What is which word was supposed to be cat?

As an AI language model, I am not sure about the exact context of your question. However, assuming that you are referring to an experiment conducted by J.B. Watson, wherein he conditioned a young boy to fear a white rat by associating it with a loud noise, it is said that the word "cat" was one of the input words that was conditioned to evoke a fear response in the child. This was a part of Watson's theory of behaviorism that emphasized the role of learning and conditioning in shaping human behavior.