The phrase in its modern sense was popularized by the English Victorian polymath Francis Galton , the modern founder of eugenics and behavioral genetics , discussing the influence of heredity and environment on social advancement.    Galton was influenced by the book On the Origin of Species written by his half-cousin, Charles Darwin .
Even today, different branches of psychology often take a one versus the other approach. For example, biological psychology tends to stress the importance of genetics and biological influences. Behaviorism, on the other hand, focuses on the impact that the environment has on behavior.