Psychology is the scientific study of the mind and behaviour, according to the American Psychological Association. Psychology is a multifaceted discipline and includes many sub-fields of study such areas as human development, sports, health, clinical, social behaviour and cognitive processes.

Psychology is really a very new science, with most advances happening over the past 150 years or so. However, its origins can be traced back to ancient Greece, 400–500 years BC. Philosophers used to discuss many topics now studied by modern psychology, such as memory, free will vs determinism, nature vs. nurture, attraction etc.

In the early days of psychology there were two dominant theoretical perspectives regarding how the brain worked, structuralism and functionalism. Structuralism was the name given to the approach pioneered by Wilhelm Wundt (1832-1920), which focused on breaking down mental processes intro the most basic components. The term originated from Edward Titchener, an American psychologist who had been trained by Wundt. Wundt was important because he separated psychology from philosophy by analyzing the workings of the mind in a more structured way, with the emphasis being on objective measurement and control. Structuralism relied on trained introspection, a research method whereby subjects related what was going on in their minds while performing a certain task.

An American psychologist named William James (1842-1910) developed an approach which came to be known as functionalism, that disagreed with the focus of Structuralism. James argued that the mind is constantly changing and it is pointless to look for the structure of conscious experience. Rather, he proposed the focus should be on how and why an organism does something, that is the functions or purpose of the brain. James suggested that psychologists should look for the underlying cause of behavior and the mental processes involved.