Often students begin with a sort of backwards way of looking at behavior. They can't believe that, "I've punished him for doing this (jumping up, barking, destroying shoes) so many times, but still, he does it!"
In behavior science, the major principle says that behavior which is reinforced is strengthened and repeated, whereas behavior which is punished decreases.
True, the results of punishment are less predictable than the results of reinforcement, because it's hard to target punishment, animals adapt to punishment, there are so many ways to escape punishment, and also because dogs don't think like you do. You think you're yelling at (punishing) the dog for barking, but he thinks you're cute when you bark and come running. Or you shove the dog when he jumps up, and he shoves you back! The dog thinks this is a fun game! Dogs roughhouse when they play all the time, they just can't understand why you are such a grumpy player. Most often, "punished" dogs become increasingly anxious by the confusing behavior of their owners. Yelling, collar jerks, shoving or any sign of handler distress generally worries and punishes some canine behaviors, for example, the dog might not come when called anymore, or the dog won't cheerfully give up a shoe or a bone anymore, but those weren't the problem behaviors the owner intended to punish.
More predictable results occur when you analyze the behavior. Explore, "what is reinforcing this behavior?" Then take away the reinforcement from the undesirable behavior, reinforce the more desirable behaviors, and tada, almost overnight you will see a change.
Here's some homework. Look at any canine behavior. What is reinforcing it? Example: Often, dogs jump up because being near you, touching you, playing with you feels good. And when the dog stays on all four paws, you don't touch or play with him. Switch it around. Physically avoid the jumper (maybe clip him on a tether, and step out of reach when a paw starts to come off the ground), but pounce on and generously, frequently love up the dog who's got all four feet on the ground. Predictably, you'll soon have a dog who eagerly glues himself to the floor whenever you pass by.
