We all know the familiar refrain of “That’s miiiiiiine!!!”—squealed by preschoolers on every block when a neighbor, sibling, friend, or mere passerby picks up the child’s toy. Understanding ownership, as it pertains to objects, starts remarkably early in human development with studies showing its emergence by the late toddler and early preschool years. As children get older they come to understand the true nuances of ownership—like the fact that usually the person who buys an object owns it, but not always. If the purchaser gives the object as a gift, now the recipient has all rights to the object. He can even destroy it without asking the purchaser’s permission. Children understand these complicated cases by late preschool.

My lab has recently begun investigating a new question about ownership understanding—when children begin to understand that ownership applies not only to objects, but to abstract ideas. As adults we are governed by a very complicated set of laws regarding ideas. Certain rights and regulations apply to scientific innovations (patents) and others to artistic works (copyright). But my lab is less interested in when children learn these specific laws, rather when they start to feel that sense of injustice they feel when someone takes their truck, in a situation in which someone takes their original joke or story or song.

Our first test of this question presented children with a puppet show in which one puppet looked at another puppet’s drawing and then either copied the same thing or made something new. The results were remarkably consistent. Six-year-olds shouted out in protest, “He’s copying!” while 4-year-olds said things like “huh, he drew the same thing!” When asked to rate the “copier,” 6-year-olds penalized him, while 4-year-olds thought he was perfectly fine. These findings suggested to us that 6-year-olds have a sense of ownership over ideas, while 4-year olds don’t, but we wanted to understand why.

We next designed a set of studies to ask when children first come to see ideas as important and valuable—thinking this might be necessary in order for children to think copying ideas is bad. We were inspired by everyday life in a research lab. In the lab, very often the principal investigator (PI) or lab director is a faculty member or high level researcher involved in the development of an experiment. He or she usually develops these ideas in combination with postdoctoral fellows or grad students who then perform the actual experiment/research with a team of undergraduate students and lab techs. The latter folks end up doing much of the manpower to the idea through. However, when the work is ultimately published, it is the PI whose name is listed amongst the authors, with undergrads and lab techs often left off from the author list entirely. This is not deceit or lack of recognition of hard work, rather the norm—we value the idea generation more than the labor.

In our study, children were told about an art project that was completed by two people. One person came up with the idea for the art project and the other person did the actual labor to see it completed. Our question to children was—who should get to take the art work home? Six-year-olds, much like adults in the case of scientific research, go with the idea creator. Four-year-olds, however, were unsure—some picked the idea creator, others the laborer. This divergence by age was further supported by a task in which children themselves either came up with the idea for, or labored on, an art project. Six-year-olds thought the picture they designed, rather than the picture they worked on, should be theirs, while four-year olds, weren’t quite sure.

What’s more, other work has suggested that by age six children apply a wide range of other principles of ownership to ideas. For example, they think that the person who first solved an intellectual puzzle or came up with a novel story is its owner, rather than someone who tried to solve the puzzle or come up with a story first, but who subsequently failed to do so. They also recognize that stealing someone’s idea does not make you the idea’s owner.

Together all of this work suggests that by age 6 years, children have a rather sophisticated understanding of ideas. They think people can own them. They think this ownership should be respected and those who copy or take others’ ideas are bad. But unlike physical property ownership, the seeds of this tendency do not emerge as early. Four-year-olds are fairly clueless about idea ownership. When ideas are pitted against labor, they aren’t quite sure which is more important. They notice when people make the same art, but don’t fault the copier.

So next time you hear that familiar refrain—“That’s MINE!” coming from a young preschooler—you can be fairly sure someone stole their toy or their food, and not their joke, story, or song.

To follow Kristina Olson's research, follow her lab's twitter account:@SCDlab

Copyright Kristina Olson 2013

Recent Posts in Developing Minds

Nonverbal Communication in Infancy

Why and when infants point

When Does Bilingualism Help or Hurt?

The effects of bilingualism on children’s cognition.

Selling Bridges to Babes

Gullibility in childhood

When Praise Backfires

More positive praise isn't always better.

Children’s Understanding of Death and the Afterlife

Evidence for “natural-born dualism”?

The Mysterious Allure of the Frilly Pink Dress

The latest research on gender appearance rigidity