Historically, research on preschool-aged children’sprobabilistic reasoning abilities has yielded mixed results.Although some findings have suggested that young childrencan successfully evaluate probabilities, others have suggestedthat they may use strategies that only approximate trueprobabilistic inference and therefore sometimes make errors(e.g., Girotto et al., 2016; Piaget & Inhelder, 1975). To explorethe factors that affect young children’s probabilistic reasoning,we developed a battery of problems that contained features thataffect the ease with which a problem is evaluated, and the typesof alternative strategies that can be applied to solve them. Thecurrent experiments (total N = 124) assessed 3- and 4-year-oldchildren’s probabilistic reasoning using an experimentalparadigm tailored to this age group. Results from bothexperiments suggest that young children are able to engage intrue probabilistic inference, as they performed well-abovechance on each problem. Nuances in children’s performanceare discussed, along with possibilities for future research.

Adults tend to make biased inferences when they are givenbase-rates that conflict with individuating information (i.e., apersonality description). More recent work has shown thatchildren rely on individuating information by the age of 6,though 4-year-olds rely more on numerical information,arguably providing the more normative response (Gualtieri &Denison, 2018). In two experiments (N = 80 per experiment),we explored age differences in 4- and 6-year-old children’sability to integrate base-rate and individuating information bymanipulating the strength of the information provided. Four-year-olds’ responses reflected more base-rate use, regardless ofthe strength of the individuating information. Six-year-oldsweighed the information at hand, showing a general preferencefor the individuating information but relying more on the base-rates when the individuating information was less informative.Though younger preschoolers may overuse base-rateinformation, with development there is an increased sensitivitytoward individuating information and weighing information.

This paper examines the development of therepresentativeness heuristic in early childhood. Using a novelparadigm, we investigated 3- to 6-year-old children’s abilityto use base-rate and individuating information in theirpredictive inferences. In Experiment 1, we presented childrenwith base-rate and individuating information separately to testtheir ability to use each independently. In Experiment 2, wepresented children with base-rate and individuatinginformation together. Two critical trial types were used, onein which the base-rate information and individuatinginformation pointed to the same response and one in whichthe base-rate and individuating information pointed toconflicting responses. Results suggest that children progressto adult-like heuristic-based responding at 6 years of age.

Empirical evidence suggests infants can make inferences about uncertain future events using probabilistic data (Denison & Xu, 2010; Teglas et al., 2007). However, it is unclear if infants are using information about proportions to make these decisions. Infants were presented with population jars that contained large distributions of objects, and were tasked with deciding which of the two jars was more likely to yield a desirable object on a single draw. In Experiment 1, most infants chose the jar that contained only preferred objects over a jar that contained a 3:1 ratio of preferred objects. Most infants also made the correct choice when presented with the reverse ratios (choosing a 1:3 over a 0:1 ratio). In Experiment 2, infants correctly chose the jar that contained a 4:1 ratio of preferred objects over a jar that contained a 1.5:1 ratio. However, infants performed at chance when presented with the reverse ratios.