Anyone who has adopted a puppy knows that they can be a handful. There are many ways to go about correcting negative behaviors and promoting positive ones, but in recent years, antiquated “aversive” training has been outpaced by reward-based reinforcement training, and a new study suggests that the benefits are many.

Aversive training is, for many people, an almost instinctual reaction to a dog that is misbehaving. You see your puppying gnawing on a piece of furniture and you yell. The pup stops what they were doing and eventually learns to fear the consequences of those negative actions. It can work, but there may be unintended side effects.

The study, which focused on stress responses in puppies who were trained using either aversion techniques or positive reinforcement methods. Using a sample size of 92 dogs from seven different training schools that used one of the two training methods, the researchers tallied the number of stress-related behaviors from each dog during and after a training session.

What they found was that the dogs trained using the aversive method displayed significantly more stress behaviors — including lip licking, yawning, and paw-raising — than the pups trained without yelling or leash-yanking. This was true both during and after training, suggesting that the elevated stress levels of the dogs don’t return to normal even when the dogs returned home.

This is a significant finding on its own, but the researchers went the extra set of sampling the stress hormone levels of each animal over the course of their observations. In the dogs who were trained using the aversive method, the levels of the stress hormone cortisol were elevated during training.

An additional experiment tasked the dogs with seeking out a bowl that contained a treat in a room. The dogs were trained to know that when the bowl was on one side of the room, a treat was present, but that the bowl was empty if it was on the other side of the room.

The bowl was then placed at random locations in the room to see how the dogs would react. The pups who endured aversion training were much more pessimistic and avoided the bowl at a higher rate than those who were trained with the reward-based method. The researchers interpret this as the more stressed dogs having a depressive mindset.

If nothing else, this research shows that reward-based training has some significant advantages over the older method, and it’s something to consider if you recently welcomed a new puppy into your home.