Laura Cirelli recently spent a lot of time bouncing with babies. Over the course of two experiments in a lab at Ontario’s McMaster University, she strapped dozens of 14-month-olds to her fellow psychology grad student Kathleen Einarson, cranked up a MIDI version of “Twist and Shout,” then dipped to the beat as Einarson bopped the babies in front of her.
The point of the exercise was to give the babies a sense of moving in rhythm with Cirelli—dancing with her before they could fully walk by themselves. More and more research has shown that people who act in-sync cooperate better and even like each other more, so Cirelli, a lifelong dancer and one-time summer daycare instructor, wanted to know just how early in life rhythm-inspired affiliations can form.
“Moving with people is a natural part of our musical experience in a social context,” she says. “Studies already have shown that babies have the urge to move to music, so we wanted to see if there’s a social element to their experience of it, too.”
During their experiments, Cirelli and Einarson wore headphones that tapped out beats for them to bounce to as the music played, allowing them to move in-sync with each other and the music. In other trials, they bounced out-of-sync. Once the song ended, they brought each baby to a foam floor mat, where Cirelli ran three sneaky tests: She dropped a marker while drawing a picture for the child, dropped a clothespin while hanging dishcloths, and dropped a paper ball while placing it in a bucket. Each time, she timed how long it took the baby to return the object to her, if the baby did at all.
The two researchers then scored the babies’ helpfulness as a way of gauging their feelings toward Cirelli. They found that, in line with adult behavior, the kids who bounced in-sync with her were more willing to give her a hand. Out-of-sync bouncers helped out a little more than 30 percent of the time, whereas in-sync bouncers helped in just under half of the tests.
“There’s really something about interpersonal synchrony that drives our sense of affiliation, even at an early age,” Cirelli says. While it’s still unclear why—one theory suggests that watching someone move at the same time as you automatically makes you feel more similar to them—Cirelli believes her results, which were published this month in Developmental Science, underscore just how fundamental dancing is to cementing social bonds.
The study does not suggest music itself has intrinsic bonding power, Cirelli notes. Babies were more helpful whenever they bounced in-sync with her, regardless of whether or not they bounced to the song’s actual beat. But that’s no knock against music’s social importance, she contends. “It might not be necessary, but music is certainly the most prevalent context where moving together in synchrony with others just happens automatically,” she says. “What we’re finding is that it’s not just about having music playing in the background. Its effects come with active engagement.”