Hauser, Robert, and Alberto Palloni
Working paper no. 2010-05
Numerous studies find a positive relationship between cognitive ability, IQ as measured in childhood or youth, and subsequent survival. Explanations range from the idea that low ability is an indicator of adverse systemic events in early life to the idea that high cognitive functioning is required continuously to maintain health and reduce threats to survival. The Wisconsin Longitudinal Study (WLS) has followed a cohort of 10,317 Wisconsin high school seniors from 1957 onward. As expected, in the WLS adolescent cognitive ability (IQ) is positively correlated with survival from ages 18 to 69. However, rank in high school class accounts completely for the relationship between IQ and survival, and it has a much larger effect on survival. This finding could be interpreted as suggesting that cognitive functioning improves survival by promoting behaviors that boost health status, minimize exposure to known risks and, more generally, optimize returns to health producing inputs, and that such behaviors are firmly in place by late adolescence. Future research should identify those behaviors, their antecedents, and their consequences.