Consistent kindness: Money allocation and kind act decisions are regulated by a ‘welfare trade-off ratio’

Is kindness regulated by a cost-benefit ratio? Previous research suggests that money allocation decisions are regulated by a ‘welfare trade-off ratio’ (WTR) that reflects the weight attached to the actor’s welfare relative to the recipient’s welfare. Here we replicate this research, and extend it by creating a new measure— The Kindness Questionnaire —which asks which real-world acts of kindness, previously rated for cost and benefit, participants would perform for others. In Study 1 ( n = 6,601) money allocation (MA) and Kindness Questionnaire (KQ) decisions for family, friends, colleagues and strangers were highly consistent with an underlying WTR (~92%); more consistent than would be expected by chance; and generally more consistent than with cost or benefit alone. WTRs were high (~0.81); and, for money allocation, declined with social distance. In Study 2 ( n = 8,492) MA and KQ decisions for neighbors were highly consistent with an underlying WTR (~89%); more consistent than would be expected by chance; and generally more consistent than with cost or benefit alone. WTRs were high (~0.75). In both studies, The Kindness Questionnaires showed good convergent, divergent and incremental validity. These studies corroborate ‘welfare tradeoff ratio’ theory, establish proof of principle for a new way of measuring kindness, and provide new tools for measuring kindness to colleagues, strangers and neighbors.