Final answer:
Ivan Pavlov and John B. Watson both underestimated the roles of biological constraints and cognitive processes in classical conditioning, focusing primarily on observable behaviors.
Step-by-step explanation:
Ivan Pavlov and John B. Watson underestimated the impact of biological constraints on classical conditioning, and they underestimated the impact of cognitive processes on classical conditioning.
This answer choice aligns with the historical perspectives of these two individuals in psychology. Pavlov, known for his work on classical conditioning through his salivation experiments with dogs, did not focus on the biological limitations of conditioning. Similarly, Watson, aligned with the behaviorist school of thought, emphasized the importance of observable behaviors over internal mental processes. Both researchers hence paid little attention to the inherent biological constraints and cognitive processes that could influence conditioning.