Q.Give a brief account of the evolution of psychology.

Modern psychology's formal beginning is usually dated to 1879, when Wilhelm Wundt founded the first experimental psychology laboratory in Leipzig, studying the mind's structure through introspection.

Modern psychology grew out of a much older tradition of philosophical inquiry into questions of genuine psychological significance, but its formal life as an experimental science is usually dated to 1879, when Wilhelm Wundt founded the first psychology laboratory in Leipzig, Germany. Wundt sought to analyse the basic structural building blocks of conscious experience using introspection -- asking trained subjects to describe their own mental processes in careful detail -- and psychologists working this way became known as structuralists. Because introspective reports could not be independently verified by an outside observer, structuralism was eventually judged too subjective, opening the way for several competing schools of thought.

William James, working in the United States at almost the same time, developed functionalism, which asked not what the mind is structurally made of but what it does -- how mental processes and behaviour help a person adapt to their environment and satisfy their needs. In the early twentieth century, Gestalt psychology emerged in Germany as a direct reaction against structuralism, arguing that perceptual experience is always more than the sum of its separate components (a rapid sequence of still film images, for instance, is perceived as one smooth, continuous scene). Around 1910, behaviourism, led by John Watson and drawing on Ivan Pavlov's work on classical conditioning, rejected mind and consciousness altogether as unscientific, insisting that psychology study only observable, measurable stimulus-response behaviour; B.F. Skinner later extended and popularised this approach, and behaviourists dominated the field for several decades.

Alongside behaviourism, Sigmund Freud developed psychoanalysis around 1900, portraying behaviour as driven by unconscious desires and conflicts and building it into a system for treating psychological disorders. Reacting against both Freud's view and behaviourism's mechanistic picture of human beings, humanistic psychologists such as Carl Rogers and Abraham Maslow took a more positive view of human nature, emphasising free will and a natural striving toward growth. Finally, elements of the Gestalt and structuralist traditions combined into the cognitive perspective, which studies cognition (thinking, perceiving, remembering, problem-solving), sometimes modelling the mind as an information-processing system like a computer; Piaget's constructivism and Vygotsky's socio-cultural theory of mind both belong to this broader cognitive tradition.