This is a very good article by Jessica Pierce:
“Are Ultrasonic Dog Training Devices Really Safe and Humane?“
One point of correction at the end of it: their following statement is incorrect.
“Food treats are good to start with but as training progresses your dog should recognise verbal praise and a pat as a treat.”
There is no inherent reason to stop reinforcing behaviors with things dogs prefer (food) and deliver something they may like but not as much (verbal praise and a pat). Each dog has preferences and may prefer different types of rewards at different times, but in general food-treats tend to be higher value to dogs than things such as praise.
Once a dog is further along in training, behaviors can be rewarded some of the time (intermittent reinforcement), which keeps the behaviors strong over time, and different types of rewards can be used including treats, toys, the chance to meet or play with other dogs, the chance to go on a walk or run off leash, or praise, gentle petting, etc.
But there is no reason to completely stop rewarding with food/treats.
Aversive training methods like ultrasonic devices and techniques designed to notice behavior problems and punish them, do harm dogs and can lead to additional problems. Dogs who are constantly, and often times randomly punished end up more uncomfortable. It’s common for dogs who are punished for barking to bark more, even though that’s not the person’s intended outcome.
Using positive reinforcement methods allows dogs to understand how the training process works (they perform behaviors for rewards), and then they can relax, leading to problems like upset-frustration barking simply vanishing or drastically decreasing.
It’s also important to address the underlying reason for barking. For example, if a dog has separation anxiety – an extreme phobia of being left alone – punishment only makes this worse. It just proves to the dog that being left alone is scary. Not only was there original extreme fear, but with electronic devices causing discomfort or pain, it just adds to dog’s mental suffering and anxiety. Instead we want to help these dogs desensitize to being left alone, to make them more comfortable and free from fear.
By Dan Raymer