Cumulative Record. Chapter 32: Why Are the Behavioral Sciences Not More Effective. Quote 8

In hundreds of laboratories throughout the world, complex environments are arranged and their effects studied. The evidence grows more and more convincing that a person behaves as he does because of (1) what has happened in the distant past as his species evolved, and (2) what has happened to him in his lifetime as an individual. Practical solutions of some important problems then follow. (pp. 469-470)