Arat presses on a level, only to find that the electric shock under his feet is terminated. the rat continues to press on the lever. this is an example of

The above is an example of negative reinforcement. It is a term depicted by B. F. Skinner in his hypothesis of operant molding. In negative fortification, a reaction or conduct is reinforced by halting, expelling or dodging a negative result or aversive jolt. 

It happens when a specific boost is evacuated after a specific conduct is displayed. The probability of the specific conduct happening again, later on, is expanded on account of evacuating/maintaining a strategic distance from the negative outcome.