title: Uncalculating cooperation is used to signal trustworthiness.
abstract: Humans frequently cooperate without carefully weighing the costs and benefits. As a result, people may wind up cooperating when it is not worthwhile to do so. Why risk making costly mistakes? Here, we present experimental evidence that reputation concerns provide an answer: people cooperate in an uncalculating way to signal their trustworthiness to observers. We present two economic game experiments in which uncalculating versus calculating decision-making is operationalized by either a subject's choice of whether to reveal the precise costs of cooperating (Exp. 1) or the time a subject spends considering these costs (Exp. 2). In both experiments, we find that participants are more likely to engage in uncalculating cooperation when their decision-making process is observable to others. Furthermore, we confirm that people who engage in uncalculating cooperation are perceived as, and actually are, more trustworthy than people who cooperate in a calculating way. Taken together, these data provide the first empirical evidence, to our knowledge, that uncalculating cooperation is used to signal trustworthiness, and is not merely an efficient decision-making strategy that reduces cognitive costs. Our results thus help to explain a range of puzzling behaviors, such as extreme altruism, the use of ethical principles, and romantic love.
authors.affiliation: Department of Psychology, Yale University, New Haven, CT 06511; jillian.jordan@yale.edu david.rand@yale.edu.
authors.forename: Jillian J
authors.initials: JJ
authors.lastname: Jordan
authors.affiliation: Program for Evolutionary Dynamics, Harvard University, Cambridge, MA 02138.
authors.forename: Moshe
authors.initials: M
authors.lastname: Hoffman
authors.affiliation: Program for Evolutionary Dynamics, Harvard University, Cambridge, MA 02138.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Nowak
authors.affiliation: Department of Psychology, Yale University, New Haven, CT 06511; jillian.jordan@yale.edu david.rand@yale.edu.
authors.forename: David G
authors.initials: DG
authors.lastname: Rand
mesh_terms: D002755:Choice Behavior / Q000502:physiology*; D003299:Cooperative Behavior; D003657:Decision Making; D005716:Game Theory; D005717:Games, Experimental; D006801:Humans; D007398:Interpersonal Relations; D008960:Models, Psychological; D035502:Trust / Q000523:psychology*
keywords: decision-making; experimental economics; moral psychology; reputation; social evaluation