Bugs is an Australian Shepard puppy. Bugs has recently been classically conditioned to ring a large red bell attached to the door when she needs to go outside to potty. Unfortunately, her red bell broke. When Bugs' owner went to the store to get a new bell, they were out of the large red bells. They did have a small gold bell that would fit around the door. Bugs' owner was worried that she would not remember what to do because the bell was so different and new. Bugs successfully used the new bell soon after it was installed. This is an example of: