Previous research has shown that people are able to use distributional information about the environment to make inferences. However, how people learn these probability distributions is less well understood, especially for those that are not normal or unimodal. In this paper we focus on how people learn probability distributions that are bimodal. We examined on how the distance between the two peaks of a bimodal distribution and the numbers of observations influence how participants learn each distribution, using two types of stimuli with different degrees of perceptual noise. Overall, participants were able to learn the various distributions quickly and accurately. However, their performance is moderated by stimuli type—whether participants were learning a distribution over numbers (low noise) or over sizes of circles (high noise). This work suggests that although people are able to quickly learn a variety of distributions, many factors may influence their performance.

In this paper we explore a cognitive modeling approach to aggregating individuals’ estimates of unknown quantities without natural bounds. We carried out two experiments that elicited individuals’ estimates of the population of US metropolitan areas, and domestic box office returns for movies. We found that the means of individuals’ responses correlate well with the true sizes, but participants systematically underestimated these values. We formulated a cognitive model that uses the true values of known items to correct for individuals’ biases, and demonstrated that this model can drastically improve predictive accuracy. Because our model quantitatively infers individual’s biases on the estimation tasks we were able to examine the distribution of individual biases, and found that there were substantial between-individual differences in the magnitude of the responses. This work demonstrates how individuals’ biases, whether over- or underestimation, can be corrected using a cognitive model together with known ground truths

When learning from others, rather than simply following the majority’s opinion, we need to accurately evaluate the quality of the information both the majority and the minority provide, and integrate that information with our own personal experience. This is especially true when the majority’s opinion is based on lower quality information, because they shared the same evidence rather than collecting evidence independently. Previous work demonstrated that adults are sensitive to the quality of the majority’s information, consistent with the predictions of a Bayesian rational model (Whalen, Griffiths, & Buchsbaum, in press). In two behavioural experiments, we investigated how preschoolers combine testimony from a majority that conflicts with a minority or with the child’s own personal evidence. Unlike adults, children over-relied on the majority when given only testimony. However, when also given their own conflicting evidence, children relied significantly less on the majority and over-relied on their own evidence. These findings help explain why children may follow the majority at times, but in others trust their own judgements.

Across multiple species of social mammals, a growing number of studies have found that individual sociality is associated with survival. In long-lived species, like primates, lifespan is one of the main components of fitness. We used 18 years of data from the Lomas Barbudal Monkey Project to quantify social integration in 11 capuchin (Cebus capucinus) groups and tested whether female survivorship was associated with females' tendencies to interact with three types of partners: (1) all group members, (2) adult females, and (3) adult males. We found strong evidence that females who engaged more with other females in affiliative interactions and foraged in close proximity experienced increased survivorship. We found some weak evidence that females might also benefit from engaging in more support in agonistic contexts with other females. These benefits were evident in models that account for the females' rank and group size. Female interactions with all group members also increased survival, but the estimates of the effects were more uncertain. In interactions with adult males, only females who provided more grooming to males survived longer. The results presented here suggest that social integration may result in survival-related benefits. Females might enjoy these benefits through exchanging grooming for other currencies, such as coalitionary support or tolerance.

We investigate how children balance the quality of informants’ knowledge with the number of endorsements when deciding which of two boxes contains the better option. When group numbers are equal, children choose boxes endorsed by informants with visual access over informants with hearsay (Experiment 1), but are at chance when group size conflicts with quality of knowledge (Experiments 2 and 3). This suggests that children tend to conform to a majority opinion, compared to adults (Experiment 4) and a normative computational model. These studies suggest that preschoolers consider the testimony of multiple informants and evaluate their knowledge sources, but may assume that informants are more individually informative than they are