Dog Self-Control Requires Energy Resources

In dogs, the energy spent in exercising self-control needs to be replenished.

Posted Jul 17, 2018

Jörg Kantel, Creative Content License
Source: Jörg Kantel, Creative Content License

For both humans and dogs, self-control, or what we commonly refer to as willpower, is an important ability. Without it we would give in to any momentary urges and be unable to direct our minds to important tasks. However research has shown that self-control in both dogs and people is a limited resource. Basically the findings are that every time you, or a dog, exercises mental restraint you spend some of your resources, which then makes it more difficult to perform mental tasks or engage in more restraint or self-control (click here for more about that). An example of this, which is familiar to anyone who has tried to go on a diet, is that in the beginning it is relatively easy to avoid eating tempting foods, but each time you are presented with a new temptation your ability to restrain yourself becomes more and more difficult. Each act of willpower leaves fewer resources for the next act of self-control.

I was forced to think about this issue when I was confronted with a failure in canine self-control. Because several dog obedience competitions would be occurring over the next month and a half, I decided to put some extra training time into my young Nova Scotia duck tolling retriever, Ranger. So instead of training him at our dog club for his usual one-hour session, I decided to take him to two back-to-back hour-long classes. Each of the classes included some exercises that required self-control, such as "sit-stay" and "down-stay." Ranger made it through the first hour quite well and was doing OK during the second, although he seemed a bit more fidgety on the stay exercises later in the hour. We then moved on to practicing the recall exercise. I left him in a sit-stay and began to walk to the end of the room, some 40 feet away. Just as I turned to face him again, he glanced at me and then broke from his position, hurtling around the room at high speed, seemingly out-of-control. He was finally apprehended by one of the instructors before he got himself in trouble, but it was clear to me that the two hours of training had exhausted his self-control.

Watching my young dog break from his sitting position and careen around the training hall reminded me of the research reporting that self-control requires energy resources, which can be depleted. That set of research studies had been conducted by Holly Miller and a team of other scientists from the University of Kentucky in Lexington. Since they had established that exercising self-control drains resources, which then interferes with further self-control or other mental processes, I wondered whether they had taken the next step to see if those resources could be replenished quickly and efficiently. With this in mind I went back to the scientific literature and found another report by this research team which did exactly that.

This study actually consisted of two experiments. The first one provided a replication of the original findings that self-control drains resources and makes further mental activities more difficult. In this study dogs were shown a transparent plastic toy containing treats they could both see and smell. They were taught that they could get these treats by tugging on the toy. The dogs were then assigned to one of two conditions. The first was quite simple: The dog was placed in a wire kennel crate and left there for ten minutes with the owner out of sight. The second condition involved some willpower and self-restraint on the part of the dog. In this test condition the dog was placed in a sit-stay position and the owner left the room for ten minutes. If the dog began to move out of position, the owner returned, repeated the sit-stay command, and again disappeared from sight. Afterwards both groups of dogs were again given the toy from which they had learned how to get food, only this time the toy was set up so that no treats were dispensed regardless of how the dogs tugged at it. The idea was to measure how long the dogs would persist at this impossible task before they gave up. The findings were quite clear—the dogs who had to exert willpower by holding their position in the earlier part of the session rapidly lost their focus on the problem and gave up a lot more quickly. In fact, the dogs that had to exercise self-control persisted at the task only 34 percent as long as the dogs that didn't have to use up their energy in advance.

But what is this resource that is being exhausted by self-control? It turns out that research has shown that self-control in humans relies on the availability of blood sugar. It's recognized that the human brain depends on glucose in the blood for energy. All cognitive processes involve some expenditure of glucose, but activities that involve high levels of mental effort are particularly susceptible to fluctuations in the blood sugar level. These experiments on humans suggest that exerting self-control significantly lowers blood glucose levels, which in turn results in poor performance on tasks set after the exertion of willpower.

Well, if blood sugar levels are the issue, couldn't the needed mental resources be restored by consuming something sugary? The research on human beings shows that this in fact works, and consuming something like a sugar-laden drink restores performance. If this is true, then the negative effects in dogs of exercising self-control should be eliminated with a boost of glucose.

The research team confirmed this in a second experiment, which was identical to the first except that one group of dogs, who had to exercise self-control by sitting in place for 10 minutes, was given a high-sugar drink immediately afterwards, just a few minutes before being given the treat-filled toy. The results were unambiguous. The dogs who received the jolt of sugar now performed just as well as those who had not had to exercise self-control before being presented with a new task.

This appeared to me to be a very promising finding. So before the next evening when I hoped to train Ranger again for two hours, I armed myself with a small plastic bag filled with gummy candies (gummy bears and gummy worms). For those of you who are not familiar with these marvelously sweet and probably unhealthy treats, they are soft candies with a gelatin base, sweetened by a lot of corn syrup and sugar. According to the package one serving contains 21 grams of sugar.

Once again I took Ranger to his class, and as before, he got through the first hour quite well. During the break between classes, I took him out for five minutes or so to relieve himself, and I gave him a couple of the gummy candies I was carrying. This time, as he worked his way through the second hour of obedience training, he seemed less fidgety on the sit-stays and the down-stays—the self-control exercises. There were no breaks from position and no exciting mad dash around the room.

Although this is clearly just a report of my personal experience, not a controlled scientific observation, what I was doing was based on the research findings. In any event, I have now made it a habit to carry these gummy candies with me whenever I know that my dogs are going to have to exercise willpower in classes or obedience competitions. It seems like a simple way to boost the resources my dogs need to maintain self-control, and besides, they adore the taste of these highly sweetened treats.


Holly C. Miller, Kristina F. Pattison, C. Nathan DeWall,Rebecca Rayburn-Reeves, and Thomas R. Zentall (2010). Self-Control Without a “Self”? Common Self-Control Processes in Humans and Dogs. Psychological Science, 21(4) 534–538