As an aside, psychologically speaking, shocking a dog for misbehaviour is not 'negative reinforcement'. It's positive punishment.
Positive reinforcement is providing a reward for good behaviour, like a treat for a dog that obeys an instruction. Negative reinforcement is removing something as a reward for good behaviour, like removing something that would ordinarily happen but isn't desirable. Positive punishment, or just 'punishment' is adding something undesirable in order to discourage a behaviour, like smacking a child. Negative punishment is taking a pleasurable stimulus away, like 'no dessert' if you don't finish your dinner.