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Why People With Borderline Personality Pick Poor Partners

A new study shows why people with borderline put on relationship blinders.

The relationships of people with borderline personality disorder (BPD) are known to be fraught with difficulty, due at least in part to the tendency these individuals have to pick the wrong partners. Perhaps you have a friend who has BPD and you’ve gotten used to helping her through more than her share of bitter endings. You wish that you could help her avoid getting into these difficulties in the first place so that she could see the warning signs in a potential partner before the relationship heads toward its inevitable downhill path.

According to a recent study by University of Heidelberg’s Haang Jeung and colleagues (2020), the problem lies in part within the tendency for people with BPD to have less “inequity aversion” in the social decision-making process than do their healthier counterparts. In other words, most people don’t want to get involved with someone who they think will take advantage of them due to a basic sense of fairness. The question the research team tested was whether those with BPD have blinders on when contemplating a new and potentially toxic relationship.

There may be times when you’ll do something for someone else without thinking of your own rewards, but over the long run, you would expect to get as much as you give from your close relationships. You will leave a relationship that involves excessive violation of the normal “tit for tat” that characterizes social decision-making.

Jeung et al. propose further that, in general, people with BPD are highly sensitive to the possibility of being excluded in social situations. They may be willing to accept inequity if they feel this will help keep them included within the group. Perhaps you’ve noticed your friend with BPD being willing to pay more than her share of the tab. She's willing to forgo equitable treatment so that she'll keep being invited to the group's get-togethers.

What intrigued the German researchers was the question of what people with BPD would do when they're the ones deciding who's in and who's out. Would they make fair or unfair decisions about the others in their group? This question became the basis for the experimental part of the Jeung et al. study involving a 3-person decision-making game with various possible payoffs.

The basic framework of the experiment was as follows. One person was designated as the “proposer” and could choose to form a two-person coalition (dyad) or three-person coalition (triad). By choosing only one other person for the coalition, by necessity the third person would be excluded. Choosing to exclude the third person would be a poor choice, however, because then everyone would earn fewer points, and hence receive less payment. The bargaining part of the game involved the proposer offering to divide the payment with the others in the group who, in turn, could try to negotiate a better deal.

Returning to the study’s hypotheses, the main point of the game was to determine whether participants with BPD would be more likely to prefer dyads vs. triad (meaning that they would impose exclusion on that third person), and whether they would be more generous in their offers to their interaction partners than would the comparison healthy controls.

In the second phase of the study, all participants rated the fairness of choices in a simulated game sequence they watched in which the proposer adopted the dyad strategy only (exclusion), the triad strategy only (inclusion) or a mixed strategy. Then, the participants selected the proposer type they would prefer to play with in a game. People with BPD, according to the study’s predictions, should be more likely to prefer the inclusion strategy as well as to regard inclusion to be a fairer game-playing approach.

A sample of 26 women with BPD (ranging from 18 to 40 years of age) were contrasted with 29 healthy controls (HC) in the role of proposer. The responders were 120 university students chosen from an online recruitment system. One participant (BPD or HC) was paired with two of the responders in each round of game-playing.

Now that you’ve read the complexities of this experimental set-up, ask yourself how you would behave in a similar situation. Would you be likely to try to maximize rewards for the group or would you be out for yourself? Who would you rather be partnered with if this person was making decisions for you?

The findings showed that the women with BPD were indeed as likely to choose inclusion as often as did the healthy controls in the dyad-triad part of the study. In other words, they were likely to make fair decisions and to perceive inclusion as a fairer strategy to the same extent as did their non-BPD counterparts. However, when it came to picking an interaction partner in the study's second phase, the results were not quite so rosy. The women with BPD were more likely to choose a proposer who either followed the dyadic or mixed strategy than did the HC’s, rather than make the "better" choice of picking someone whose behavior would benefit the entire group.

Putting these findings into plain terms, the authors suggested that “patients with BPD tend to rush headlong into disaster with their eyes wide open.” The BPD women knew that they would stand to lose more with the inequitable proposer, but chose to be in the group with that person anyhow.

In more formal terms, Jeung et al. related this finding to the schema held by people with BPD of the “punitive parent mode” with its accompanying “self-hatred, shame, self-devaluation, and self-punishment” to “explain the patients’ behavior of submissive acceptance of maltreatment in our experiment.” They expect poor treatment, and this is what leads them to turn a blind eye to an unfair partner.

Perhaps on the more positive side, people with BPD appeared to be more likely, when in control of the choices, to make their own decisions on the basis of fairness, suggesting their greater sensitivity to unfairness.” This “injustice sensitivity,” as the authors put it, comes from a “fierce determination for justice to prevail in all circumstances. Having themselves been treated unjustly by their parents, their hearts (and economic decisions) go out to others who they perceive as potential victims as well.

To sum up, people with BPD may themselves be acutely aware of the need to treat others fairly, and to side with the victim whom they perceive to be the target of mistreatment. However, in choosing a partner they may be unable to avoid the disaster that comes from picking someone who will treat them unfairly. Helping these individuals realize that they deserve better treatment seems to be what's needed to put them on a path to making better relationship choices.

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Jeung, H., Vollmann, M., Herpertz, S. C., & Schwieren, C. (2020). Consider others better than yourself: Social decision-making and partner preference in borderline personality disorder. Journal of Behavior Therapy and Experimental Psychiatry, 67. doi: 10.1016/j.jbtep.2018.11.004

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