When Pavel Goldstein’s oldest daughter was being born, his wife asked him to hold her hand during the delivery. If you’re a parent, know any parents, or have seen the "childbirth" episode of any TV show, you know what happened next. He offered her his hand and she squeezed it while feeling an extraordinary amount of pain.
That simple gesture “was somehow helpful for her,” Goldstein remembers. “It helped reduced her pain. After, I was thinking about that. What does it mean? How was it helpful? It was at this point I started to think about researching social touch and pain.”
That was five years ago. Goldstein, a postdoctoral research associate in the department of psychology and neuroscience at the University of Colorado Boulder, has since been investigating how something as basic as touch could lower the amount of pain another person feels, along with his collaborators Irit Weissman-Fogel and Simone Shamay-Tsoory at the University of Haifa in Israel.
The idea that social touch can act as an analgesic, or pain reducer, isn’t new, says Katerina Fotopoulou, a cognitive neuroscientist at University College London, who wasn’t involved in the study. “A lot of times people think of pain as a purely mechanical mechanism,” she says. “But we’ve known at least for a century that pain is very much influenced by social contexts. Pain is particularly influenced by implicit stuff; non-verbal communication, like touch.”
There have been multiple previous examples of skin-to-skin touch having an analgesic effect, like on babies who need medical procedures or as a therapeutic for cancer and chronic pain patients. But how does it work? The underlying physiological mechanisms of analgesic touch still aren’t completely understood, Goldstein says.
After his experience with his wife, Goldstein and his collaborators published a study that found that a toucher’s empathy levels were a factor; the more empathetic a partner was (they study was done in couples), the more effective their touch was at easing pain. In a follow-up study, they measured the physiology of both partners in a romantic couple, like heart rate and breathing. They found that the more a couple showed physiological synchrony of their breathing and heart rates, the more a partner’s touch could reduce pain. Physiological synchrony was also associated with the empathy levels in the person doing the touching.
In a new study, published this week in PNAS, they looked for this synchrony in yet another location: the brain.
Research has already shown that when you see someone else in pain, especially if that person is your partner or a friend, your brain activates in a specific way. Ilaria Bufalari, a social psychologist and social neuroscientist at the Sapienza University of Rome says that research (done by her as well as other scientists) has consistently found that when you observe pain in others, the same neural systems are activated in your brain as when you feel pain firsthand, even though the pain isn't happening directly to you. Scientists sometimes call this "brain coupling."
I ask her why we would have evolved to do that. One on hand, it can seem maladaptive if, just by looking at someone else in pain, my brain acts as if I am feeling pain too. But Bufalari says that it helps us overall as a species, because we can better understand each other.
“If I can share your negative emotion, like when you experience pain, I may help you,” she says. “This sharing may promote pro-social behavior. If I use the same neurostructures to understand your pain, this facilitates my understanding of your pain. It helps me help you. We are social animals. We live in groups, and having successful social interactions is fundamental for our surviving, even in a modern society.”
She thinks that Goldstein’s new paper is important because it sought to link these two paradigms: social touching and brain coupling. This is the first study that looked at real time brain-to-brain activity during touch and pain, or asked what brain-to-brain coupling was doing during pain relief through touch.
Goldstein's team used a method that’s relatively new, called hyperscanning, when brain activity from more than one person is monitored at the same time, in this case with EEG. They recruited twenty romantic partners (man/woman pairs), and had the female partner be the pain receiver. The couples were placed in six different situations: holding hands, sitting together without touching, or sitting in separate rooms—with a no-pain or pain version of each set up. The goal was to see if touching increased the brain coupling, and if the amount of coupling influenced how much the touching could reduced the woman’s pain.
What they found, Goldstein tells me, is that when a man held his partner’s hand while she was feeling pain, their brain-to-brain coupling did increase. And further, the more brain coupling there was, the more pain reduction the female partner felt. “We found that partners hand-holding actually can reduce pain, but the more interesting result was this correlation of the coupling–the synchrony between the brains–and the pain reduction,” he says. “Higher synchrony was related to higher pain reduction, and also, with higher partner empathy.”
It doesn’t necessarily mean that brain coupling causes the pain reduction, or vice versa—the findings can’t say anything about causality yet. But seeing that there’s a correlation between all the pieces of the puzzle: brain coupling, empathy, social touch, and pain reduction, is bringing us closer to understanding how it all works together.
Goldstein says that their findings hints at a couple of possible explanations. One is that by touching your partner, it enhances brain coupling, which increases how much your partner feels emotionally understood by another person, which can then activate reward mechanisms in the brain and lead to reduced pain. “I think touch is a tool for transferring empathy,” Goldstein says. “We transfer other emotions by touch, like love, hate, anger, so we can look at empathy as just another feeling. This may create the analgesia. We transfer empathy to our partner by touch and she feels analgesia because she feels like someone cares about her.”
Bufalari says that the next step is asking: can you modulate a relationship to increase coupling, and perhaps empathy? Brain synchronization is higher in romantic partners (which is why Goldstein focused on them), a little bit lower in friends, and then even lower in strangers. Social factors, like if you consider someone to be in your group, or if someone is the same race as you, can affect how much your brain couples with another as well. Her current work involves experiments with body illusions, where participants are made to feel another’s face belongs to them, or that they inhabit the body of someone of a different race. The research is ongoing, but she says that preliminary results are showing that doing so might be able increase the coupling, or shared activation, with another’s pain.
Fotopoulou thinks that it’s still tough to tease apart all of the factors involved in this interaction and which exact component leads to pain reduction. The person feeling pain could, via the hand holding, just be feeling supported by another, and the rest is a correlative effect we're observing. “It doesn’t necessarily mean it’s the hand holding that leads to the pain reduction,” she says. “It’s the fact that that person is interpreting the hand holding as social support.”
Goldstein agrees that context is important— and that it’s probably not just the touch by itself, but the message that the touch carries with it. He and his team have also found that a stranger’s touch is not particularly helpful. He thinks that cultural and social differences should be further studied to see if they have an effect, as well as switching the gender of the pain receiver, and testing couples that aren’t heterosexual. Regardless, we need more non-pharmacological solutions for pain, Goldstein says. Touch is perhaps not as effective as other painkillers immediately, but he thinks in the longterm, understanding how it works could be a helpful tool.
“Of course pain is so ubiquitous in medicine, and social support is a rather easy policy, and so it does imply some potential applications,” Fotopoulou says. “It shows that if nothing else, seeking a hand-hold from your partner might be a good idea when you go to the doctor, rather than going by yourself.”
Read This Next: The Family That Doesn't Feel Pain