Children experience good and bad days in their performance. Although this phenomenon is well-known to teachers, parents, and students it has not been investigated empirically. We examined whether children's working memory performance varies systematically from day to day and to which extent fluctuations at faster timescales (i.e., occasions,…

In 2 studies, subjects between 7 and 16 years of age indicated predictions for the water level in a tilted container or the position of a plumb line. Found that sex differences were evident at all ages; task performance improved with age according to a discrete stage process; and task performance was determined by field effects and rule strategy.…

In this study an attempt was made to obtain a developmental dimension for estimating longitudinal development on the basis of cross-sectional data. To check the validity of this approach, the cross-sectional data were compared with true longitudinal data. Forty-three public school children were given a series of conservation tasks in four…