Answer:
John B. Watson
Step-by-step explanation:
Watson studied the findings made by Ivan Pavlov at the same time as his doctorate, and developed similar research in animal biology, physiology, and behavior, as well as child behavior, concluding that human behavior was in many ways similar to animal behavior. Based on this finding and inspired by Pavlov's discoveries, he created within Psychology a new current, Behaviorism. According to him, the behavior of complex organisms responds to situations according to their nervous network, which is conditioned by experience. Based on this, we can conclude that when Fred insists that he can turn any reasonably healthy individual into an internationally competitive tennis player, Fred is echoing Watson's thoughts.