Upstream or downstream reciprocity: which matters more for sharing expectations and behavior in 4- to 5-year-old children?

Recent research suggests that the sharing behavior of young children is influenced by indirect reciprocity. This study investigated how upstream reciprocity (the sharer's prior experience of being shared) and downstream reciprocity (the recipient's previous sharing behavior) influence sharing expectations and behavior in 4- to 5-year-olds. In Experiment 1, children acted as 'observers', predicting the number of stickers 'sharers' would allocate to 'recipients' with previous generous or stingy behavior. The sharers had previously experienced being shared with generously or stingily. In Experiment 2, children acted as 'sharers', directly experiencing being shared with generously or stingily before allocating stickers to 'recipients' with previous generous or stingy behavior. The results indicated that young children's sharing expectations and behavior are influenced by both upstream and downstream reciprocity, with the latter potentially being of greater significance for sharing behavior.