Three-year-old children's reasoning about possibilities.

Recent studies in cognitive development suggest that preschoolers may not be able to represent alternative possibilities, and therefore may lack modal concepts such as possible, impossible, and necessary (Leahy & Carey, 2020). We present two experiments adapted from previous probability studies but have a similar logical structure as those used in the previous modal reasoning tasks (Leahy, 2023; Leahy, Huemer, Steele, Alderete, & Carey, 2022; Mody & Carey, 2016). Three-year-old children have to choose between a gumball machine that must produce the desired gumball color and a gumball machine that merely might produce the desired gumball color.

Minimal representations of possibility at age 3.

Young children do not always consider alternative possibilities when planning. Suppose a prize is hidden in a single occluded container and another prize is hidden in an occluded pair. If given a chance to choose one container and receive its contents, choosing the singleton maximizes expected reward because each member of the pair might be empty.