Galton, a cousin of Charles Darwin, was heavily influenced by Darwin's theory of evolution. He believed that intelligence and other human traits were inherited and could be improved through selective breeding. To support this idea, he studied the biographies of successful people, assuming that their success was due to their inherited abilities.
Galton's work led to the development of the field of eugenics, which aimed to improve the human race through selective breeding. However, his theories were later discredited because they were based on faulty assumptions and were used to justify racist and discriminatory practices.