In this study the authors investigated whether children demonstrated the "underconfidence-with-practice" (UWP) effect. This effect is a highly robust metacognitive illusion in which adults become underconfident in their memory performance when asked to predict their memory for the same items across multiple study-test trials. One…

Data collection can be the most time- and cost-intensive part of developmental research. This article describes some long-proposed but little-used research designs that have the potential to maximize data quality (reliability and validity) while minimizing research cost. In "planned missing data designs", missing data are used…