Children's Representations of Possibility: Uncertainty About "What" Is Easier Than Uncertainty About "Where".

Young children struggle in situations involving mere possibility, such as when a target object could be in one of two possible locations. This difficulty is often interpreted as a general limitation on children's ability to reason about possibility. We tested the hypothesis that a source of children's difficulty may be their early-emerging object representational architecture, which necessarily represents where an object is, but only optionally represents what an object is. Two- to 4-year-old US children (n = 138) were tasked with finding a target object in one of several possible containers, and we manipulated whether the location or the identity of the target was uncertain. At all ages, children were better able to find the target when there was uncertainty about "what" versus uncertainty about "where". We suggest that children's object representational architecture can support uncertainty about identity but not location, and discuss implications for the development of possibility reasoning.