There are seven major sets of differences between young children of different economic backgrounds. The middle class child, compared to the lower class child, generally exhibits: (1) better language comprehension and expression, (2) richer schema development, involving mental preparation for the unusual, (3) stronger attachment to the mother, making him more receptive to adoption of her values and prohibitions, (4) less impulsive action, (5) a better sense of his potential effectiveness, (6) more motivation for school defined tasks, and (7) greater exceptation of success at intellectual problems. Data from two studies are offered in support of some of these hypotheses. One, a longitudinal study of 140 white, middle and lower class involved observations of their reactions at 4, 8, 13, and 27 months of age to masks with scrambled facial features. The other, a cross sectional study of 60 white, 10-month-old middle and lower class infants involved home observations of mother and child behaviors and laboratory observations of children's reactions to meaningful and non-meaningful speech, and to mothers' and strangers' voices. To bring about improved developmental patterns, it is important that lower class mothers be shown how they can become effective change agents in their children's lives. (NH)