Final answer:
The psychological theory known for using animal research to draw conclusions is Behaviorism, pioneered by figures such as Pavlov, Watson, and Skinner.
Step-by-step explanation:
The theory that primarily used animal research to draw theoretical conclusions is Behaviorism. Beginning with the work of Ivan Pavlov and his experiments on conditioned reflexes, behaviorism focused on studying and modifying overt behavior through reinforcement and association, often using animal subjects. Later, influential psychologists like John B. Watson and B. F. Skinner further developed the field, with Watson advocating for a purely objective psychology that disregards unobservable mental processes, and Skinner's work on operant conditioning providing detailed analysis of the effects of rewards and punishments on behavior.