A study says when a child says 'mine', it may mean more than possessiveness: Why sharing takes time

Picture a two-year-old pushing a toy truck across the floor. Another child reaches for it. “Mine!” The truck disappears behind the first child’s back. An adult says, “Be nice. Share.” One child wants a turn. The other refuses.

Research suggests a fuller picture. Children are learning what ownership means and how to respond to someone else’s needs. Knowing a sharing rule can also differ from choosing to follow it. One toy dispute cannot explain a child’s whole character.

What did the study on toddlers and sharing find?

Psychologist Celia A. Brownell and colleagues at the University of Pittsburgh studied 51 children aged 18 or 24 months. Published in Child Development in 2013, their research gave children opportunities to share toys or food with an adult playmate.


The older toddlers shared more readily. Younger toddlers also shared when they had repeated opportunities and enough help understanding what the adult wanted.

Children with better ownership understanding tended to share more, even after accounting for age and language ability. Understanding “mine” was compatible with generosity.

Why can understanding ownership matter for sharing?

Ownership helps children distinguish what belongs to them from what belongs to someone else. Giving another person access to an object involves more than moving it across the floor. The child must understand the social situation.

Brownell’s study suggests that ownership knowledge can develop alongside sharing. It does not establish that teaching the word “mine” causes generosity. The experiment also involved a cooperative adult and plentiful resources. A dispute over one treasured truck may feel different.

Imagine the child is halfway through building a pretend road. Handing over the truck means interrupting that game. The cost of sharing depends on what is being shared and what the child is doing with it.

Can children know what is fair but still refuse to share?

Yes. Psychologists call this a “judgment–behaviour gap.” Craig E. Smith and colleagues, including psychologist Peter R. Blake, investigated the gap in research published in PLOS ONE in 2013.

Children aged three to eight could say that stickers should be shared equally. Younger children nevertheless kept more for themselves. Equal sharing emerged among the seven- and eight-year-olds in that task.

The researchers also tested inhibitory control, meaning the ability to hold back an immediate response. It did not explain the age-related change in sharing.

Simply saying younger children lack willpower would miss the finding. Knowing the rule is one part. Giving it enough importance when your own stickers are involved is another.

Why might having a choice affect generosity?

Psychologists Richard Ryan and Edward Deci’s “self-determination theory” highlights autonomy in motivation. Autonomy means feeling that an action is willingly chosen. It does not mean having permission to do anything.

Choice may matter when children practise generosity. Handing over a toy under instruction and choosing to offer it can look identical. The child’s experience of the action may differ.

The theory offers context for understanding motivation. It cannot tell us exactly why an individual child refuses a particular request.

What happened when preschoolers could choose to share?

Psychologists Nadia Chernyak and Tamar Kushnir tested choice directly in a 2013 study published in Psychological Science.

Some three- and four-year-olds could choose to give away something they could keep. Others chose whether to give an item that would otherwise be discarded. Another group followed instructions to give.

Later, children who had faced the meaningful, costly choice shared more with a new recipient. The researchers proposed a “prosocial-construal hypothesis.” In plain language, choosing to help may encourage children to see themselves as someone who helps. The finding concerns sharing under those experimental conditions. It does not show that adult guidance is harmful.

How can adults help children practise sharing?

The early childhood organisation ZERO TO THREE recommends helping children with turn-taking and acknowledging their feelings. Sometimes, allowing a longer turn is reasonable. The waiting child can try another activity until the toy becomes available.

A timer may help when an open-ended turn is impractical. Adults can also make the situation clear: “You are playing with the truck. Your friend would like a turn.” Stopping grabbing remains important. Understanding a refusal does not require accepting aggression.

Back on the floor, the truck dispute becomes an opportunity to teach. Help both children work out what happens next.