Proceedings of the Annual Meeting of the Cognitive Science Society

What underlies young children’s failure in evaluating underinformative teachers? We explore the hypothesis that children have difficulty representing relevant alternatives; knowing what the teacher could have done. Children rated two teachers who demonstrated toys to a na¨ıve learner. One group first observed a fully informative teacher and then an underinformative teacher, while the other group saw the reverse order. Six- and seven-year-olds successfully rated the underinformative teacher lower than the fully-informative teacher regardless of the order (Exp.1). However, four- and five-yearolds showed this pattern only when they saw the fully informative teacher first (Exp.2). Given a binary choice after seeing both teachers, four-year-olds showed a preference for the fully informative teacher (Exp.3). We discuss these results in light of recent literature on children’s understanding of pragmatic violations in linguistic communication; the contrast between the fully informative vs. under-informative teachers might help children understand what the teacher could have shown.