Comparisons of Mental and Motor Test Scores for Ages 1-15 Months by Sex, Birth Order, Race, Geographical Location, and Education of Parents

the study population is found to be representative of the United States., Comparisons of means and standard deviations of total scores for each of the 15 months were made for a series of subsamples of the population. No differences in scores were found for either scale between boys and girls, first-born and later-born, education of either father or mother, or geographic residence. No differences were found between Negroes and whites on the Mental Scale, but the Negro babies tended consistently to score above the whites on the Motor Scale. Scores for a small sample of Puerto Rican babies were the same as for the total white sample. In a discussion of the interpretation of these findings, emphasis was placed on the need to study in careful detail the development of mental processes in the second year of life. Within this period evidently will be found the explanation of the socioeconomic and ethnic differences in mental functioning that are repeatedly found for children of 4 years and older.