There were novel stimuli present in Chicago that weren't present at home and that interfered with Kara's chain.
Step-by-step explanation:
The latest stimuli preserve all the important attributes of the original stimuli. This is a Google scholar example and can be reused underneath a CC BY-SA license. Until undertaking his study, he observed that the introduction of all species to a new stimulus initially created apprehension/avoidance.
For example, animals are trained to use a similar reward as a differential predictor and then evaluated by using a new stimulus, which can in one or more ways mimic a training cue. When the subject responds to a research stimulus in the same manner as the stimuli, it is said that the stimulus is replicated. Generalization might be complete or partial and may represent both qualitative as well as quantity variations among stimuli (e.g. colour and visual stimulus brightness).