Effects of instructions concerning ownership of a toy on preschoolers' sharing and defensive behaviors.

Sixty-eight preschoolers 30-60 months old were told that a toy belonged either to them or to the or were given no specific instructions. Their subsequent behavior with the toy was observed. When told that the toy belonged to the class, older children were more likely than younger children to share. This pattern of findings did not appear to be due to differences in understanding of possessive words; an analysis eliminating subjects who did poorly on an interview assessing comprehension of possessive concepts produced a similar pattern of results. Children of all ages defended the toy more in the yours condition than in the class condition. Girls, but not boys, exhibited more defensive behavior with age.