(Originally written for DogWatch, a newsletter for the general public from the Cornell University College of Veterinary Medicine)

I sometimes think that my black lab, Karl, would retrieve sticks until he dropped if I’d let him. My mom says this is addictive behavior and that I should stop playing with him this way before he develops serious problems. My feeling is that he’s far more likely to develop problems if I don’t allow him this outlet for all of his energy. Who’s right?

So much media attention has been showered on addictive or compulsive behaviors that we often lose sight of the fact that mammalian brains possess both addictive and non-addictive centers, and that the two function quite differently. Once experimental animals learn hit a key to stimulate their addictive centers, they’ll continue doing this even when researchers disconnect the apparatus. In similar experiments involving self-stimulation of the nonaddictive center however, the animal may try to trigger the pleasurable response a few times after the stimulator is disconnected, but it soon gives up and does something else.

In the most general of terms we may say that the addiction center triggers the recognition, “I feel happy because I’m pressing this key,” whereas the nonaddictive center triggers the message, “I feel happier when I’m pressing this key but it’s not the end of the world when I can’t.”

From this we can see that if Karl’s retrieving triggers the addiction center, he’ll see retrieving as the cause of any positive feelings he may experience. Because of this when he can’t do that he’ll feel frustrated and out of sorts. And that will cause him to do everything in his power to get his owner, or someone, to throw a stick for him to relieve those negative feelings. On the other hand, if the behavior stimulates his nonaddictive center, he’ll relish a game of retrieving just about any time. But when his owner says, “Time to quit” or calmly ignores him, he’ll find some other way to amuse himself because he doesn’t depend on the game for his feelings of well-being.

Sadly research into the workings of the nonaddictive center far lags that of the addictive, but it does appear that the two may work in tandem. For example, Karl may initially retrieve sticks because his Labrador breeding programs him for it and he enjoys it, a nonaddictive response. However suppose Karl’s owner feels compelled to throw every single stick that Karl drops at his feet and lavishly praises the dog for retrieving it and he feels the need to keep her focused on him for some reason. Under these circumstances, what begins as Karl’s random celebration of his normal Lab retrieving genes could evolve into a stylized ritual that carries a much stronger emotional charge. In this case, Karl might become so dependent on that interaction with his owner that he feels greatly stressed when his owner can’t or won’t play the game. In these situations, he may  relentlessly pester the owners to toss the stick again.  If denied this, he may attempt to relieve the resultant tension by chewing on the stick, or even his feet or the rug if she takes him instead where there are no  sticks.

One owner described how her male German shepherd dog made such a strong connection between retrieving and his mental health that he automatically would reach for his ball indoors or a stick outdoors if anything upset him. If he couldn’t immediately locate a stick outdoors, he’d leap up and snap branches off trees. While such an image might make us laugh, this very observant owner could tell from her dog’s tense body language and expression that this wasn’t a game to the dog at all. He needed whatever mental fix retrieving those sticks gave him.

Because of all this, we need to evaluate Karl’s seemingly compulsive stick-retrieving in the context of his other behaviors, his relationship with his owner, and his environment. If ending the game obviously distresses the dog, this canine response could presage more serious behavioral problems down the line. If Karl can accept the end of the game, but his owner feels compelled to continue it, then the owner should reevaluate her relationship with her pet. And finally, if Karl becomes seemingly obsessed with fetching sticks because these represent his only viable outlet for his energy, then providing him other options will allow the game to serve as a canine celebration rather than an obsession.