Final answer:
Phase 1 in the Skinner Box experiment involves operant conditioning where a rat learns to turn off an electric shock by pressing a bar, an example of negative reinforcement.
Step-by-step explanation:
In the Skinner Box experiment setup, Phase 1 describes a scenario where operant conditioning is at play. The rat, placed within the chamber, learns to associate the pressing of the bar with the immediate cessation of an unpleasant stimulus, which is the electric shock in this case. This phase of the experiment represents a negative reinforcement as the rat's action (pressing the bar) results in the removal of the electric shock, thereby increasing the likelihood of the behavior being repeated. Essentially, the rat is conditioned to understand that pressing the bar will stop the discomfort, thus influencing its future behavior in similar situations.