Cognitive foundations for helping and harming others: Making welfare tradeoffs in industrialized and small-scale societies

For many abilities, such as vision or language, our conscious experience is one of simplicity: We open our eyes and the world appears; we open our mouths and grammatical sentences tumble out. Yet these abilities rely on immensely complex, unconscious computations. Is this also true of abilities related to cooperation or competition, like deciding whether to share food or spread gossip? We tested whether decisions like these are guided by precise psychological variables, called welfare tradeoff ratios. Welfare tradeoff ratios summarize information about multiple sources of social value (such as whether a specific other person is kin or is generous with the self) along with information about the situation (such as what's at stake or who else is watching). We evaluated these hypothesized variables in four societies: among college students in the USA and Argentina and among two groups of Amazonian forager-horticulturalists, the Shuar of Ecuador and the Tsimane of Bolivia (ns = 167, 131, 73, 23). In all societies people made a series of hypothetical decisions where they had to weigh help or harm for themselves versus others. We found strong evidence that people trade off their welfare for others with consistency—a signature of decisions being guided by precise variables in the mind. We also found evidence in three of the societies that people discriminate among different categories of others in their welfare tradeoffs (e.g., friends versus acquaintances). Although most decisions about helping or harming feel simple and intuitive, they appear to be underwritten by precise computations.