After reading this chapter, you should be able to:

• Outline Darwin’s theory of natural selection and the historical context in which he developed it.
• Identify and evaluate the contributions Francis Galton made to the development of  psychology as an empirical science.
• Explain the importance of psychophysics as a foundation for experimental psychology.
• Discuss the work of the early experimental psychologists Hermann von Helmholtz, Christine Ladd-Franklin, and Hermann Ebbinghaus.