Our last topic—the story of visual stimulation, genes, and brain cells—illustrates a theme that you saw throughout this chapter: Biological and environmental factors interact. Research on (1) people and the social contexts in which they live, and on (2) genes, neurons, and the whole organism in which they function, leads to the same conclusion: Biology and the environment—nature and nurture—are not competing forces, fighting for control over an organism. They are partners. They need each other. This is the major lesson of contemporary research on nature and nurture.

You will see this lesson again and again in other chapters of this book, for example, as we explore the ways in which nature and nurture combine to shape emotional experience and health (Chapter 6), thinking processes (Chapter 9), personality (Chapter 13), psychological development (Chapter 14), and the experience of psychological disorders (Chapters 15 and 16).

Chapter Review Now that you have completed this chapter, be sure to turn to Appendix B, where you will find a Chapter Summary that is useful for reviewing what you have learned about nature, nurture, and their interaction.