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Journal Issue: School Readiness: Closing Racial and Ethnic Gaps Volume 15 Number 1 Spring 2005

Genetic Differences and School Readiness
William T. Dickens

Social Multipliers and the Effect of Averaging

If most external environmental influences are transitory and transitory environmental effects are unable to drive multipliers, what explains the large gains in cognitive ability over the past century? That question has two answers. One is the social multiplier process. The other is that many random transient environmental effects that lean in one direction when averaged together can substitute for a single persistent environmental cause. This is the third point missed by the argument that claims that high heritability implies small environmental effects.

Another basketball analogy will help explain social multipliers. During the 1950s television entered many U.S. homes. Professional basketball, with its small arena, could not reach as wide an audience as baseball, but basketball translated much better to the small screen. Thus public interest in basketball began to grow. The increased interest made it easier for enthusiasts to find others to play with, thus increasing the opportunities to improve skills. As skills improved, standards of play rose, with players learning moves and skills from each other. As more people played and watched the game, interest increased still further. More resources were devoted to coaching basketball and developing basketball programs, providing yet more opportunities for players to improve their skills. In the end, the small impetus provided by the introduction of television had a huge impact on basketball skills.

A similar process may well be at work for cognitive ability. An outpouring of studies in recent years suggests that social effects have an important influence on school performance.30 One study of an experimental reduction in school class size resulting in major achievement score gains suggests that a very large fraction of the gains came through the children's extended association with their peers, who shared the experience of small class sizes.31 In this case an arguably minor intervention had large and long-lasting effects largely owing to a social multiplier effect.

But improvements in cognitive ability could have many triggers, rather than a single one. Many such triggers over the past half-century averaged together could be acting to raise cognitive ability. Increasing cognitive demands from more professional, technical, and managerial jobs; increased leisure time; changing cognitive demands of personal interactions; or changing attitudes toward intellectual activity could all be playing a role. And small initial changes along any of these dimensions would be magnified by individual and social multipliers.