Do we praise altruistic acts because they produce socialbenefits or because they require a personal sacrifice? Onthe one hand, utilitarianism demands that we maximize thesocial benefit of our actions, which could motivatealtruistic acts. On the other hand, altruistic acts signalreputation precisely because personal sacrifice is a strong,costly signal. Consistent with the reputational account,these studies find that in the absence of reputational cues,people mainly rely on personal cost rather than socialbenefit when evaluating prosocial actors (Study 1).However, when reputation is known, personal cost acts as amuch weaker signal and play a smaller role in moralevaluations (Study 2). We argue that these results have far-reaching implications for the psychology and philosophy ofaltruism, as well as practical import for charitable giving,particularly the effective altruism movement.

Story-telling helps to define the human experience. Donarratives also inform our predictions and choices? Thecurrent study provides evidence that they do, using financialdecision-making as an example of a domain where,normatively, publicly available information (about the pastor the future) is irrelevant. Despite this, participants usedpast company performance information to project futureprice trends, as though using affectively laden informationto predict the ending of a story. Critically, these projectionswere stronger when information concerned predictionsabout a company’s future performance rather than actualdata about its past performance, suggesting that people notonly rely on financially irrelevant (but narratively relevant)information for making predictions, but erroneously imposetemporal order on that information.

Mathematicians often describe arguments as “beautiful” or “dull,” and famous scientists have claimed that mathematical beauty is a guide toward the truth. Do laypeople, like mathematicians and scientists, perceive mathematics through an aesthetic lens? We show here that they do. Two studies asked people to rate the similarity of simple mathematical arguments to pieces of classical piano music (Study 1) or to landscape paintings (Study 2). In both cases, there was internal consensus about the pairings of arguments and artworks at greater than chance levels, particularly for visual art. There was also some evidence for correspondence to the aesthetic ratings of undergraduate mathematics students (Study 1) and of professional mathematicians (Studies 1 and 2).

Moral judgment depends upon inferences about agents’ beliefs, desires, and intentions. Here, we argue that in addition to these factors, people take into account the moral optimality of an action. Three experiments show that even agents who are ignorant about the nature of their moral decisions are held accountable for the quality of their decision—a kind of behaviorist thinking, in that such reasoning bypasses the agent’s mental states. In particular, whereas optimal choices are seen as more praiseworthy than suboptimal choices, decision quality has no further effect on moral judgments—a highly suboptimal choice is seen as no worse than a marginally suboptimal choice. These effects held up for judgments of wrongness and punishment (Experiment 1), positive and negative outcomes (Experiment 2), and agents with positive and negative intentions (Experiment 3). We argue that these results reflect a broader tendency to irresistibly apply the Efficiency Principle when explaining behavior

A core proposition in economics is that voluntary exchanges benefit both parties. We show that people often deny the mutually beneficial nature of exchange, instead using zero-sum thinking. Participants read about simple exchanges of goods and services, judging whether each party to the transaction was better off or worse off afterwards. These studies revealed that zero-sum beliefs are pervasive. These beliefs seem to arise in part due to intuitive mercantilist beliefs that money has value over- and-above what it can purchase, since buyers are seen as less likely to benefit than sellers, and barters are often seen as failing to benefit either party (Study 1). Zero-sum beliefs are greatly reduced by giving reasons for the exchange (Study 2), suggesting that a second mechanism underlying zero-sum thinking is a failure to spontaneously take the perspective of the buyer. Implications for politics and business are discussed.

Our ability to induce the general from the specific is a hallmark of human cognition. Inductive reasoning tasks ask participants to determine how strongly a set of premises (e.g., Collies have sesamoid bones) imply a conclusion (Dogs have sesamoid bones). Here, we present evidence for an abductive theory of inductive reasoning, according to which inductive strength is determined by treating the conclusion as an explanation of the premises, and evaluating the quality of that explanation. Two inductive reasoning studies found two signatures of explanatory reasoning, previously observed in other studies: (1) an evidential asymmetry between positive and negative evidence, with observations casting doubt on a hypothesis given more weight than observations in support; and (2) a latent scope effect, with ignorance about potential evidence counting against a hypothesis. These results suggest that inductive reasoning relies on the same hypothesis evaluation mechanisms as explanatory reasoning

Our beliefs guide our actions. But do potential actions also guide our beliefs? Three experiments tested whether people use pragmatist principles in fixing their beliefs, by examining situations in which the evidence is indeterminate between an innocuous and a dire explanation that necessitate different actions. According to classical decision theory, a person should favor a prudent course of action in such cases, but should nonetheless be agnostic in belief between the two explanations. Contradicting this position, participants believed the dire explanation to be more probable when the evidence was ambiguous. Further, when the evidence favored either an innocuous or a dire explanation, evidence favoring the dire explanation led to stronger beliefs compared to evidence favoring the innocuous explanation. These results challenge classic theories of the relationship between belief and action, suggesting that our system for belief fixation is sensitive to the utility of potential beliefs for taking subsequent action

According to probabilistic theories of higher cognition, beliefs come in degrees. Here, we test this idea by studying how people make predictions from uncertain beliefs. According to the degrees-of-belief theory, people should take account of both high- and low-probability beliefs when making predictions that depend on which of those beliefs are true. In contrast, according to the all-or-none theory, people only take account of the most likely belief, ignoring other potential beliefs. Experiments 1 and 2 tested these theories in explanatory reasoning, and found that people ignore all but the best explanation when making subsequent inferences. Experiment 3A extended these results to beliefs fixed only by prior probabilities, while Experiment 3B found that people can perform the probability calculations when the needed probabilities are explicitly given. Thus, people’s intuitive belief system appears to represent beliefs in a ‘digital’ (true or false) manner, rather than taking uncertainty into account

People assess others’ moral characters to predict what theywill do. Here, we study the computational mechanismsused to predict behavior from uncertain evidence aboutcharacter. Whereas previous work has found that peopleoften ignore hypotheses with low probabilities, we find thatpeople often account for the possibility of poor moralcharacter even when that possibility is relatively unlikely.There was no evidence that comparable inferences fromuncertain non-moralized traits integrate across multiplepossibilities. These results contribute to our understandingof moral judgment, probability reasoning, and theory ofmind.