Human beings have a general tendency for reciprocity in most societies. The internalized reciprocity norm assumption suggests that reciprocity disposition would encourage reciprocity towards strangers in one-shot interactions. To verify this, we examined the predictive ability of reciprocity dispositions for giving and repaying reciprocal behaviors. A sample of college students (N = 98) participated in the reciprocity game in a laboratory, which comprised a prisoner dilemma game (PD) and dictator game (DG). The results indicated that reciprocity behavior occurred among strangers without face-to-face interactions. Reciprocity expectation predicted the choice of cooperation in the PD significantly. Positive and negative reciprocity dispositions had no effect on the strategy choice; however, they significantly predicted payoff allocation in the DG. Specifically, a higher positive reciprocity disposition led to more payoff allocation, while a higher negative reciprocity disposition led to less payoff allocation. In summary, strangers abide by the reciprocity norm, and the internalized reciprocity disposition exerts an influence on repaying behavior and accounts for some individual differences in reciprocity. These findings provide robust support for the internalized reciprocity norm assumption, and illustrate the process mechanism of human interaction among strangers. People may predict interpersonal interaction better through reciprocity dispositions and reciprocity valences. (C) 2017 Elsevier Ltd. All rights reserved.