Neuroscientists find this is the key to a long-lasting relationship

Especially poignant in this age of lockdowns and social distancing, a new study conducted at the University of Colorado, Boulder has found the first-ever neural evidence that absence really does make the heart grow fonder.

These findings strongly suggest that our brains just don’t provide us with the same level of pleasure or fulfillment when interacting with a loved one if we never get some time away from each other.

Romantic partnerships, or any personal relationship for that matter, are often defined by the amount of time we spend with a particular person. Spend all day every day with a loved one and you’ll probably end up getting a bit annoyed with each other at some point, but once that person has packed up and left for the weekend, most of us will start to miss the very traits that annoyed us just a few days ago.

The same goes for friendships; spend every weekend with the same friend and by week five you’re probably going to want to take a break from that person. But, stay away from that friend for a few months and you’ll be excited to see them again at some point.

Due to COVID-19, millions of families and couples are currently confined indoors all day, but conversely, many others have been separated from their friends and families for extended periods during this pandemic. These two situations represent two sides of the same human behavioral coin.

Now, this hot-off-the-presses research is providing the first brain-imaging backed evidence that “absence makes the heart grow fonder” isn’t just an old saying.

“In order to maintain relationships over time, there has to be some motivation to be with that person when you are away from them,” says lead author Zoe Donaldson, an assistant professor of behavioral neuroscience at the University of Colorado Boulder, in a university release. “Ours is the first paper to pinpoint the potential neural basis for that motivation to reunite.”

Donaldson and her team have been studying prairie voles, a type of rodent found in central North America, for several years to try and gain a better understanding of why certain living beings seek out life-long close relationships and bonds. Why these rodents? Prairie voles are one of the only mammalian species besides humans that mate for life.

“We are uniquely hardwired to seek out close relationships as a source of comfort, and that often comes through physical acts of touch,” she adds.

Tiny cameras and a new form of brain imaging were used to observe neural activity in dozens of test voles at three distinct points in time. First, when one vole initially met a potential life partner, three days after a vole couple had first mated, and then again 20 days after a vole couple had “moved in together.” Vole brain activity was also observed as the rodents interacted with other voles that weren’t their partner.

Prior neural research on humans had found that the region of people’s brains that activates during drug use (heroin, cocaine) displays similar behavior when individuals hold hands with their romantic interest. So, researchers expected to find similar activity in the rodents’ brains. Surprisingly, however, voles’ brains didn’t react differently to their mate until they had been separated from one another.

The voles’ brain cells only activated in that particular region (nucleus accumben) once they laid eyes on their partner after some time apart, and started running towards one another. The longer a vole couple had lived with each other, the more pronounced their neural activity upon reuniting. On the other hand, when a vole approached a “stranger,” a completely different set of neural cells fired up.

“This suggests that maybe the recruitment of these cells for this new purpose is important for forming and maintaining a bond,” Donaldson theorizes.

Of course, more research is necessary before any definitive conclusions can be drawn regarding humans, but these findings are still quite significant. This is the first-ever clear cut evidence that monogamous mammals are neurally “hardwired” to miss loved ones while away from each other.

The study also partially helps explain why lockdown measures and social distancing are taking such a heavy mental toll on all of us. The longer we’re separated from the people we care about, the more our brains desire to reunite.

“These negative feelings so many of us are experiencing right now may result from a mismatch: we have a neuronal signal telling us that being with loved ones will make us feel better, while practical restrictions mean this need is going unmet,” Donaldson concludes. “It’s the emotional equivalent of not eating when we are hungry, except now instead of skipping a meal, we are slowly starving.”

The full study can be found here, published in Proceedings of the National Academy of Sciences.