Hand holding for pain reduction must not be underestimated, suggests new research.
Prosocial behavior is deeply ingrained in us as humans, and the way our bodies respond to others is a testament to this.
When you add romance to the mix, things get even more interesting. Scientists have shown that the hearts of romantic partners beat at the same rate, making the phrase "our hearts beat as one" more true than previously thought.
Last year, a study led by Pavel Goldstein — a postdoctoral researcher in the Cognitive and Affective Neuroscience Lab at the University of Colorado, Boulder — focused on how this physiological synchronicity is affected when one partner is in pain and the other tries to comfort them.
The study showed that holding your partner's hand can ease their pain, raise your empathy, and even cause you and your partner's heart and respiration rates to synchronize.
This phenomenon is called "interpersonal synchronization," and now, the same Pavel Goldstein has explored it further. Along with his team, Goldstein chose to focus on brain wave patterns and how they behave when partners try to alleviate each other's pain.
To the authors' knowledge, this is the first time that "brain-to-brain coupling" has been studied in the context of pain reduction through the human touch.
The findings were published in the journal Proceedings of the National Academy of Sciences.
Hand holding, brain coupling may kill pain
Goldstein and colleagues asked 22 heterosexual couples to sit through different scenarios while their brain activity was monitored using an electroencephalograph.
The participants were aged between 23 and 32 and had been together for at least a year. During the study, they were asked to either sit together in the same room without touching, sit together and hold hands, or sit in separate rooms.
The scenarios — which lasted for about 2 minutes each — were then repeated, with the women subjected to mild heat-induced pain on their arms.
The study revealed that for the partners, simply being in each other's presence correlated with synchronicity in a brain wavelength called the alpha mu band, which is involved in focus and attention.
Brain coupling increased even more if the partner held the woman's hand while she was in pain. Conversely, if the partners didn't hold hands while the woman was in pain, their brain waves stopped coupling.
"It appears that pain totally interrupts this interpersonal synchronization between couples and touch brings it back," says Goldstein.
Additionally, the researchers tested the male partner's levels of empathy, which revealed that high empathy correlated with more intense brain coupling. This, in turn, lowered the women's pain. The authors explain:
"Our findings indicate that hand holding during pain administration increases brain-to-brain coupling in a network that mainly involves the central regions of the pain target and the right hemisphere of the pain observer."
They add, "Interpersonal touch may blur the borders between self and other." And while the study did not look at same-sex couples or other relationships apart from heterosexual, romantic ones, Goldstein emphasizes how powerful the human touch can be in easing pain.
"We have developed a lot of ways to communicate in the modern world and we have fewer physical interactions," he says. "This paper illustrates the power and importance of human touch."
Goldstein also adds that further studies are needed to understand the precise mechanisms that may explain exactly how hand holding can kill pain in the brain.