McEwan, S., Pesowski, M. L., & Friedman, O. (2016). Identical but not interchangeable: Preschoolers view owned objects as non-fungible. Cognition, 146, 16–21. http://doi.org/10.1016/j.cognition.2015.09.011
This is another great article by Ori Friedman’s team. They did three experiments to find out whether children see owned objects as fungible (i.e., as replaceable or interchangeable). In Experiment 1, children considered an agent who takes one of two identical objects and leaves the other for a peer. When considering a scenario where a boy took one of two identical objects home, and left the other for a girl, preschoolers viewed his behavior as more acceptable when he took his own item, rather than the girl’s.
In Experiment 2, children considered scenarios where one agent took property from another. When considering a scenario where a boy deprived a girl of her balloon, preschoolers judged it acceptable for the girl to take back her own balloon; but they judged it unacceptable for her to take the boy’s balloon, even though it was the only balloon available to compensate her.
Finally, in Experiment 3A and 3B, children considered scenarios where a teacher could give a child either of two objects to play with—an object that the child had recently played with, or another object that looked the same. When considering a scenario where a teacher could give a boy one of two identical-looking balls to play with, preschoolers were more likely to say she should return the ball that the boy had previously played with when it belonged to him, compared with when it was her own.
These findings indicate that children see property as non-fungible.
Previous studies showed that children at these ages show concern for owners’ rights to an object. McEwan et al.’s findings extend knowledge by showing that these concerns persist even when an identical replacement is available to the other. The fact that children at these ages already show intuitions of non-fungibility indicates that such intuitions are an early development, and perhaps foundational in people’s reasoning about ownership. People view ownership as granting people rights to particular objects (i.e., rather than to objects of a certain type).
These are all very relevant and important findings that add detail to current knowledge about the development of ownership.
One conceptual doubt. The fact that children say that it’s not ok to take the perpetrator’s object may not mean that children literally see identical objects as interchangeable. In my opinion, this last statement presupposes a “physicalist” view of the world, understood as a collection of free floating objects with certain physical characteristics that make them different or identical, and placed in certain positions within a 3D space. An alternative view is that children, when they respond to the interviewer, are judging the actions and intentions of the characters, in the context of a social situation that includes objects. And, as Gelman says, objects have histories. So children may think something like “it’s not ok to take someone else’s property even if they took yours first”. It is also more likely that they think in terms of particular objects, not in terms of classes or categories of objects. So the concepts of “identical” or “interchangeable” may not play a role in children’s reasoning. Also, the difference between responses to the balloon situation and the cookie situation might be due to the fact that children take into account the actions of the perpetrators, and perhaps her intentions. It’s not the same popping a balloon accidentally than eating a cookie purposefully.