Final answer:
The procedure is known as negative reinforcement, a type of operant conditioning where a behavior is strengthened by stopping, removing, or avoiding a negative outcome or aversive stimulus.
Step-by-step explanation:
The procedure being used when the rat presses a lever to turn off a mild electric shock is called negative reinforcement. This is a type of operant conditioning, a concept developed by B.F. Skinner. In this scenario, the removal of an aversive stimulus (the electric shock) following the rat's action (pressing a lever) increases the likelihood that the rat will repeat the action in the future. Negative reinforcement should not be confused with punishment as it increases the frequency of a behavior, while punishment aims to decrease it.
Additionally, it is important to understand that the electrical shock applied in such experiments is generally mild and within safety guidelines to avoid harming the animal, taking into consideration the 5-mA value for maximum allowed shock for safety. The Skinner box is the typical setup used for these kinds of operant conditioning experiments. Learned behaviors and conditioning can be analyzed over time, as in the case of the experiment involving different responses of rats to environmental cues and the expression of different proteins activated by light flashes at varying frequencies.