Question

every time mr. harrison gets a headache he takes an aspirin that helps his headache. this is an example of ___________________________.
spontaneous recovery
fixed - interval
instinctive drift
negative reinforcement

Explanation:

Negative reinforcement involves removing an aversive stimulus (in this case, the headache) to increase the likelihood of a behavior (taking aspirin). Spontaneous recovery is the reappearance of a previously extinguished conditioned response. Fixed - interval is a schedule of reinforcement. Instinctive drift is the tendency of an animal to revert to instinctive behavior.

Answer:

Negative reinforcement