The predictive value of the cognitive scale of the Bayley Scales of Infant and Toddler Development-III

The measurement of cognitive development is of major importance within developmental psy-chology research. However, empirical findings from longitudinal studies using the Bayley Scales of Infant and Toddler Development-III (BSID-III) are scarce. Moreover, few studies have assessed the predictive relationship between the BSID-III and later IQ measurements using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III). The aims of the current study were to investigate (1) the predictive relationship within the first, second, and third year of life using the Cognitive Scale of the BSID-III, (2) the predictive relationship between the Cognitive Scale of the BSID-III and the WPPSI-III Verbal IQ, Performance IQ and Full Scale IQ scores in the fifth year of life, and (3) the relationship of habituation speed and novelty preference with BSID-III and WPPSI-III scores. Therefore, 110 children were tested with the BSID-III at the ages of 6, 9, 18, and 26 months, with a habituation and novelty preference task at 9 months, and with the WPPSI-III at 50 months. Structural equation modeling revealed that BSID-III at all ages predicted the chil-dren's IQ obtained using the WPPSI-III at 50 months. Furthermore, all BSID-III scores predicted subsequent BSID-III scores. These findings highlight the predictive value of the Cognitive Scale of the BSID-III. Habituation speed and novelty preference were not related to the BSID-III or WPPSI-III scores. Explanations for these findings, limitations, and ideas for future studies are discussed.