014-16-1-2914 (to MAN.), and the John Templeton Foundation (M.A.N.). C.H. adcnowledges generous support from the ISTFELLOW program. 4. Engelman D, Fighbacher U (2009) Indirect reciprocity and strategic reputation building in an experimental helping game. Games (con &hate 67:399-407. 5. Mcquet ), Revert C,