3, 2, 1… Go! Name your best friend. Which special person comes to mind? Perhaps you have more than one best friend. These are people that you feel vDiego Guevara Beltránery close with, that you turn to for help, or when you’re simply looking to spend time with someone that you care about. Do you ever wonder, however, how you came to be so close with this one, or few, special people?

Professor Byrd-Craven and her collaborators at Oklahoma State University pay special attention to sex differences in stress to try to explain the psychological and biological mechanisms behind bonding. It appears that, for women (but not men), something that may look negative at first (i.e., higher stress), could have benefits in the long run, such as higher relationship satisfaction.

“Relationships are our most salient stressor [but] also our most powerful buffer,” explains professor Byrd-Craven during her talk at the Evolutionary Psychology Preconference.

Women tend to experience more stress as a result of social exclusion, whereas men tend to experience more stress as a result of threats to status. These sex differences in stress reactivity can then explain, for example, behaviors such as “stress-eating.” With men eating more when stressed about status, and women eating more when stressed about exclusion.

So, we know men and women react differently to different sources of stress, but what does stress have to do with friendships? Unlike men, women who co-ruminate with their friends tend to report more social support and higher relationship quality than women who do not co-ruminate. Men just don’t seem to co-ruminate with their male friends at all.

Given that co-ruminating can have negative implications such as inducing symptoms like anxiety, or information shared could be used in potentially harmful ways (e.g., gossip), it is a bit of a wonder that women co-ruminate with their close friends.

These findings led Byrd-Craven and colleagues to test whether co-rumination could be a function of bonding in female friendships. They brought participants to the lab and had dyads of female friends discuss a problem for thirty minutes. They also measured participants cortisol before and after they discussed the problem, as well as how much attention participants paid to negative affect during conversation.

They found that friends who co-ruminate show higher stress synchronicity, which in turn was explained by how much attention participants payed to their friend’s negative affect.

Byrd-Craven and colleagues believe their results suggest that women who are willing to incur the “cost” of co-rumination with a friend are essentially saying: “hey, I will feel stress with your stress because you are my friend and I care about you.” 

Written By: Diego Guevara Beltrán, BSc/BA, PhD student in Social Psychology, Cooperation and Conflict Lab, Arizona State University

Session: Examining the importance of biosocial trade-offs in understanding female sociality, part of the Evolutionary Psychology Preconference, held on the 7th of February 2019.

Speaker: Jennifer Byrd-Craven, Oklahoma State University.