an event or behavior whose reinforcing properties are associated with its removal

an unpleasant or painful stimulus which the horse can avoid by changing it's behavior

Something which is removed and the behavior immediately preceding the removal increases in frequency. Example: I pinch my dog's ear and the instant he takes the dumbbell I stop pinching. If the behavior "taking the dumbbell" increases, then the ear pinch was a negative reinforcer.

Any stimulus that, when removed following a response, increases the probability of the response. Loud noises, electric shock, and extreme heat or cold classify as negative reinforcers. See also punishment.