Mine or yours? Development of sharing in toddlers in relation to ownership understanding.

To examine early developments in other-oriented resource sharing, fifty-one 18- and 24-month-old children were administered 6 tasks with toys or food that could be shared with an adult playmate who had none. On each task the playmate communicated her desire for the items in a series of progressively more explicit cues. Twenty-four-month-olds shared frequently and spontaneously. Eighteen-month-olds shared when given multiple opportunities and when the partner provided enough communicative support. Younger children engaged in self-focused and hypothesis-testing behavior in lieu of sharing more often than did older children. Ownership understanding, separately assessed, was positively associated with sharing and negatively associated with non-sharing behavior, independent of age and language ability.