Participants can adequately take into account several cues regarding the weight they should grant majority opinions,but that they do not consistently take into account cues regarding whether the members of the majority have formed theiropinions independently of each other. We suggest that these conflicting results can be explained by hypothesizing that somecues are evolutionarily valid (i.e. they were present and reliable during human evolution), and others not. Using this frameworkwe derive and test hypotheses about two facets of informational dependency. The first 3 experiments show that participantsadequately take into account cues to informational dependency when they are presented in a simple, evolutionarily valid way.Experiments 4 to 7 show that people consistently take into account shared motivation, but not shared cognitive traits, as a sourceof potential dependency, as predicted by the likely greater importance of differences in motivation during our evolutionaryhistory.

Are people who agree on something more likely to be right and competent? Evidence suggests that people tend to make this inference. However, standard wisdom of crowds approaches only provide limited normative grounds. Using simulations, we argue that when individuals make independent and unbiased estimates, under a wide range of parameters, individuals whose answers converge with each other tend to have more accurate answers and to be more competent. In 2 experiments (UK participants, total N = 399), we show that participants infer that informants who agree have more accurate answers and are more competent, even when they have no priors, and that these inferences are weakened when the informants are systematically biased. In conclusion, we speculate that inferences from convergence to accuracy and competence might help explain why people deem scientists competent, even if they have little understanding of science.