New research by Ragen McGowan et. al. from the University of Agricultural Sciences, Sweden, investigates whether dogs enjoy the experience of solving a problem in order to obtain a reward, or if it is just the reward itself that makes them happy.
Rather unusually, the idea came from a study that found cattle who completed a task to earn a reward seemed to be happier than those who just received the reward. The design of McGowan et al.’s study is very similar, but adjusted for dogs.
The results show that when dogs solved the problem and earned a reward they wagged their tails more and were more eager to repeat the experience than if they were just given a reward. The study also found that food was a preferred reward over time with another dog and petting from a familiar human.
Six matched pairs of beagles took part (12 dogs in total). Each dog was an experimental dog for half of the time, and a control dog for the other half of the time.
The study used six pieces of equipment. When manipulated correctly by the dog, each made a distinct noise that would show the task was complete. The equipment included a dog piano that had to be pressed to play a note, a plastic box to be pushed off a stack so it would noisily hit the floor, and a paddle lever that would make a bell ring.
When dogs solved the problem and earned a reward they wagged their tails more and were more eager to repeat the experience than if they were just given a reward.
Before the experiment, each dog was trained on three of the pieces of equipment while their matched pair was trained on the other three. The paired piece of equipment was present during training sessions, but the dog did not get rewards for interacting with it.
In the experiment itself, both pieces of equipment were again present, but the situation was new.
The experimental room had a start arena with the equipment, and a gate to a runway that led to the reward. An experimenter was hidden away, ready to open the gate at the appropriate time. An assistant led the dog into the start arena, then turned their back and did not interact with them further. When the experimental dog performed the behavior it had been trained to do, the gate opened to give access to the ramp leading to the reward.
When it was the dog’s turn to be a control, it did not matter what it did with the equipment. The gate opened after the length of time it had taken the matched experimental dog to solve the puzzle, so the dog spent the exact same amount of time in the start arena as their pair. They also got the exact same reward their pair had obtained. In other words, the only difference between the conditions was whether or not their manipulation of the equipment would have an effect on the gate opening.
The experimental dogs were keen to get to the start arena and usually went into the room ahead of the assistant. On the other hand, the scientists noticed that the control dogs “were initially eager to enter the room during their first two or three test runs, but soon grew reluctant to enter the test room. By the end of the test sessions, these dogs would enter the start arena only after some coaxing from the handler.”
There were other signs that dogs in the control condition were less happy than those in the experimental condition. They were less active in the start arena. They would sometimes bite or chew on the equipment, which dogs never did in the experimental condition. Once the gate had opened, they were quicker to enter the runway and leave the start arena than dogs in the experimental condition. There were no differences in mean heart rate, however.
There was more tail wagging when dogs were in the experimental condition, which also suggests they were happier.
When the reward was food or time with another dog, the control dogs were quicker to exit the start arena. There was no difference between experimental and control dogs if the reward was petting by a human they knew. But dogs in both conditions were more active when expecting a food reward, suggesting this was preferred. This is consistent with earlier studies that found dogs prefer food to petting (Okamoto et al., 2009; Fukuzawa and Hayashi, 2013; Feuerbacher and Wynne, 2012, who also looked at hand-reared wolves).
When dogs were controls, they still received a reward but they did not have any control over their environment. Perceived lack of control is stressful for humans, so perhaps it is for dogs. In fact, toward the end of the study, some of the dogs were successfully manipulating the item they had not been trained on, although of course this had no effect on the gate.
In the experimental condition, however, dogs were able to solve the problem and make the gate open. I am not sure if it is problem-solving, the fact it gave them control, or a combination of both that made dogs happy.
"The experimental animals in our study were excited not only by the expectation of a reward, but also about realizing that they themselves could control their access to the reward," the researchers write. "These results support the idea that opportunities to solve problems, make decisions, and exercise cognitive skills are important to an animal’s emotional experiences and ultimately, its welfare.”
Because differences in behavior were found in the start arena, they relate to the dog learning that it can open the gate by manipulating the equipment. The scientists call it a “Eureka moment.”