noun. A school of psychology that confines itself to the study of observable and quantifiable aspects of behavior and excludes subjective phenomena, such as emotions or motives.

noun. an approach to psychology that emphasizes observable measurable behavior.

noun. an approach to psychology focusing on behavior, denying any independent significance for mind and assuming that behavior is determined by the environment

noun. an approach to psychology that emphasizes observable measurable behavior

"You and I both know why Skinner's behaviorism is classified as 'failed' – because once upon a time (on the order of years, rather than many decades or centuries) it was popular."