Some psychologists focus their study on how humans and other animals learn and how some experiences can lead to changes in behavior and mental processes. Because the process of learning requires both physiological and psychological processes to work together, the two preceding units provide the foundation for this unit. Many psychologists who study learning focus on observable behaviors and how those behaviors can be changed or reinforced. Other learning psychologists study how the individual’s observations of other peoples’ behaviors influence changes in that individual’s mental processes and resulting behaviors.