Genes for Relationships?

I was going through some old files from graduate school the other day, and came across a paper that I wrote as a second-year graduate student in Matt McGue's "Behavioral Genetics" course. The paper, "Behavior Genetic Perspective on Marital Status: Divorce and Marriage" made me realize that I've been somewhat obsessed with the same question for a decade: Where do our thoughts, feelings, and behaviors in relationships come from?

My own history in answering this question is mixed. On the one hand, I was intellectually steeped in the organizational-developmental perspective by Andy Collins, Jeff Simpson, Alan Sroufe, and Byron Egeland. My tl;dr summary of an organizational-developmental perspective (see: The Development of the Person) is the following:

1. The meaning of behavior lies in its organization
2. Organization is revealed through the integration of emotion, cognition, and social interactions.
3. The "seeds" of this organization are planted in the context of our relationships with early caregivers, and development is defined by changes in behavioral organization. 

Fast forward to today, and you could say that there's very little resemblance between what I'm working on now and the organizational-developmental principles I was raised with. And in some ways, you're right. The variance partitioning methods that are common to behavior genetics treat the individual as the unit of analysis. And we make inferences about the degree of genetic and environmental influences for an outcome based on how much monozygotic twins (who share 100% of their genetic variation) and dizygotic twins (who share 50% of their genetic variation) resemble one another for that outcome.

​When these methods are applied to relationship outcomes, we find (not surprisingly, given that the first law of behavior genetics is that everything is heritable) that key relationship outcomes like marriage, divorce, relationship satisfaction, and conflict are all moderately heritable. But what does a heritability estimate tell us about where patterns of thoughts, feelings, and behaviors "come from" or how an individual's behavior is organized in the context of particular relationship with a particular partner who has their own genetic predispositions? This is something that I continue to struggle with.

In an oh-so-prescient paragraph that I wrote in my course paper for Matt McGue's class back in 2007, I stated:

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​A second challenge behavior genetic relationship researchers face is how to best address the inherently dyadic nature of relationships. In studies of relationships, the unit of analysis is the dyad. The question of how to best study the dyadic nature of relationships is particularly difficult to address with behavior genetic designs, given the presumably low rate at which pairs of twins marry other pairs of twins. However, simply assuming that a couple’s risk of divorce is simply the sum of each partner’s liabilities neglects the transactive processes that play out in relationships. It takes two people to form and maintain a relationship, but only one person to dissolve it (Berscheid & Regan, 2005).       

I have obviously not resolved this conflict yet, though I do think that the modern genomic era offers at least some opportunity to better integrate a dyadic perspective into behavior genetic research. A topic for another post!

P.S. Even though I am trying to KonMari my house, I have a special place to keep graded papers from my favorite Carleton and Minnesota professors.