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School Psychology Quarterly





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Academic achievement, Compensatory education, Early childhood, Head Start, Intelligence, Meta-analysis, Preschool, Review


Some scholars who emphasize the heritability of intelligence have suggested that compensatory preschool programs, designed to ameliorate the plight of socioeconomically or otherwise environmentally impoverished children, are wasteful. They have hypothesized that cognitive abilities result primarily from genetic causes and that such environmental manipulations are ineffective. Alternatively, based on the theory that intelligence and related complex human behaviors are probably always determined by myriad complex interactions of genes and environments, the present meta-analytic study is based on the assumption that such behaviors can be both highly heritable and highly malleable. Integrating results across 35 preschool experiments and quasi-experiments, the primary findings were: (a) preschool effects on standardized measures of intelligence and academic achievement were statistically significant, positive, and large; (b) cognitive effects of relatively intense educational interventions were significant and very large, even after 5 to 10 years, and 7 to 8 of every 10 preschool children did better than the average child in a control or comparison group; and (c) cumulative incidences of an array of personal and social problems were statistically significantly and substantially lower over a 10- to 25- year period for those who had attended preschool (e.g., school drop out, welfare dependence, unemployment, poverty, criminal behavior). The need for a very large, well-controlled, national experiment to either confirm or refute these provocative, review-generated findings is discussed.