Researchers may have pinpointed the exact moment when we start to transition away from carefree kids, unafraid to perform in public or of what others may think of us.

Many of us go through a transformation from enthusiastic children eager to show off—whether a song, a new dance move, or the number of animals we can name—to brooding teenagers who want the contents of our mind to remain an eternal secret. The most common explanations for this shift are the ostensible changes that occur during the transition to adolescence, such as increased conformity to peers and a focus on social status. But now researchers have found evidence that this shift begins even earlier than previously believed, and that it may be driven by a crucial cognitive development that’s arguably the basis of all human social interaction.

The new study (PDF), which was conducted by Lan Chaplin of the University of Illinois-Chicago and Michael Norton of Harvard, examined how the development of Theory of Mind (TOM) influences a child’s desire to perform in public. TOM refers to the understanding that other people can have mental states that are different from our own—that they have their own mind, and that it operates independently of others. It allows us to make sense of social norms and the intentions, beliefs, and desires of others.

If children as young as four—who don’t have to deal with puberty or demanding family relationships—are motivated to alter their behavior based on the perceptions of others, imagine how hard it is for a 13-year-old to figure out how to behave.

In the classic TOM experimental paradigm children are told or shown a story in which someone places an object (a cookie, for example) in one location and then leaves the scene. While they’re gone, a second person moves the object to another location. Children are then asked where the first person will look for the object when they return. Before the age of four most children are unable to separate their own knowledge from that of the first person in the story, and thus they answer with the object's current location. Once TOM develops—typically between the ages of four and six—children are much more likely to correctly answer with the object’s original location.

Chaplin and Norton hypothesized that because TOM allows us to understand that the thoughts of others may differ from our own, it may also represent the beginning of our ability to believe that others may not think of us as fondly as we do ourselves. Their study examined over 150 children between the ages of three and 12 from eight summer camps in the Northeast. Participants completed a measure of TOM (a more difficult scenario was used for the older children), and were asked to perform two of four tasks in front of the experimenter. Two of the tasks were “performance” tasks—singing a song or performing a dance of the child’s choosing—and two were non-performance tasks—circling or coloring shapes on a worksheet.

After controlling for age, the researchers found that the more a child had developed TOM the less desire he or she had to publicly sing or dance. It seems that once children are able to understand that other people have unique mental states and beliefs, they can envision that those people may not find their performance all that exciting. At least for those of us who haven’t made fools of ourselves on a performance-based reality television show, the belief that somebody may view our public performance unfavorably is a conspicuous aspect of our daily behavioral regulation. But Chaplin and Norton’s study suggests that thanks to the development of TOM, this can occur as early as age four.

If you’re a parent attempting to vicariously achieve musical fame through your child, the key question is whether anything can be done to preserve the penchant for song and dance. One possibility is that an increase in positive feedback during the time TOM develops could mitigate the decline in the desire to perform. Children see themselves in a positive light, and so the idea that other people are capable of seeing them differently allows for the idea that others may see them in a negative light. Providing positive feedback communicates that even though people are capable of seeing the child's performance in a different, negative light, they often will have the same perception as the child—that the child’s performance was great. Ideally, positive feedback will allow a child to walk away with the belief that even though it’s possible for other people to see them differently, this is a relatively rare occurrence. Future research could explore whether positive feedback has stronger long-term effects when aligned with TOM development.

Even if you have no theatrical aspirations for your child the study still highlights some interesting things about the human mind. First, damn is it hard to be a teenager. If children as young as four—who don’t have to deal with puberty, a social hierarchy, or demanding family relationships—are motivated to alter their behavior based on the potential perceptions of others, imagine how hard it is for a 13-year-old to figure out how to behave.

The study is also a reminder that even our most important cognitive developments have drawbacks. It’s no big deal if TOM pushes a child to avoid dancing in public, but there will be legitimate costs if, for example, it leads a talented adult to avoid sharing an idea or pursuing an invention. And there is evidence that TOM can make people more sensitive to criticism, although whether or not the consequences of such sensitivity are good or bad may depend on the person or the situation.

Like our tendency to favor people who are members of our own group—which contributes to both the conflict and stability in our world—TOM can seem like a mixed bag. But despite the stumbling blocks it may occasionally create, TOM has played a key role in the growth and cohesion of modern social groups. So if your child suddenly decides he doesn’t want to dance anymore, just remind yourself that the same process behind his newfound stage fright is what might one day allow him to understand your seemingly out-of-step opinions on sex, drugs, and homework.