A Special Edition on Child Development - March 1999

Work, Money, Time and Learning Development

Most children in Canada are physically, emotionally and socially healthy. However, a number of children are experiencing problems developing learning capacity. According to the National Longitudinal Survey of Children and Youth (NLSCY), a quarter of preschoolers in Canada have some delays in the development of vocabulary skills and at least 10 percent are at critically low levels. These children are at risk of experiencing serious problems when they enter school. They will be more likely to repeat grades, drop out of school and have difficulty finding work later in life.

While many factors are generally thought to affect the development of learning capacity, there is little agreement as to the dominant factors. Pierre Lefebvre and Philip Merrigan of the University of Quebec at Montreal, in a paper based on the 1994 NLSCY, postulate that family labour force activity and income are two dominant determinants of the vocabulary skills of preschoolers. Labour force activity generates income — a positive effect — but reduces the amount of time a mother has to spend with her child — presumed to be a negative effect.

Lefebvre and Merrigan chose, as their measure of learning capacity, the Peabody Picture Vocabulary Test (PPVT), a measure of receptive vocabulary — the ability to understand words that are spoken to one by others — available for 3,000 children aged four and five. This measure is widely used as a predictor of future academic achievement. Family labour force activity is proxied by a calculation of the weeks-worked-per-year by the mother. Economic resources are measured as total family income as well as income from welfare.

The authors conclude that the mothers' time spent working had very little effect on children's learning capacity. Preschoolers scored about the same on the PPVT whether or not their mothers worked more or less than 26 weeks in the previous year. In fact, children with mothers strongly attached to the labour market scored slightly above the national average and those with mothers less attached to the labour market scored slightly below.

Note : PPVT (The Peabody Picture Vocabulary Test) is a measure of receptive vocabulary and is used as a predictor of future academic achievement.

Mothers strongly committed to the labour market read as frequently to their children as mothers less attached to the labour market

The authors explain this unexpected result by noting that mothers strongly committed to the labour market read as frequently to their children as mothers who are less active in the labour market. It turns out — not surprisingly — reading to a preschooler has been found to greatly improve a child's PPVT score. Children whose parents read little or almost never to them, all other factors being equal, score 5.8 percent lower than children whose parents read to them several times per day, and 3.9 percent lower than children read to once per day. A further implication of this result is that mothers, who are time constrained due to work and family responsibilities, are spending less time on activities other than interacting with their children.

Maternal education is also important to preschool vocabulary skills. The authors found a strong positive correlation between a mother's level of education and her preschooler's vocabulary skills. In fact, the mother's education is a more important factor than earned family income. A consensus explanation for this important effect — an effect that has also been found in other studies — has not emerged. One theory is that mothers with higher education talk more frequently to their children in the very early years, resulting in a significant head start in vocabulary. Another theory is that higher education is an indication of higher innate capacities of the mother, which she passes on genetically to her child. The authors do not deal with this question in their paper.

The importance of income to preschoolers' vocabulary skills is not found to be strong in the Lefevbre and Merrigan paper. An increase in income in the order of $20,000 will barely increase PPVT scores by one percent. However, where a part or the whole of that income is derived from welfare, a preschooler's vocabulary score decreases by about 3.5 percent. The authors conclude that increasing income could have much stronger effects for the very poor (children with mothers on welfare) than for the working poor, for example, and note that the National Child Benefit directed its additional support to the working poor.

Several interpretations of the importance of welfare income are possible and these lead to different policy implications. More research using longitudinal data will be done on this issue by the Applied Research Branch.