Children’s exploration distinguishes necessary and merely possible outcomes.

Preschoolers often fail tasks that require that they select between a necessary and a merely possible outcome. Prior work has interpreted these failures as evidence that children hold a minimal representation of possibility or as reflecting performance factors. However, all previous paradigms have operationalized children's modal understanding as a discrete choice or outcome, making it difficult to distinguish between these accounts. We introduce a continuous measure of search behavior to assess how modal status regulates exploration. American 3- and 4-year-olds (48% female, 52% male) searched for an object dropped into one of two boxes after passing through a set of either transparent (yielding a single necessary location) or opaque tubes (yielding two possible locations). In Experiment 1, both age groups spent relatively less time searching the first location they approached and switched more often when the outcomes were merely possible than when the outcome was necessary. Experiment 2 replicated this pattern in a touchscreen version. Experiment 3 demonstrated the same effect while controlling for object tracking by equating inferential demands across conditions. Across experiments, children's search behavior was aligned with modal status, indicating that representations of necessity and possibility guide exploration before children reliably succeed on discrete choice modal reasoning tasks. These results suggest children's early sensitivity to modal concepts is expressed in their continuous search behavior, shaping real-time decision making. Our findings inform theories of modal reasoning in early childhood, suggesting that modal representations may be more readily expressed through graded patterns of exploration rather than discrete choices. (PsycInfo Database Record (c) 2026 APA, all rights reserved).