History of psychology

The study of psychology in a philosophical context dates back to the ancient civilizations of Egypt, Greece, China and India. Psychology began adopting a more clinical[1] and experimental[2] approach under medieval Muslim psychologists and physicians, who built psychiatric hospitals for such purposes.
Beginning of scientific psychology

Though the use of psychological experimentation dates back to Alhazen’s Book of Optics in 1021,[2][4] psychology as an independent experimental field of study began in 1879, when Wilhelm Wundt founded the first laboratory dedicated exclusively to psychological research at Leipzig University in Germany, for which Wundt is known as the “father of psychology”.[5] 1879 is thus sometimes regarded as the “birthdate” of psychology. The American philosopher William James published his seminal book, Principles of Psychology,[6] in 1890, while laying the foundations for many of the questions that psychologists would focus on for years to come. Other important early contributors to the field include Hermann Ebbinghaus (1850–1909), a pioneer in the experimental study of memory at the University of Berlin; and the Russian physiologist Ivan Pavlov (1849-1936), who investigated the learning process now referred to as classical conditioning.
Auguste Rodin's The Thinker, bronze cast by Alexis Rudier, Laeken Cemetery, Brussels, Belgium.

Meanwhile, during the 1890s, the Austrian physician Sigmund Freud, who was trained as a neurologist and had no formal training in experimental psychology, had developed a method of psychotherapy known as psychoanalysis. Freud’s understanding of the mind was largely based on interpretive methods, introspection and clinical observations, and was focused in particular on resolving unconscious conflict, mental distress and psychopathology. Freud’s theories became very well-known, largely because they tackled subjects such as sexuality, repression, and the unconscious mind as general aspects of psychological development. These were largely considered taboo subjects at the time, and Freud provided a catalyst for them to be openly discussed in polite society. But Karl Popper argued that Freud’s psychoanalytic theories were presented in untestable form.[7] Due to their subjective nature, Freud’s theories are of limited (mostly historical) interest to modern academic psychology departments. Followers of Freud who accept the basic ideas of psychoanalysis but alter it in some way are called neo-Freudians.
Rise of behaviorism

Partly in reaction to the subjective and introspective nature of Freudian psychodynamics, and its focus on the recollection of childhood experiences, during the early decades of the 20th century, behaviorism gained popularity as a guiding psychological theory. Founded by John B. Watson and embraced and extended by Edward Thorndike, Clark L. Hull, Edward C. Tolman, and later B.F. Skinner, behaviorism was grounded in animal experimentation in the laboratory. Behaviorists shared the view that the subject matter of psychology should be operationalized with standardized procedures which led psychology to focus on behavior, not the mind or consciousness.[8] They doubted the validity of introspection for studying internal mental states such as feelings, sensations, beliefs, desires, and other unobservables.[8] In “Psychology as the Behaviorist Views It” (1913),[9] Watson argued that psychology “is a purely objective experimental branch of natural science,” that “introspection forms no essential part of its methods”, and that “the behaviorist recognizes no dividing line between man and brute.” Skinner rejected hypothesis testing as a productive method of research, considering it to be too conducive to speculative theories that would promote useless research and stifle good research.[10]

Behaviorism reigned as the dominant paradigm in psychology throughout the first half of the 20th century. However, the modern field of psychology is largely dominated by cognitive psychology. Linguist Noam Chomsky helped spark the cognitive revolution in psychology through his review of B. F. Skinner’s Verbal Behavior, in which he challenged the behaviorist approach to the study of behavior and language dominant in the 1950s. Chomsky was highly critical of what he considered arbitrary notions of ’stimulus’, ‘response’ and ‘reinforcement’ which Skinner borrowed from animal experiments in the laboratory. Chomsky argued that Skinner’s notions could only be applied to complex human behavior, such as language acquisition, in a vague and superficial manner. Chomsky emphasized that research and analysis must not ignore the contribution of the child in the acquisition of language and proposed that humans are born with an natural ability to acquire language.[11] Work most associated with psychologist Albert Bandura, who initiated and studied social learning theory, showed that children could learn aggression from a role model through observational learning, without any change in overt behavior, and so must be accounted for by internal processes.[12]
Existential-humanist movement

Humanistic psychology was developed in the 1950s in reaction to both behaviorism and psychoanalysis, arising largely from existential philosophy and writers like Jean-Paul Sartre and Søren Kierkegaard. By using phenomenology, intersubjectivity and first-person categories, the humanistic approach seeks to get a glimpse of the whole person and not just the fragmented parts of the personality or cognitive functioning.[13] Humanism focuses on uniquely human issues and fundamental issues of life, such as self-identity, death, aloneness, freedom, and meaning. Some of the founding theorists behind this school of thought were Abraham Maslow who formulated a hierarchy of human needs, Carl Rogers who created and developed Client-centered therapy, and Fritz Perls who helped create and develop Gestalt therapy. It became so influential as to be called the “third force” within psychology (preceded by behaviorism and psychoanalysis).[14)
Cognitivism

The rise of computer technology also promoted the metaphor of mental function as information processing. This, combined with a scientific approach to studying the mind, as well as a belief in internal mental states, led to the rise of cognitivism as a popular model of the mind.

Cognitive psychology is radically different from previous psychological perspectives in two key ways.

* It accepts the use of the scientific method, and generally rejects introspection as a valid method of investigation, unlike symbol-driven approaches such as Freudian psychodynamics.
* It explicitly acknowledges the existence of internal mental states (such as belief, desire and motivation) unlike behaviorism.

Links between brain and nervous system function were also becoming understood, partly due to the experimental work of people such as Charles Sherrington and Donald Hebb, and partly due to studies of people with brain injury (see cognitive neuropsychology). With the development of technologies for accurately measuring brain function, neuropsychology and cognitive neuroscience have become some of the most active areas in contemporary psychology[citation needed]. With the increasing involvement of other disciplines (such as philosophy, computer science and neuroscience) in the quest to understand the mind, the umbrella discipline of cognitive science has been created as a means of focusing such efforts in a constructive way.