This will be a very short post because the reason why dogs are self-evidently much easier to train than cats can be delivered in a succinct way according to Dr Bradshaw. There are two reasons behind this well-known difference between dogs and cats.
Firstly, dogs find the simple act of human attention rewarding whereas cats “do not find human attention rewarding in its own right”. If this difference is true it must because the cat is essentially a solitary creature whereas the dog is a pack animal.
Because of this difference the reward when training a cat is nearly always food. For the dog it can be affection. I suppose the point being made here is that as a dog is rewarded by our affection it is much easier to provide the reward.
The reward of course is part of positive reinforcement in training.
Secondly, dog behavior can be “shaped” into something useful for humans. An example is the sheepdog herding sheep. This is a modification of the hunting behavior of the wolf, the dog’s wild ancestor. The various forms of cat behavior cannot be shaped or adopted in this way.
I think the point Dr Bradshaw is making is that we train dogs to do something useful for us whereas cats were domesticated to prey on rodents but they don’t need training for that; we let them get on with it. The only reason for training a cat is for our pleasure. There appears to be no functional purpose to it.
Perhaps there is a third factor. Dogs are more needy than cats. The dog wants to please whereas the cat has a more take it or leave it attitude. The desire to please lends itself to being trained.