Genetics and Behavior

Why do people differ from one another in temperament, ability, and vulnerability to mental illness? The biological approach proposes that part of the answer lies in our genes. This lesson examines how psychologists investigate the genetic basis of behavior, what heritability really means, and why the most compelling modern research emphasizes the interaction between genes and environment rather than genes alone.

Genes are segments of DNA that provide instructions for building proteins, and they are inherited from our parents. The genotype is an individual's complete genetic makeup, while the phenotype is the observable set of characteristics that results from the interaction of genotype with environment. A central question in psychology is how much of the variation in a given behavioral tr