couples and contributes important new information about the associations between testosterone and prosocial behavior.