“But with such readings difficult to obtain, they settled on heart rate, strapping monitors on fire-walkers and spectators to see whether the rates of spectators increased like those of people actually walking barefoot on hot coals. […]
The researchers wanted to investigate what draws people to communal rituals like fire-walking.
“There’s the idea about rituals that they enhance group cohesion, but what creates this group?” Ms. Konvalinka said. “We figured there was some kind of autonomic nervous system measure that could capture the emotional effects of the ritual.”
The results surprised them. The heart rates of relatives and friends of the fire-walkers followed an almost identical pattern to the fire-walkers’ rates, spiking and dropping almost in synchrony. The heart rates of visiting spectators did not. The relatives’ rates synchronized throughout the event, which lasted 30 minutes, with 28 fire-walkers each making five-second walks. So relatives or friends’ heart rates matched a fire-walker’s rate before, during and after his walk. Even people related to other fire-walkers showed similar patterns.
Experts not involved in the study said despite the small number of participants, the results were intriguing. They build on research showing heart rates of fans of team sports surge when their teams score, and on studies demonstrating that people rocking in rocking chairs or tapping their fingers eventually synchronize their movements.”
see article in NYT