When one or more stimuli are presented at once, only one stimuli might become the conditioned response, which is known as overshadowing. In the current experiment, the goal was to test overshadowing of the stimuli. Three experiments were conducted on Sniffy the Rat, two of which were control experiments for the third experiment. The first two experiments used different stimuli, the first was tone and the second was light, paired with a shock. After the shock was removed, the first experiment involving the tone became the conditioned response, and in the second the tone was conditioned but eventually habituated. The third experiment paired a high level of light and a low level of tone along with a shock. After the shock was removed, the tone
