Answer:
The perspective that dominated American psychology for decades was b. behaviorism.
Step-by-step explanation:
Behaviorism was a dominant school of thought in American psychology from the early 20th century through much of the 20th century. It emphasized the study of observable behaviors and the influence of the environment on behavior, while largely ignoring mental processes and consciousness. While other perspectives like cognitive theory and social psychology have also been influential, behaviorism had a particularly strong influence on the field for a significant period of time.