How Your Relationships Shape You — For Better Or Worse

Illustrated by Elliot Salazar.
By Brent Mattingly
You have likely heard someone in a relationship say something like, "She makes me a better person." Alternatively, you may have also heard people say things like (with apologies to Stone Temple Pilots) "I'm half the man (or woman) I used to be." Though these statements convey feelings of overall relationship satisfaction in the former case, or dissatisfaction in the latter case, something else important is being communicated — that romantic partners are capable of modifying our sense of who we are as individuals (i.e., sense of self).
Recently, my colleagues (Dr. Gary Lewandowski and Dr. Kevin McIntyre) and I theorized that relationships can affect individuals' sense of self along two primary dimensions — direction and valence. Direction means that stuff can be added or subtracted from our sense of self — that is, we can gain identities and perspectives we never had (e.g., we might add the identity of "Trekkie" if our partner introduced us to Star Trek), or we can lose existing aspects of who we are (e.g., we might stop identifying as a "wine aficionado" if our partner discourages alcohol consumption). Valence refers to how positive or negative we view our modified sense of self. These two dimensions can therefore create four types of self-concept change that occur to varying degrees within a relationship, each of which has important consequences for the relationship:
1. When individuals gain positive aspects, we term this self-expansion. Often, self-expansion occurs when couples have new and interesting experiences together, though it can also occur simply by picking up a partner's positive habits (e.g., exercising more).
2. However, not all additions to the self are positive; in fact, it is possible to gain negative attributes from a partner, a process we call self-adulteration (though we just as easily could have called this the "Sandy from Grease" effect). Self-adulteration could occur by picking up bad habits from a partner (e.g., smoking) or feeling more negative emotions because of the relationship (e.g., anger, frustration).
3. Just as the self-concept can grow, it can also shrink. When individuals lose positive aspects of their self-concept, they experience self-contraction. For example, individuals may have sacrificed important hobbies, or neglected valued friendships.
4. Finally, romantic partners can help facilitate self-pruning, which occurs when negative aspects of the self are decreased. A partner who helps you kick a bad habit (e.g., smoking) would lead to self-pruning.
So, why are these distinctions important? First and foremost, different combinations of self-change are differentially associated with relationship quality. Relationships high in self-expansion and self-pruning are associated with greater satisfaction and commitment, more passionate and companionate love, and are less prone to infidelity. Conversely, relationships high in self-adulteration and self-contraction tend to be of poorer quality, relatively low in love, and are more prone to cheating.
What this means, then, is that when relationships cause individuals to develop a more positive self-concept — either through gaining positive stuff (self-expansion) or losing negative stuff (self-pruning) — there are a range of positive outcomes that are beneficial for the relationship. On the other hand, when relationships cause individuals to develop a more negative self-concept — either through losing positive stuff (self-contraction) or gaining negative stuff (self-adulteration) — individuals aren't as attached to their relationships and are more likely to have a wandering eye. It is still much too early to establish a causal direction — it's equally plausible that when individuals are satisfied and committed, they perceive their relationships to be more self-expanding and self-pruning and less self-contracting and self-adulterating.
However, the link between who we are (i.e., our self-concept) and how our relationships function is clear, and this is an important point. Individuals might not often consider how their relationships affect their sense of self, even though these self-concept changes have important implications for their relationships.

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