An evaluation of the Northwestern Infant Intelligence Test, Test B

This study was designed to investigate the reliability, validity, and certain other features of the Northwestern Infant Intelligence Test, Test B. One hundred adoptive or boarding home babies between the ages of 13 and 36 weeks were tested with the Cattell Infant Intelligence Test. Three days later the Northwestern was administered. The Cattell was readministered to 64 of the 100 babies when they were 18 months of age. Findings show the following: (1) The IQs obtained on the Northwestern and Cattell were not directly comparable due to unequal means and standard deviations. (2) The Northwestern has a low ceiling at the upper age levels which prevents full expression of an infant's developmental skills between the ages of 30 and 36 weeks. (3) Odd-even reliability for the Northwestern and Cattell is similar for the 13 to 36 week age period but the reliability for the Northwestern is somewhat better than the Cattell at the 13-16 week period. The reliability of both tests improved with increasing age. (4) There appears to be a common factor in both tests at the 13 to 36 week period. This is especially true at the 13-21 week level--probably due to a preponderance of sensorimotor items on both tests for this age. 5. There was no significant sex difference found on the Northwestern. 6. The validity results indicate that prediction of a child's intelligence level at 18 months is a very risky procedure when based on performance on the Northwestern and Cattell at the 13-36 week period.