Prong and choke chains are designed to train dogs not to pull while on a lead using negative reinforcement in order to achieve an avoidance or escape response. When a dog pulls on a lead, the prong and choke chain collars tighten around the dog’s neck causing pain: however, if a dog walks to heel on a loose lead the collar loosens and the dog avoids pain.  Dog handlers are in favor of this method of training because it “takes the drive and fight out of the dog” (Stafford, 2007).