Can empathy pass from one person to another through the simple act of hand-holding? According to a new study - Yes.

During times of hardship, holding hands with loved ones may not only synchronize breathing and heartbeats but also brain wave patterns.

In the new study, researchers from the University of Colorado Boulder and the University of Haifa found that the more empathy one feels for their partner in pain, the more their brain waves synchronize and provide pain relief. In fact, brainwave synchronicity was apparent with even just being in each other's presence, with or without physical contact.

"This paper illustrates the power and importance of human touch," says Pavel Goldstein, leading author of the study who is a postdoctoral pain researcher in the Cognitive and Affective Neuroscience Lab at CU Boulder. He explains how the idea for the study came to him after the birth of his daughter when he noticed how holding his wife's hand helped in easing her pain.

"My wife was in pain, and all I could think was, ‘What can I do to help her?’ I reached for her hand and it seemed to help," Goldstein said. "I wanted to test it out in the lab: Can one really decrease pain with touch, and if so, how?"

Twenty two heterosexual couples who were between the ages of 23 and 32 and had been together for at least a year were participants in the study. Researchers asked them to undergo a variety of two-minute scenarios (sitting together not touching; sitting together holding hands, and sitting in separate rooms) while electroencephalography (EEG) caps measured their brainwave activity.

One scenario involved women being subjected to the mild pain of heat on their forearm for two minutes as their partners either held their hands or sat at a distance with no physical contact. Findings of the study revealed that holding hands during pain increased the 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."

The paper matched the findings of a previous study from 2017 which showed how heart rates between partners fell into synchronization when they touched, and particularly when one partner was in pain. More studies have begun exploring the phenomenon of "interpersonal synchronization", which is the act of people physiologically mirroring another in their presence. According to previous research, physical touch can make people feel more understood, activating pain-killing reward mechanisms in the brain. 

The male partner also measured considerably higher levels of empathy during the coupled brain activity. "It appears that pain totally interrupts this interpersonal synchronization between couples and touch brings it back," said Goldstein, adding that the power of hand-holding cannot be underestimated. "You may express empathy for a partner's pain, but without touch, it may not be fully communicated."

On average, the intensity of pain is said to be reduced by 34% when holding hands. The study, however, did not explore the effect in homosexual couples or non-romantic partners.