Reinforcement is anything that strengthens a behavior. There is both positive and negative reinforcement. Positive reinforcement adds something desirable to the situation that encourages that subject to repeat the behavior. A negative reinforcement removes something that is unpleasant to the subject from the situation. Both positive and negative reinforcement reward the subject. They strengthen behavior.
This is different from punishment which decreases behavior. Positive punishment gives something to the subject that the subject does not like if they do not do the correct behavior. Negative punishment is taking something away from the subject that they enjoyed.
Reinforcement has been found to a more successful way for getting subjects to repeat a certain behavior because it rewards them for doing the correct thing. Punishment is also successful, but not as much because it can only teach a subject what not to do.
I have used both reinforcement and punishment on my dog, Chloe. Electric fences are positive punishment. I used these on her to make her stop running out of our yard. If she crossed the property line she was given a small shock. After crossing once, she never did it again. A beeping noise also goes off when she gets close to the electric fence. Chloe has associated this noise with the shock (classical conditioning) and will turn around whenever she hears it. I also taught Chloe some tricks with positive reinforcement. Through shaping I was eventually able to teach Chloe how to roll over. Every time she completed the task successfully I would give her a treat (normally a piece of cheese). This turned into a problem though because I might’ve made her do the trick too many times. For a while after teaching her how to roll over, Chloe would start rolling over and over and over every time someone in my family got some cheese from the refrigerator. She wouldn’t stop until they gave her the cheese or picked her up. Once I think she did 6 or 7 spins before I stopped her. Thankfully this only lasted a few days. She stopped this dizzying habit when we stopped responding to her.