Pain tolerance increases during social interaction in VR

For years, virtual reality (VR) has been used in pain management for hospitalized adults and children, to take their minds off their discomfort, but typically the technology has been a solo experience for the patient.

Researchers in Cornell's Virtual Embodiment Lab, directed by Andrea Stevenson Won, associate professor of communication in the College of Agriculture and Life Sciences, have tested the effects of social virtual reality (SVR) in a trial involving both companions and strangers, and induced physical pain.

"People study social interaction for pain management, and people study virtual reality for pain management - we've kind of combining those two things, which I think is really unique," said Isabelle McLeod Daphnis '22, Virtual Embodiment Lab manager and corresponding author of "The Effects of Companionship From Strangers and Companions on Pain Thresholds in Immersive Virtual Reality: A Randomized Controlled Trial," which published Sept. 1 in Pain Medicine.

"Virtual reality is a particularly effective distractor that allows you to do a lot of interesting things with embodiment," said Won, senior author of this research. "But until we did it, nobody had ever looked at the effects of social interaction with another person in virtual reality on pain. We expected it to be additionally helpful because not only is it distracting, but it's also engaging with another person."

The study is a continuation of work published in 2020, where participants interacted with a stranger in SVR while being subjected to moderate but increasing physical pain. The new study employed the same pain-induction technique: The participant placed a hand on a thermal device, which got increasingly warmer until the individual could no longer stand it and removed their hand. Both the heat level reached (which never exceeded 50 degrees Celsius) and the person's characterization of the pain, on a scale of 1-10, were recorded.

Additionally for this study, each of the 70 participants - primarily Cornell students - were subjected to the induced pain in four randomly ordered conditions: connecting with a companion (a friend or family member) in VR; connecting with a companion via Zoom; connecting with a stranger (in this case, lab assistants) in VR; and alone in VR.

Participants generally reported a strong preference for interacting with either companions or strangers in VR over the other two study conditions, although some participants reported being able to tolerate more pain without the distraction of another individual. Some also said that the more present and involved in the VR they felt, the less pain they could tolerate.

"That's kind of the opposite of what previous studies have found," McLeod Daphnis said. "We were pretty confused by this, because usually if you're more present, you're more distracted and therefore you're not going to feel as much pain. But one possible explanation is that maybe if you're more present and engaged with the VR companion, you're holding your hand down longer."

Participants' characterization of their pain level generally matched the thermal readings, but not always, Won said.

"Some studies on pain just get people to rate their pain," she said, "and the way people rate pain after they're no longer in pain can really differ from their actual pain behavior. For our purposes, we think the behavioral measure is more useful, because in an actual hospital setting, people are going to be in pain, but we want them to notice it less."

Co-authors include Mehrnaz Sabet, M.S. '23, a doctoral student in information science; Angel Hsing-Chi Hwang, Ph.D. '23, assistant professor of communication at the University of Southern California; Hal Rives '21, currently a medical student at Temple University; Qinyue Yu '23; and Ke Wu '23.

This project - which started prior to the pandemic - employed dozens of undergraduates for both the lab work and the study participation, an important aspect of the project, Won said.

"It was a really big study," she said, "and some of the people who were on this paper are in medical school now, some have gone on to graduate programs - it was a study that brought value to a lot of people's Cornell experience. That's something that I really treasure."

This study received financial support from the President's Council of Cornell Women's Affinito-Stewart Award.