Want your heart and your lover's to beat as one? Well, it’s simple: Just have one of you walk over burning coals. In a recent study, researchers monitored people’s heartbeats while they watched their friends or relatives take part in a fire-walking ritual, National Geographic reports. They found that the heartbeats of both the onlooker and the fire walker changed at the same times, though they did not quite match each other perfectly.
“We can find markers of emotional connectedness in bodily measures as well—it's not just a cognitive effect,” says one of the study’s co-authors. Another psychologist says the finding reinforces a law of nature, which states that when disparate rhythms meet, they will coordinate. “We like to think … we’re this isolated being,” he says. But this study has “demonstrated this is not the case.”