FIELDS OF BASIC PSYCHOLOGY
Perhaps the oldest and longest thread in the growth of psychology as a research discipline
ties psychology to biological study.
Physiological and comparative psychology grew primarily from the evolutionary theories of Charles Darwin. Learning was added as a basic component of psychology near the beginning of the 20th century. These three fields are discussed below.
Physiological Psychology
Applying neuroanatomy and neurophysiology to the study of behavior, physiological psychology asks such questions as: Which structures of the brain and nerves grow and change in animal and human action? What are the neural networks that manage sensory experience? Physiological
psychologists have become especially interested in hormonal and biochemical changes in nerves, glands, and musclesÑchanges that may be closely related to human development, emotion, and learning. Much additional research is necessary before explicit links can be made (if ever) between DNA and learning French, for example, but physiological psychologists are moving steadily toward a resolution of the ancient question of how the brain relates to behavior. One such area of research is described in the article on brain bilateralism.
Comparative Psychology
Comparative psychology investigates animal behavior. More modest about the lessons of animals for human beings than their 19th-century forerunners, comparative psychologists continue to be interested in animal behavior in its own right and as a potential model for understanding human behavior. Ethology, a subgroup of comparative psychology, studies animals ranging from ducks and rats to baboons, in natural settings, and tries to draw general conclusions about patterns of mating, parental care, and adaptation.
Learning
The study of learning is one of the central themes of psychology, with connections to child psychology, physiological psychology, education, and therapy. Learning psychologists examine simple behavior in animalsÑfor example, pigeons learning which of several keys to peck for a reward. Learning psychologists also study human learning, design procedures and devices for educational application (such as teaching machines), and develop programs for modifying problem behavior. In the history of psychology learning psychologistsÑespecially Ivan Pavlov, John B. Watson, Clark Hull, and B. F. SkinnerÑhave uniformly represented psychology as a science, subject to the same rules of evidence and inference that characterize physics or biology. They have also usually argued for simple and straightforward explanations of behavior and for the efficacy of reward and punishment in the modification of behavior. The articles behaviorism and behavior modification outline key principles.