What significant development occurred in the 1940-1949 decade related to psychology?

During the decade of 1940-1949, one of the significant developments in psychology was the formation of accreditation bodies. This movement was crucial in establishing standards for training and practice in the field of psychology, which in turn contributed to the profession's credibility and professionalism. Accreditation bodies helped to ensure that educational programs met specific standards of quality and provided essential guidelines for ethical practice.

The establishment of accreditation bodies was instrumental in the post-war expansion of psychological services and education. With a growing recognition of mental health issues and the importance of psychological services, having accredited programs became vital for training competent professionals in various areas, including school psychology. This shift not only impacted practitioners but also greatly influenced the public's perception of psychology as a legitimate and important field of study.

While other options represent relevant events or topics in the field, the formation of accreditation bodies in this particular decade marks a foundational step toward the professionalization and regulation of psychology as a discipline.