Preschoolers perform more informative experiments after observing theory-violating evidence.

This study investigated the effect of evidence conflicting with preschoolers' naive theory on the patterns of their free exploratory play. The domain of shadow size was used--a relatively complex, ecologically valid domain that allows for reliable assessment of children's knowledge. Results showed that all children who observed conflicting evidence performed an unconfounded informative experiment in the beginning of their play, compared with half of the children who observed confirming evidence. Mainly, these experiments were directed at investigating a dimension that was at the core of children's initial theory. Thus, preschoolers were flexible in the type of experiments they performed, but they were less flexible in the content of their investigations.