Final answer:
The focus of William James's work is known as functionalism, which looks at how mental activities assist individuals in adapting to their environment.
Step-by-step explanation:
William James's focus on how mental activities help a person adapt to his or her environment is known as functionalism. Functionalism is a perspective in psychology that emphasizes the purpose or function of behavior and how it helps individuals fit into their environment. It is different from other perspectives like psychoanalysis, behaviorism, and structuralism. Functionalism was influenced by Darwin's theory of evolution and the idea that adaptations are important for survival and reproduction.