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Significance Correct probabilistic evaluations are one of the hallmarks of rationality. Is the human ability to make them dependent on formal education, or does it emerge regardless of instruction and culture? This paper shows that preliterate and prenumerate Mayan adults are able to solve a variety of probabilistic problems. These individuals correctly use prior and posterior information, proportions and elementary combinatorial procedures to predict the occurrence of random outcomes. And they perform like Mayan school children and Western controls. The finding that adults with no formal education are able to make suitable predictions indicates that, regardless of schooling and culture, the human mind possesses a basic probabilistic knowledge. Is there a sense of chance shared by all individuals, regardless of their schooling or culture? To test whether the ability to make correct probabilistic evaluations depends on educational and cultural guidance, we investigated probabilistic cognition in preliterate and prenumerate Kaqchikel and K’iche’, two indigenous Mayan groups, living in remote areas of Guatemala. Although the tested individuals had no formal education, they performed correctly in tasks in which they had to consider prior and posterior information, proportions and combinations of possibilities. Their performance was indistinguishable from that of Mayan school children and Western controls. Our results provide evidence for the universal nature of probabilistic cognition.

Many organisms can predict future events from the statistics of past experience, but humans also excel at making predictions by pure reasoning: integrating multiple sources of information, guided by abstract knowledge, to form rational expectations about novel situations, never directly experienced. Here, we show that this reasoning is surprisingly rich, powerful, and coherent even in preverbal infants. When 12-month-old infants view complex displays of multiple moving objects, they form time-varying expectations about future events that are a systematic and rational function of several stimulus variables. Infants' looking times are consistent with a Bayesian ideal observer embodying abstract principles of object motion. The model explains infants' statistical expectations and classic qualitative findings about object cognition in younger babies, not originally viewed as probabilistic inferences.

Rational agents should integrate probabilities in their predictions about uncertain future events. However, whether humans can do this, and if so, how this ability originates, are controversial issues. Here, we show that 12-month-olds have rational expectations about the future based on estimations of event possibilities, without the need of sampling past experiences. We also show that such natural expectations influence preschoolers' reaction times, while frequencies modify motor responses, but not overt judgments, only after 4 years of age. Our results suggest that at the onset of human decision processes the mind contains an intuition of elementary probability that cannot be reduced to the encountered frequency of events or elementary heuristics.

We introduce the Conceal or Reveal Dilemma, in which individuals receive unfair benefits, and must decide whether to conceal or to reveal this unfair advantage. This dilemma has two important characteristics: it does not lend itself easily to cost-benefit analysis, neither to the application of any strong universal norm. As a consequence, it is ideally suited to the study of interindividual and intercultural variations in moral-economic norms. In this paper we focus on interindividual variations, and we report four studies showing that individuals cannot be swayed by financial incentives to conceal or to reveal, and follow instead fixed, idiosyncratic strategies. We discuss how this result can be extended to individual and cultural variations in the tendency to display or to hide unfair rewards.

Disagreement on the “probability status” of chances casts doubt on Girotto and Gonzalez’s ( 2001 ) conclusion that the human mind can make sound Bayesian inferences involving single-event probabilities. The main objection raised has been that chances are de facto natural frequencies disguised as probabilities. In the present study, we empirically demonstrated that numbers of chances are perceived as being distinct from natural frequencies and that they have a facilitatory effect on Bayesian inference tasks that is completely independent from their (minor) frequentist readings. Overall, therefore, our results strongly disconfirm the hypothesis that natural frequencies are a privileged cognitive representational format for Bayesian inferences and suggest that a significant portion of laypeople adequately handle genuine single-event probability problems once these are rendered computationally more accessible by using numbers of chances.

Do moral appraisals shape judgments of intentionality? A traditional view is that individuals first evaluate whether an action has been carried out intentionally. Then they use this evaluation as input for their moral judgments. Recent studies, however, have shown that individuals’ moral appraisals can also influence their intentionality attributions. They attribute intentionality to the negative side effect of a given action, but not to the positive side effect of the same action. In three experiments, we show that this asymmetry is a robust effect that critically depends on the agent’s beliefs. The asymmetry is reduced when agents are described as not knowing that their action can bring about side effects, and is eliminated when they are deemed to hold a false belief about the consequences of their actions. These results suggest that both evaluative and epistemic considerations are used in intentionality attribution.

This commentary questions Elqayam & Evans' (E&E's) claims that thinking tasks are doomed to have multiple normative readings and that only applied research allows normative evaluations. In fact, some tasks have just one undisputed normative reading, and not only pathological gamblers but also normal individuals sometimes need normative guidance. To conclude, normative evaluations are inevitable in the investigation of human thinking.

Why do individuals mentally modify reality (e.g., “If it hadn’t rained, we would have won the game”)? According to the dominant view, counterfactuals primarily serve to prepare future performance. In fact, individuals who have just failed a task tend to modify the uncontrollable features of their attempt (e.g., “If the rules of the game were different, I would have won it”), generating counterfactuals that are unlikely to play any preparatory role. By contrast, they generate prefactuals that focus on the controllable features of their ensuing behavior (e.g., “If I concentrate more, I will win the next game”). Here, we test whether this tendency is robust and general. Studies 1a and 1b replicate this tendency and show that it occurs regardless of whether individuals think about their failures or their successes. Study 2 shows that individuals generate relatively few controllable counterfactuals, unless explicitly prompted to do so. These results raise some questions regarding the generality of the dominant view according to which counterfactuals mainly serve a preparatory function.

How do individuals think counterfactually about the outcomes of their decisions? Most previous studies have investigated how readers think about fictional stories, rather than how actors think about events they have actually experienced. We assumed that differences in individuals' roles (actor vs. reader) can make different information available, which in turn can effect counterfactual thinking. Hence, we predicted an effect of role on postdecisional counterfactual thinking. Reporting the results of eight studies, we show that readers undo the negative outcome of a story by undoing the protagonist's choice to tackle a given problem, rather than the protagonist's unsuccessful attempt to solve it. But actors who make the same choice and experience the same negative outcome as the protagonist undo this outcome by altering features of the problem. We also show that this effect does not depend on motivational factors. These results contradict current accounts of counterfactual thinking and demonstrate the necessity of investigating the counterfactual thoughts of individuals in varied roles.