What school of psychology dominated during the first half of the 20th century?

Behaviorism is recognized as the dominant school of psychology during the first half of the 20th century due to its emphasis on observable behaviors and the idea that all behaviors are learned through interaction with the environment. Pioneered by figures such as John B. Watson and B.F. Skinner, behaviorism focused on measuring and influencing behavior rather than introspection or the study of conscious experience. This approach revolutionized psychology by introducing rigorous scientific methods, paving the way for experiments that could be replicated and verified.

The significance of behaviorism lies in its foundational principles that still influence many areas, such as educational practices and behavioral therapy. This period saw a shift from the more subjective approaches of earlier psychological theories, fundamentally changing how psychological phenomena were studied and understood.

Other schools of thought, like humanism, cognitive psychology, and Gestalt psychology, emerged either concurrently or later, but they did not achieve the same level of prominence until after behaviorism had established its principles and methodologies. Each of these other approaches has its importance and contributions, but during the early to mid-20th century, behaviorism set the framework for much of psychological research and practice.