By Jessica Rogers, published on November 1, 2000 - last reviewed on July 13, 2009
Age and wisdom don't always go hand in hand--despite your eldest siblings' claims.
Challenging popular belief is new research, published in American Psychologist, that asserts that there is no direct link between birth order and intelligence, and that concerns that big families produce less intelligent children are misguided. According to Joseph Lee Rodgers, Ph.D., a University of Oklahoma psychology professor, prior related studies were fundamentally flawed, as they did not compare children within families. Therefore, he evaluated data from within families using the 1979 National Longitudinal Survey of Youth, a consolidation of IQ test scores taken biannually from a group of children aged 14 to 21.
Rodgers found that today's large U.S. families don't necessarily produce low-IQ children. Instead, he suggests that more educated parents with set career paths are more likely to have fewer children because they tend to postpone childrearing.