It doesn’t take much to figure out that romantic relationships are hard work. However, recent U of T research shows that maintaining relationships may come more naturally to some. According to Raluca Petrican, PhD candidate at U of T’s Neuropsychology and Cognitive Science Lab, a specific brain network involved in processing the potential alternatives to current relationships might be critical in shaping relationship stability.
Previous research has shown that relationship stability is highly influenced by romantic commitment. These studies describe commitment as the orientation toward the long-term future of the relationship, as well as motivation to keep up the relationship regardless of immediate difficulties or temptations. Commitment has also been linked with the personality trait of conscientiousness, a factor characterized by controlling impulses and long-term goal setting.
In one set of studies, Petrican and her colleagues set out to find what are the brain areas associated with the motivation to persist in relationships. In other words, what parts of the brain are active in romantic commitment? This was an attempt to provide a neurological model that could account for the connections between conscientiousness, commitment, and relationship stability.
Based on the strong similarities between commitment and studies of self-control and emotional regulation, the researchers identified a network of areas in the dorsolateral prefrontal cortex (PFC) as the likely candidate for the regulation of commitment in relationships.
“There is literature on self-control and self-regulation, but it’s actually more in neuroeconomics,” says Petrican. “Basically they’re looking at what brain areas light up when participants choose to delay gratification, as in choosing a larger monetary reward that is offered later in the future, as opposed to an immediate but smaller reward. A couple of areas in the dorsolateral prefrontal cortex seem to be pivotal for performance on delayed gratification tasks.”
“There is also another branch of literature in emotion-regulation showing that those same areas seem to be important in minimizing negative or positive emotions, depending on what the goal is. It has to do with modulating one’s raw emotion in a response to a situation. That makes perfect sense, because in relationships you have to somehow down-regulate the attractiveness of potential partners, but you also have to down-regulate potential negative responses that are elicited by the partner.”
Since these dorsolateral PFC functions are so closely related with the processing of relationship commitment, Petrican and her colleagues hypothesized that individual differences in the efficiency of this brain network might be able to predict differences in commitment, as well as conscientiousness.
In order to assess differences in the efficiency of dorsolateral PFC processing, researchers gave participants a working memory task. In general, working memory involves the ability to acquire and manipulate newly acquired information. The capacity of our working memory is highly correlated with IQ and “is related to what is usually perceived as intelligent behaviour, in terms of being able to deal with novel situations, drawing upon previous experiences, but in a flexible manner,” says Petrican.
Since individuals vary in their working memory capacity, this can explain why some people show higher commitment than others. According to Petrican, “Once we control for how happy they are in the relationship, still, there are some people who just cannot commit, who cannot disregard potential attractive alternatives to the relationship.”
On top of the working memory task, the participant group, which consisted of dating couples who had been together for at least eight months, also completed personality tests and questionnaires assessing their commitment level.
The results indicated that larger working memory capacity and therefore more efficient dorsolateral PFC functioning, was correlated with higher romantic commitment, as well as greater conscientiousness. Petrican and her colleagues concluded that individual differences in dorsolateral PFC functioning influence both conscientiousness and commitment. What’s more, “as far as raw personality factors are concerned,” says Petrican, “we were thinking that conscientiousness would be a personality factor that would mediate the effect of efficiency of dorsolateral prefrontal functioning on commitment.”
Consistent with their results, a later study by another team of researchers used neuroimaging to show that the dorsolateral PFC is particularly active when people in dating relationships look at pictures of potential alternatives to their relationship. This lends support to the idea that dorsolateral PFC functioning mediates relationship commitment and the resulting relationship stability.
One of the intriguing intersections in research involving the dorsolateral PFC is the study of neuroeconomics. Neuroeconomics looks at the neural processes underlying our everyday economic decision-making, and is typically studied by giving participants gambling tasks while monitoring their brain activity. The elements of self-regulation involved in making decisions about money are in fact also seen in romantic commitment, with processes like delaying gratification in return for larger long-term relationship satisfaction.
But what are the implications of this common brain process? Does it mean that we approach our relationships in the same that we approach monetary rewards? Are we constantly evaluating the cost and benefits in our environments, including even our interpersonal relationships?
According to Petrican, the costs and benefits of a relationship might only be relevant in the short term, while other processes, like defining one’s sense of self in terms of one’s partner, might be involved in more long term relationships.
“I think that the cost-benefit analysis applies more to the beginning phases of a relationship,” says Petrican. “So we’re talking about a dating relationship, around one to two years. I think that once you’re talking about a 30- 40-year marriage or common-law relationship, there is literature showing that a sense of investment that partners have in their relationship will actually guide their decision of staying or not, more so than their actual satisfaction. In the long-term, the other becomes somehow incorporated into your sense of who you are. That’s the basis of really long-term relationships.”
Another related branch of research looks at relationship stability in nonhuman animals. However, instead of applying a cognitive self-regulation framework, animal research looks at relationship stability from a hormonal standpoint. For example, the hormone oxytocin seems to regulate several social processes in animals, including bonding and physical contact. Male mice that are unable to produce oxytocin can no longer recognize the scent of females they have already encountered. They can retrieve this function if oxytocin is infused into their brains.
What’s more, one rodent called the prairie vole forms stable monogamous pairs, thanks to a high concentration of the neurotransmitter vasopressin in a brain region called the ventral pallidum. Meadow voles, a closely related rodent, do not form monogamous pairs, and have fewer vasopressin receptors in these same brain areas. However, if male rodents are genetically engineered to produce more vasopressin receptors in the ventral pallidum, they will form a stronger relationship with their female mate, as if they were forming monogamous pairs.
But when we look at relationship stability in humans, it seems that social processes are regulated predominantly through cognitive mechanisms. Petrican explains, “This has to do with what is perceived to be uniquely human in terms of reappraising the situation. So if you were to ask individuals on a raw emotional level, ‘Are you tempted to go astray?’—it’s not that they would say no, but it’s just that they will be able to modulate, to somehow down-regulate that temptation.
“What working memory and dorsolateral prefrontal function regulates is more the framing of the temptation, but not the actual emotional response.”
