Article: The association between intelligence and lifespan is mostly genetic

Background: Several studies in the new field of cognitive epidemiology have shown that higher intelligence predicts longer lifespan. This positive correlation might arise from socioeconomic status influencing both intelligence and health; intelligence leading to better health behaviours; and/or some shared genetic factors influencing both intelligence and health. Distinguishing among these hypotheses is crucial for medicine and public health, but can only be accomplished by studying a genetically informative sample.

A long standing, and powerful, assumption among many people is that human beings are born as a "blank slate" and that any differences in outcomes among individuals or various socioeconomic groups must be due to disadvantages and oppression. This is another nail in the coffin of that pernicious paradigm.

Key Messages

• It has been reported that brighter people live longer; we asked ‘why?'.
• We found, using data from three studies, that the small association between being brighter and living longer was mostly genetic in origin.
• This is a key finding in cognitive epidemiology; it is a further indication that intelligence is not just ‘school-smarts'.

I like this also because it shows the scientific method in operation.

Observation: Brighter people live longer.
Problem: Why do brighter people live longer?
Hypotheses: This positive correlation might arise from
1. socioeconomic status influencing both intelligence and health;
2. intelligence leading to better health behaviours;
3. and/or some shared genetic factors influencing both intelligence and health.
Experiment: retrospective analysis of three, long-term twin studies
Results: a small association between intelligence and living longer is mostly genetic in origin.
Conclusion: "intelligence is not just ‘school-smarts'."

Hypothesis falsification:
Factoring in socioeconomic factors, and health behaviors, using data from Sweden, seems to indicate that these factors do not influence lifespan.

In other word, environmental factors have a smaller effect on life span than genetic factors, such as intelligence.