In this article, we consider the problem of a discrepancy between, on the one hand, lay prescriptive judgments on the necessity of altruistic actions and, on the other, attributing moral worth to these actions. Based on Kantian theory of morality, we hypothesized that lay attributions of the moral worth of altruistic actions would be inversely related to normative ought-judgments according to which these actions should be performed, as having positive evolutionary-based utilitarian externalities for the actors. To test this general hypothesis, (...) we conducted two experiments using the same set of vignettes that were constructed based on systematically varying such factors as relatedness, reciprocity, the size of donation, and probability of meeting in the future. The results provide overall confirmation of our assumption, as evaluative judgments about the moral worth were inversely dependent on information provided about possible contributions from such consequentialist, payoff-based mechanisms as kinship and expected reciprocity, while prescriptive judgments were positively influenced by such information cues. (shrink)