A first glimpse at healthy brain and behavioral d...( ty psychosocial function reading and ...),Health

Overall, this healthy group performed better than previously reported norms. However, analysis of the first wave of data also found that:

• Sex predicted few aspects of cognitive function, with gender effects less prevalent than in some previous studies. Boys performed better on perceptual analysis, and girls performed better on processing speed and motor dexterity. Girls also showed a slight advantage on verbal learning, but by adolescence, this advantage had disappeared.

• Income predicted IQ and academic achievement. Lower income was associated with lower IQ scores (mean IQs were 105, 110, and 115 for low-, middle- and high-income children respectively). Lower-income children were more likely to be excluded from the study because of medical or developmental conditions; the healthy low-income children who qualified performed, on average, better than previously reported population averages. "We were pleasantly surprised by how well the lower-income children did when we focused on those who were healthy," says Waber. Although income did not predict performance on basic cognitive tasks, such as memory or reading individual words, lower-income children did score lower on tests like reading comprehension and calculation. The authors suggest that such tasks, which require more reasoning and integration of cognitive abilities, are more vulnerable to the effects of poverty-related factors than are more basic skills.

• Age predicted performance on every measure of cognitive function. Performance climbed steeply from age 6, but leveled off overall for most tests between 10 and 12 years of age, then improved more slowly or not at all during adolescence. Waber cautions, however, that these data are "snapshots" at a single point in
  '"/>