First possession: an assumption guiding inferences about who owns what.

How do we determine who owns what? This article reports evidence indicating that we typically assume that the first person who possesses an object is its owner. In Experiments 1 and 2, participants read cartoons in which two children each take a turn playing with a toy. Participants selected the character who first possessed the toy when judging who owned it, but not when judging which character liked it more. In Experiment 3, participants read stories based on the Pierson v. Post (1805) property law case. In line with the appellate court's ruling in that case, participants selected the character who first captured and possessed an animal as its owner over another character who had pursued it earlier. Together, these findings provide evidence for an assumption that specifically guides our reasoning about ownership and that may lead everyday intuitions about property to be generally consistent with property law.