PSYCHOLOGY

After World War II

After , American psychology, particularly clinical psychology, grew into a substantial field in its own right, partly in response to the needs of returning veterans. The growth of psychology as a science was stimulated further by the launching of in 1957 and the opening of the Russian-American space race to the . As part of this race, the U.S. government fueled the growth of science. For the first time, massive federal funding became available, both to support behavioral research and to enable graduate training. Psychology became both a thriving profession of practitioners and a scientific discipline that investigated all aspects of human social behaviour, , and individual differences, as well as the areas of animal psychology, , , , and learning.

Training in was heavily influenced by Freudian psychology and its offshoots. But some clinical researchers, working with both normal and disturbed populations, began to develop and apply methods focusing on the learning conditions that influence and control social behaviour. This movement analyzed problematic behaviours (e.g., , bizarre speech patterns, , fear responses) in terms of the observable events and conditions that seemed to influence the person's problematic behaviour. Behavioral approaches led to for therapy by working to modify problematic behaviour not through insight, awareness, or the uncovering of unconscious motivations but by addressing the behaviour itself. Behaviourists attempted to modify the maladaptive behaviour directly, examining the conditions controlling the individual's current problems, not their possible historical roots. They also intended to show that such efforts could be successful without the symptom substitution that Freudian theory predicted. Freudians believed that removing the troubling behaviour directly would be followed by new and worse problems. Behaviour therapists showed that this was not necessarily the case.

To begin exploring the role of in and , psychologists compared the similarity in personality shown by people who share the same or the same . studies compared monozygotic (identical) as opposed to dizygotic (fraternal) twins, raised either in the same or in different . Overall, these studies demonstrated the important role of in a wide range of human characteristics and traits, such as those of the , and indicated that the biological-genetic influence was far greater than early behaviourism had assumed. At the same time, it also became clear that how such are expressed in behaviour depends importantly on interactions with the environment in the course of development, beginning in utero.