Years ago punishment and negative based training was popular. Despite what we have learned in the last decade or two about training, some people have returned to these “old school” methods due to the popularity of recent TV shows and reality shows. Negative, dominance and fear based training only hinders your relationship with your dog. These methods confuse your dog, make your dog distrust you and can even cause aggression and behavior problems. For those that say “it works on TV”, for one it’s reality TV and you don’t see the before and after. Also studies show in addition to being detrimental to your relationship with your dogs, these methods do NOT work long term. Often people are fooled by the immediate result but the behavior does not continue and often gets worse. Punishment doesn’t work as a training method for teaching your dogs what to do and it often brings with it many unwanted side effects.

Still not convinced..here is some additional resources (click them to read):