Reciprocity in children's self-disclosures is often examined in children's friendships. It has been shown that children's understanding of friendship involves sharing secrets with another person. This mutual exchange of sharing secrets could be the norm of reciprocity, in which individuals disclose because it is a social norm. This norm of reciprocity is shown to begin occurring for children in sixth grade. Sixth graders are able to understand the norm of reciprocity because they realize that relationships require both partners to cooperate and to mutually exchange secrets. They realize this because they possess the cognitive ability to take another person's perspective into account and are able to understand a third person's views which allows them to view friendships as an ongoing systematic relationship.