Many observers of experimental games have interpreted the fact that people sometimes sacrifice material gain in favor of moral sentiment as an indication of irrationality, the term 'rationality' being misused as a synonym for "consistent pursuit of self-interest." But subjects appear to be no less rational when deciding to cooperate and punish than when they compare prices to decide what to cook for dinner. This suggests that the preferences that lie behind their social behavior are consistent with the basic axioms of rationality, namely transitivity (consistency) and completeness
Sid 32 i Bowles, S., & Gintis, H. (2011). A cooperative species. Princeton University Press.