The University Record, March 29, 1993

Family income powerful predictor of 5-year-olds’ IQ, behavior

By Diane Swanbrow
News and Information Services

Poverty leaves measurable scars on 5-year-old children’s intelligence and behavior, according to a study presented last week at the meeting of the Society for Research in Child Development. And the longer children have lived in poverty, the deeper those scars are likely to be.

The study is the first to assess how much more common and persistent poverty is among Black children at both the family and the neighborhood levels.

Over the six-year period studied, three-quarters of the white children in the nationally representative panel study of nearly 7,200 families were never poor—defined by the U.S. Bureau of the Census as an annual income of $13,924 for a family of four. Fully one-half the white children escaped poverty at the neighborhood as well as the family level, reported economics Prof. Greg J. Duncan, researcher at the Institute for Social Research (ISR).

The situation for Black children is vastly different. Only one-third escaped family poverty altogether, and just 5 percent managed to escape poverty at both the neighborhood and family levels.

Collaborating with Duncan on the study were developmental psychologists Jeanne Brooks-Gunn of Columbia University and Pamela Kato Klebanov of the Educational Testing Service.

The study also showed that poverty was not only much more prevalent among Black children, but also more persistent, Duncan reported. Of ever-poor white children (one-quarter of the white children studied) only 20 percent were poor for at least five of the six years studied. Of ever-poor Black children (two-thirds of the Black children surveyed) fully 50 percent remained poor for at least five years.

Duncan and his colleagues also examined the links between economic deprivation and children’s development, using data from the Infant Health and Development Program, a separate sample of nearly 900 low-birthweight children followed from birth to age 5. They sorted the effects of income from the effects of family structure and other factors generally considered together as “socioeconomic status.”

“Family income is a far more powerful correlate of a child’s IQ at age 5 than maternal education, ethnicity and growing up in a single-parent family,” Duncan said. “And the effects of persistent poverty are roughly twice as large as the effects of transient poverty on children’s intelligence.

“The effects poverty has on children’s behavior were also significant,” he said. “Children whose families were poor the entire four years of the study were considerably more likely than those whose families were poor only part of that time to be fearful, anxious, unhappy, or depressed, or to destroy their own things or have temper tantrums.”

According to Duncan and his colleagues, these results suggest that the effects of poverty are cumulative—the longer people are exposed to poverty, the deeper the cognitive and behavioral wounds it inflicts.

In 1991, he pointed out, 21.8 percent of American children—some 14.3 million in all—lived in families in which total income failed to exceed even the Spartan thresholds used to define poverty by the U.S. Bureau of the Census.

“There is little doubt that children raised in poverty have less enjoyable childhoods,” Duncan said. “But in contrast with the apparent precision with which poor children are counted, the effects of economic deprivation on children are not yet well understood. The results of this study begin to delineate the extent to which poverty reduces a child’s chances for success and happiness in later life.”