In a review of heredity v environment theories, the author concludes that no individual, regardless of potential, can approach the full development of his or her abilities without exposure to an enriched environment. (Editor/SJL)

Claims in "The Bell Curve" that Head Start and other early intervention programs are a failure and a waste of funds depend on a notion of cognitive ability reduced to IQ. They ignore other studies that demonstrate the success of such programs and that, consistent with Piagetian views, recognize the interrelationships of cognitive,…