In the context of the psychology of emotion, William James and John Dewey would be most interested in:

The correct answer is: William James and John Dewey would be most interested in how behavior aids one's adaptation to the environment.

Both William James and John Dewey, are phycologists associated with what is known as Functionalism. This method is heavily influenced by Darwin's ideas about adaptation to the environment. Over time we have been able to observe significant changes in the physical and behavioral aspects of human beings. These changes in behavior and in life style show us the capacity of adaptation of humans. Humans frequently adapt to the place they live in, this means that their body parts, the functions these body parts perform, as well as their behavior give human more survival and reproductive possibilities. If Darwin was correct, there is variation or differences in adaptation resulting in natural selection.

Behavior can change, also, due to psychological states such as beliefs or values. Universal structures in behavior are adjusted by experience and culture. The biological characteristics of men have changed from the ones of primitive men, which dedicated their life to hunting and fishing. Now days we have other priorities and we behave according to them, or to satisfy them.