The Evolution of Everything: How New Ideas Emerge

by Matt Ridley

Still more surprising to many people is that in conditions of greater economic equality, IQ becomes more heritable, not less. In a world of more ample and more equally distributed food, obesity becomes more heritable, not less. This is because where many go hungry, fortune will largely determine who gets fat. Once everybody has enough food, the ones who get fat will be the ones with a genetic tendency to do so, and fatness will appear to run more in families – to be more heritable. The same with intelligence. Once everybody gets a similarly good education, the high achievers will increasingly be found among the children of high achievers, rather than the children of those with the best resources. It follows that a high correlation between the achievements of parents and their children, far from indicating that the parents are giving their children unfair environmental advantages, indicates instead that opportunity is being gradually levelled.