In recent years harnesses have become increasingly popular. I’ve written, many times, on the risks of applying pressure to the dog’s neck, see my blog here, but I don’t think I’ve ever suggested the use of a harness (or seen others do so) without some people voicing concerns that a harness will teach/encourage the dog to pull. People often comment that their trainer told them harnesses cause pulling, or that harnesses were originally designed for pulling. So, let’s evaluate each of these ideas.
Firstly, the fact that a trainer said something doesn’t make it a fact. I’m a qualified behaviourist, but I don’t agree with everything that all other qualified behaviourists say. We may have interpreted things differently. There are a great range of trainers, from those who promote shock collars to those who promote only force-free. The industry is very much unregulated, and some trainers stand at polar opposites to each other on methods, knowledge, skills, and ethics. Whatever side of the fence you might be on, it is clear to us all that what anybody says to you needs some degree of evaluation and is not necessarily entirely accurate.
The notion that the harness was designed for sled dogs to pull is entirely correct. The reason for using a harness for sledding is simply ergonomics. Sled dogs pull heavy weights, it’s fairly obvious that pulling heavy weights via a neck collar would be much less efficient and much less comfortable for the dogs. Therefore, I think the question we must ask is, do we want to make pulling uncomfortable? If the answer is yes, then I guess it’s because you believe that making it uncomfortable will reduce or stop the pulling. Apart from the fact that this would be using aversives to control behaviour (which many don’t agree with), it doesn’t seem to work very well. The problem of pulling occurs very commonly in dogs that have only ever been walked on a collar, and the same goes for the harness. If dogs on collars didn’t pull, the harness would never have become commonplace for companion dogs, because there wouldn’t have been any discomfort or medical concerns.
Dogs pull whether you make it less comfortable or not. There are two main reasons for this. The first is a lack of training, which may also include behavioural issues and emotional issues. And secondly, there is a natural tendency in most mammals (if not all) to pull against pressure. If somebody grabs your arm and starts walking away, you will naturally resist by pulling in the opposite direction.
After reflecting on this issue many times, my view is that the harness does not cause pulling, it probably makes pulling more comfortable but that isn’t the same as encouraging it. For example, my previous car was uncomfortable on long journeys; I didn’t stop making those journeys, I was just less comfortable and more irritable when I drove. This is because aversive events do not always reduce or prevent problematic behaviour, as is often believed.