Playing by the rules: self-interest information influences children's trust and trustworthiness in the absence of feedback.

•We tested whether self-interest cues influenced people’s trust and trustworthiness.•Adults and children flexibly used self-interest cues when choosing to trust others.•Adults and children also readjusted their trustworthiness to match self-interests.•Children were less trusting of informants with common interests than were adults.•Children showed a more mature understanding in behavioral versus verbal responses.