Upstream reciprocity in the battle of good vs evil

Upstream reciprocity, known colloquially as “pay-it-forward”, is reciprocating an act of kindness to an unrelated third party. “Negative upstream reciprocity” means reciprocating an unkind act to an unrelated third party. The present research proposes an experimental test of upstream reciprocity and contrast between its two forms. Survey questions on trust and gratitude complement the study. Results show evidence of positive upstream reciprocity but against its negative counterpart. Subjects pay forward even after being helped by a computer, indicating that the effect is self-referential. Results extend psychological theories of gratitude by showing that gratitude functions as a “buffer” or “regulator” against the impact of help or harm in social interactions. Results align with the social interaction principles described by Adam Smith in The Theory of Moral Sentiments, informing our understanding of the observed behavior.