Children’s understanding of conditional probabilities

From the weather forecast to the traffic report, consideration of conditional probabilities plays a central role in our everyday lives. Yet much of the research on children's understanding of probabilities has focused only on children's ability to anticipate simple, single-cause outcomes in the immediate future. Here, we introduced a new paradigm for assessing children's ability to reason about conditional probabilities. Specifically, we investigated 6- to 9-year-old children's ability to take multiple, contingent steps into account when considering the probability of a marble passing through a series of branching tubes. Although children across ages performed above chance overall, correlational analyses revealed that many children seemed to rely on heuristics rather than engaging in conditional probabilistic reasoning. Individual-level categorizations of response patterns also indicated striking variability in children's strategies. With its minimal verbal demands and intuitive stimuli, our task opens up important new avenues for clarifying how humans across ages approach probabilistic tasks.