Children as young as age three are able to make judgements about who owns an object based on its location, according to a study from the University of Waterloo.

The findings also show that children can sense an item's ownership without seeing someone interact with it. They intuitively know who owns an item, even if their parents have not pointed that out to them.

"Previous research looked at how children understand the ownership of an object after someone has interacted with it or talked about it. But in the real world, we're surrounded by objects that no one is interacting with or near, and it's still important to know who owns what," says Brandon W. Goulding, lead author and PhD candidate in the Department of Psychology. "One way we can do that is to realize a whole area is under someone's ownership, and because of that, we can infer everything in that area is owned by that person. That way, you don't have to worry about learning hundreds of individual object-owner relationships."

The study involved children ages three to five years old. In a series of experiments, participants were shown slides that depicted two yards divided by a roadway and told one house belonged to a person and the other to his neighbour. Each yard contained various objects such as flowers or a lawnmower. Without being told any information about the objects, the children were asked to determine whether they belonged to the person or his neighbour.

Children of all ages in the study could infer that the person owned the objects in his yard, but not objects in his neighbour's yard. Participants were still able to correctly infer ownership when the person was moved across the street to visit his neighbour, suggesting the proximity of the owner to his territory wasn't key to their understanding. Furthermore, older children are able to consider history and past events when determining ownership. For instance, when a dog brings an object into the yard, the five-year-olds knew the ball likely belonged to someone else.

"People are often concerned about their children's possessiveness -- the 'gimmes' -- but I think they often have adult-like intuitions about ownership," said Ori Friedman, co-author and professor of psychology. "Often, we assume we have laws that legal experts understand, and people learn them and pass them on. However, there could be another way to look at it: that our psychology shapes our culture and laws. Children's judgements are strikingly in line with the law, yet they are likely unaware of such legal conventions," said Friedman.

Overall, the study suggests that children's judgements are more in line with adults than we thought.

The full study "The development of territory-based inferences of ownership" appeared recently in the journal Cognition.