In addition to gender-related differences, age-related differences may also impact upon the quantity and quality of children's friendships, leading to differences in the nature and extent of their influence. Developmental differences among 3–5-year-olds can be considerable and may thus have an impact on the extent to which peers reinforce or shape behavior. With this in mind, the current study included age as a potential moderator of the link between friends’ and children's own social behavior.