World War II brought about a technical revolution in communication and electronics.
Led by people such as British mathematician Alan Turing
researchers developed mechanical computing devices to crack wartime codes and solve complex mathematical problems.
In the 1950s and 1960s, scientists applied these ideas to the study of human behavior.
The result is called the “cognitive revolution”
a movement of psychologists who used ideas from computer science and other disciplines
as a way to understand mental processes such as perceiving, remembering, and thinking.
This change in focus had a number of pioneers, including Jean Piaget, a Swiss psychologist
who in the 1930s and 1940s had studied the perceptual and cognitive errors made by children of different ages.
One of his key works, The Origins of Intelligence in Children, appeared in 1952
the same year that neuroscientists Alan Hodgkin and Andrew Huxley
published their paper describing the action potential in neurons.
Psychologists began to compare the brain and its component neurons to a computer and its circuits
focusing on their common abilities to register, store, and retrieve information.
In 1958, this led English psychologist Donald Broadbent
to publish a book arguing that humans process information in a way analogous to computers.
Two years earlier, George Miller had published an article on “The Magical Number Seven”
describing limitations in many mental processes, including the number of items a person can hold in memory.
These and many other developments expanded the definition of psychology
to the “science of behavior and mental processes.”
The cognitive revolution challenged behaviorism, as did a second movement called humanistic psychology
an approach that emphasizes the positive potential of human beings.
Psychologists such as Abraham Maslow and Carl Rogers argued that humans were not rats or robots
but had aspirations and capabilities far beyond those studied by behaviorists.
In 1943 Maslow published his theory of a “hierarchy of needs"
ranging from basic physiological needs to the highest need for self-actualization
to describe human motivation.
Rogers published his ideas about “client-centered therapy” in 1951
describing it as a way to help people reach their potential to become fully-functioning persons.