The development of children in a Swedish urban community. A prospective longitudinal study. IV. Data on the mental development during the first five years.

Abstract

SummaryThe psychomotor (up to 2 years) and mental development of around 200 children as reflected in the Brunet‐Lézine and Terman‐Merrill tests has been followed from 3 months to 5 years in a longitudinal study.The gestational age of the child is found to he related to developmental level during the 9 first months.Pearsson correlations have been calculated. The correlations between proximate ages are of the order of 0.50–0.75 but diminish quickly with increasing time intervals. Like most other authors we have found that tests for infants have little long‐term predictive value for normal children, but that predictability increases with age.Significant differences between the sexes in favour of girls are present from 18 months to 3 years, most marked at 2 years. Girls are more advanced particularly in the language and social sphere. This difference is not equally distributed over all social classes, a significant difference between the sexes being found principally within the lowest class. There is a tendency in the same direction within the highest class, while no significant differences exist within the middle class.Significant differences in developmental level were found between social classes. Two types of classification were applied, the Swedish and Graffar's system.At 3 and 6 months the mean quotients of the highest social class are low compared with the middle and lowest classes; with the Swedish system of social grouping the differences are significant. At 9 and 12 months the classes do not differ significantly. From 18 months there are significant differences in the opposite direction, the highest class having the higher and the lowest the lower mean quotients. At 3 and 5 years the difference is significant at the 0.001 level on the basis both of Swedish and of Graffar's classification.The socio‐economic special scales (occupation, mother's education, housing, income) were related to developmental level up to 5 years of age. A positive relation is earliest manifested in respect of the mother's educational level and the family's occupational status (from 18 months). At 3 and 5 years the children with better conditions in all four scales have significantly higher quotients.From 3 months to 2 years the motor, coordination, language and social mean quotients in the development test were related to socio‐economic total and partial scales. There are no significant differences in any of the quotients for children living in better than in worse housing conditions.The group of children whose parents have low incomes compared with those of parents with high incomes are significantly forward in, particularly, coordination ability at 3 and 6 months, and in respect of social and motor development at 3 months.Children of parents in the high occupational group have significantly higher coordination quotients at 18 and 24 months than have children of parents in the low group. In other respects there is no significant relation between subscale quotients and occupational grouping.As regards the mother's educational level, there is an almost significant relation with the child's language development from 12 months of age in favour of the more highly educated group. This significance level is successively strengthened at 18 and 24 months. A highly significant relation between mother's educational level and child's coordination ability exists also at 18 and 24 months.The child's development level was related to maternal age. At 2 years the mean quotients of the children of young mothers (25 years) are significantly higher than those of older mothers' children (> 32 years). At 3 and 5 years the children of medium‐aged mothers (26–32 years) have significantly higher quotients than those of young and older mothers.First‐born are more developed than second‐born during the first 2 years, the differences between the mean quotients of the first‐born and second‐born being significant at 6, 9 and 24 months. At 2 years the difference is most marked in the language sphere.No significant differences in mean quotients between legitimate and illegitimate children exist until 5 years of age, when the difference is clearly significant in favour of the legitimate ones. Children conceived before marriage were compared with those conceived after marriage, the former being significantly more developed at 6 months. As from 18 months the tendency is reversed and at 5 years the difference is clearly significant in favour of children conceived after marriage.The child's development level was related to the gainful employment of mothers from 1 to 5 years. No significant differences were found at any age between the mean quotients of the children of gainfully employed mothers and others.Possible interactions between various social and family factors are discussed.