Unfortunately, dogs don’t speak English (*sigh* I really thought we would have solved this by 2016), so to them, words are just sounds.
In a breakthrough study published in the scientific journal Current Biology, researchers reported that dogs, just like humans, process the emotional cue of a sound in a specific part of the brain. By playing different sounds while scanning a dog’s brain, researchers found that dogs respond more strongly to positive emotions than to negative emotions.
This makes sense, since most animals, including dogs and humans, use low pitched sounds to convey a threat or assert dominance. On the other hand, short, high-pitched sounds (think baby talk) are typically used in less-stressful situations.
I’m sure most pet parents have first hand experience with this, and know that a happy, high pitched voice can get a dog all riled up. Contrastingly, a low pitched or sharp sounding voice might make your dog cower or duck his tail.
So when it comes to training, which tone is best? Generally speaking, a happy, upbeat tone is best with positive reinforcement training. For example, by using an upbeat, excited tone when you give your do the cue “come!” you are encouraging excitement and energy. A low and aggressive tone on the other hand might sound threatening and make your dog stressed, nervous, or unresponsive.
There are times when a calm, authoritative (yet non-harsh) tone can help your dog succeed. For instance, when you give your dog a cue that requires them to show self-restraint, like “sit” or stay.” I know that if I say “sit” the same way I say “Let’s go!” there’s no way my dog’s wiggle-butt will ever reach the floor.
Volume is important but unless your dog is really far away, yelling at your dog is overkill, especially when paired with an angry or sharp tone. People often think that if a dog cowers or ducks his tail while being yelled at, that the dog understands A.) that he is in trouble, and B.) what he is in trouble for. In reality, your dog is probably cowering cause he is scared of your loud and angry voice.
Lastly, consistency of tone is critical, especially when your dog is still in the early stages of learning something new. Some dogs have to hear a new cue 50 to 100 times before they can proficiently respond with a behavior. In effect, it’s important to remember that the same word said in two different tones can sound like two completely different words.