Picture two birthday parties: one for 4 year olds, and one for 14 year olds. The former conjures kids bellowing “Happy Birthday” and putting their left feet in during the “Hokey Pokey”; the second conjures slump-shouldered teens huddled in corners furtively glancing at each other—even as loud music blares in the background. Why the difference? Our research suggests that the process of kids losing the joy of singing and dancing is intricately linked to a crucial development in their understanding of other people. In short, as soon as we are able to understand that others can have opinions of their own—and might not share our opinion of our killer dance moves—we lose our performance mojo.

We tested the link between the ability to understand the minds of observers and willingness to perform with a test of one hundred fifty-nine children ranging in age from 3 to 12 years old. We first gave each child four options in random order: sing a song of their choosing, perform a dance of their choosing, circle red shapes on a page, or color in a square. Children had to select two of the four options to complete in front of us—right then and there. The first two tasks were our performance tasks, made even more difficult by the fact that the singing and dancing had to be completed without any musical accompaniment. The second two tasks were our “control” tasks, which we made deliberately boring to see if older kids would still choose these over the terror of performance.

The differences between kids of different ages were surprising even to us. Whereas some 31% of 3-year olds chose to both sing and dance, not a single child aged 11 or 12 did. Or put another way, while just 6% of 3- and 4-year-olds chose to avoid both singing and dancing, nearly 75% of 11- and 12-year olds chose to avoid both. Yes, 12-year olds would rather circle and color shapes, tasks they typically shun as being for little kids, than take the risk of breaking out the Macarena or belting out Taylor Swift.

Why such a change in preferences? We next measured children’s awareness that others might be judging their performance, using a task that measures “Theory of Mind”—or our ability to understand that others have minds and opinions that differ from ours. Children heard a story about a dolly named Sally who places a toy car in a basket and leaves the room; another doll, Anne, then moves the car to a box without Sally seeing the move. Children are then asked where Sally will look for her doll when she comes back. Those with Theory of Mind understand that Sally will look in the basket, because they understand that they have knowledge that Sally does not. Those lacking Theory of Mind guess that Sally will look in the box, because they lack the ability to realize that Sally does not share their knowledge and view of the world.

Who guessed right? Older children, overwhelmingly. 3- and 4-year olds were very unlikely to guess correctly, while 11- and 12-year olds nearly always got it right. Most importantly, this developmental increase in Theory of Mind was strongly and negatively correlated with children’s desire to sing and dance: the higher children scored on our Theory of Mind test—the more children understood that others can have a different opinion of their abilities—the more likely they are to refuse to perform. And this trend held among our youngest participants: 3- and 4- year olds with a more developed Theory of Mind were more likely to avoid singing and dancing.

Our data rule out a salient alternative explanation for our pattern of performance avoidance, one familiar to anyone interacting with socially awkward teens or tweens: as children enter puberty they experience a host of changes that decrease their desire to perform. However, our results show that the shift away from performance begins as early as age 4—years before children enter puberty—suggesting that these changes associated with puberty are unlikely to account for our results.

While our investigation stopped with 12-year olds, our casual observation of adults suggests that the tendency to refuse to sing and dance lingers long after adolescence (especially in the absence of alcohol). What are we forgoing with our refusal to perform? Research shows that activities like singing and dancing are associated with benefits for health and happiness, but even more qualitatively: have you ever seen a group of happier individuals than 4-year olds belting out “Let It Go” from the Disney movie Frozen? Our results suggest that grown-ups could learn something from children by letting it go ourselves and getting out on the dance floor.

Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook. Gareth, a Pulitzer prize-winning journalist, is the series editor of Best American Infographics and can be reached at garethideas AT gmail.com or Twitter @garethideas.