Journal of Child and Adolescent Behavior
Open Access

Psychology is the science of mind and behavior. Psychology includes the study of conscious and unconscious phenomena, as well as feelings and thought. It is an academic discipline of immense scope. Psychologists also seek an understanding of the emergent properties of brains, linking the discipline to neuroscience. As a social science, psychologists aim to understand the behavior of individuals and groups.

A professional practitioner or researcher involved in the discipline is called a psychologist. Some psychologists can be classified as social, behavioral, or cognitive scientists. Some psychologists attempt to understand the role of mental functions in individual and social behavior. Others explore the physiological and biological processes that underlie cognitive functions and behaviors.

Psychologists explore behavior and mental processes, including perception, cognition, attention, emotion, intelligence, subjective experiences, motivation, brain functioning, and personality. Psychologists' interests extend to interpersonal relationships, psychological resilience, family resilience, and other areas within social psychology. Psychologists also consider the unconscious mind. Research psychologists employ empirical methods to infer causal and correlational relationships between psychosocial variables. Some, but not all, clinical and counseling psychologists rely on symbolic interpretation.

Psychologists in the United States campaigned for legislative changes to enable specially trained psychologists to prescribe psychotropic medications. Legislation in Idaho, Iowa, Louisiana, New Mexico, and Illinois has granted those who complete an additional master's degree program in psychopharmacology permission to prescribe medications for mental and emotional disorders. As of 2019, Louisiana is the only state where the licensing and regulation of the practice of psychology by medical psychologists (MPs) is regulated by a medical board (the Louisiana State Board of Medical Examiners) rather than a board of psychologists. While other states have pursued prescriptive privileges, they have not succeeded. Similar legislation in the states of Hawaii and Oregon passed through their respective legislative bodies, but in each case the legislation was vetoed by the state's governor.

While psychological knowledge is often applied to the assessment and treatment of mental health problems, it is also directed towards understanding and solving problems in several spheres of human activity. By many accounts, psychology ultimately aims to benefit society. Many psychologists are involved in some kind of therapeutic role, practicing in clinical, counseling, or school settings. Other psychologists conduct scientific research on a wide range of topics related to mental processes and behavior. Typically, the latter group of psychologists works in academic settings (e.g., universities, medical schools, hospitals). Another group of psychologists is employed in industrial and organizational settings. Yet others are involved in work on human development, aging, sports, health, forensics, and the media.

The German psychologist Hermann Ebbinghaus, a researcher at the University of Berlin, was another 19^th-century contributor to the field. He pioneered the experimental study of memory and developed quantitative models of learning and forgetting. In the early twentieth century, Wolfgang Kohler, Max Wertheimer, and Kurt Koffka co-founded the school of Gestalt psychology (not to be confused with the Gestalt therapy of Fritz Perls). The approach of Gestalt psychology is based upon the idea that individuals experience things as unified wholes. Rather than reducing thoughts and behavior into smaller component elements, as in structuralism, the Gestaltists maintained that whole of experience is important, and differs from the sum of its parts.

Psychologists in Germany, Denmark, Austria, England, and the United States soon followed Wundt in setting up laboratories. G. Stanley Hall, an American who studied with Wundt, founded a psychology lab that became internationally influential. The lab was located at Johns Hopkins University. Hall, in turn, trained Yujiro Motora who brought experimental psychology, emphasizing psychophysics, to the Imperial University of Tokyo.

Another student of Wundt, the Englishman Edward Titchener, created the psychology program at Cornell University and advanced "structuralist" psychology. The idea behind structuralism was to analyze and classify different aspects of the mind, primarily through the method of introspection. William James, John Dewey, and Harvey Carr advanced the idea of functionalism, an expansive approach to psychology that underlined the Darwinian idea of a behavior's usefulness to the individual. In 1890, James wrote an influential book, The Principles of Psychology, which expanded on the structuralism. He memorably described "stream of consciousness". James's ideas interested many American students in the emerging discipline. Dewey integrated psychology with societal concerns, most notably by promoting progressive education, inculcating moral values in children, and assimilating immigrants.