Credit: Pixabay.

Japanese researchers have found a link between a brain area associated with executive control and men’s commitment to their relationship. Executive control is essentially your ability to focus on a task and negate impulsive or irrelevant inputs from your brain. An alternate explanation for executive control is the ability to set aside the prospect of instant gratification in favor of achieving a greater goal — in this case maintaining a desired long-term relationship. The famous Stanford marshmallow experiment is revealing in this respect.

The willpower brain

The experiment conducted by psychologists at Kyoto University involved 50 men aged 20 to 39 years. Each participant had his brain activity monitored with functional magnetic resonance imaging (fMRI) while they completed a go/no-go task — a pass/fail test that is passed only when the Go condition is met and also the No-Go condition fails. Researchers prepared two kinds of stimulus sets for the fMRI study: The first set consisted of 24 cat images for the Go condition and 8 dog images for the No-Go condition. The second set consisted of 8 cat images for the No-Go condition and 24 images of dogs for the go condition.

These emotionally neutral pictures are designed to test self-control, thought to be linked to activity in the right ventrolateral prefrontal cortex (VLPFC). Previously, research had shown that the go/no-go task predicts individual differences in successful self-regulation, regardless of whether the stimuli are sexually stimulating.

The participants were instructed to respond to cat images as quickly and accurately as possible by pressing a button with the right forefinger (Go trial) and to refrain from responding to dog images by not pressing the button (No–Go trial). Each image was presented three times, for half a second at a time, followed by a blank screen for 2 s.

Credit: Kyoto University.

After completing the go/no-go task, the participants, who had all been in a relationship for at least six months, were asked to complete a date-rating task. Each volunteer was shown 48 photographs, consisting of 24 attractive faces and 24 unattractive faces, in a random order, and then asked to rate the degree to which they’d be interested in dating each female.

Enhanced activation of the VLPFC during the go/no-go task was associated with a reduced interest in dating new women. This association was found only among the participants who were in a long-term relationship. Researchers found no such link among men in newer relationships.

“According to our findings, in the beginning of the relationship (which is often more exciting), you might not need ‘willpower’ to resist the temptation of dates with attractive alternatives. However, if you are in a long-term lasting relationship, such ‘willpower’ might be required to remain in the relationship,” Ryuhei Ueda, lead author of the study published in the journal Experimental Brain Research, explained to PsyPost.

“We predict that at the beginning of the relationship, passionate love, instead of willpower would suppress the temptation of extra-pair relationships. But we do not have any data to sufficiently support this idea for now. We need to tackle this issue in the future studies,” he added.

The findings are important from an evolutionary perspective. Males generally have a stronger desire for romantic relationships with more individuals than women. But there’s also such a thing as the “derogation effect”, in which romantically involved individuals tend to exhibit a greater devaluation of alternative partners than single individuals.