Your dog is running around the living room squeaking one of his favorite toys when you show up with a present from the pet store. You open the bag, show him the new plaything and it's no contest. The new toy is now his favorite toy.

Why are dogs so fickle when it comes to these inanimate objects?

Researchers have taken a serious look at the fun side of a dog's life and have discovered that most canines have a preference for novelty, a trait called neophilia.

In 2008, researchers from the University of Giessen in Germany and the University of Lincoln in the U.K. familiarized 17 dogs with two toys. The experimenters played with the dogs and the two toys to make sure they were interested in the playthings. The dogs were then shown three toys — the two they already knew and a brand-new one. Each dog was presented with three different line-ups that featured the two familiar toys plus an unfamiliar, new toy.

The dogs were let loose to approach the toys and sniff, pick up or play with whichever plaything they wanted. Newness won out big time. The dogs chose the unfamiliar toy in 38 out of 50 tests. The results of the study were published in the journal Animal Cognition.

The same concept was studied by researchers at the University of Bristol Anthrozoology Institute and the Waltham Center for Pet Nutrition who also published their study in Animal Cognition. They took 16 adult Labrador retrievers and presented each one with a toy for 30 seconds. The toy was taken away and then returned to the dog after a short time. This happened over and over until the dog became bored and no longer showed any interest in the toy. The dog was then given a new toy that either had a different color or odor and the exercise was repeated.

A variety of toys were used but it didn't seem to matter. On average, the dogs lost interest in the toys after five 30-second intervals of exposure. That's just 2 1/2 minutes of playing with the toy.

"It appears that once a dog is completely familiar with the sight, sound, feel, and smell of a toy it becomes rather boring," writes professor of psychology Stanley Coren, Ph.D. in Psychology Today.

Because the researchers presented the dogs with various types of toys, the researchers were able to draw some conclusions about their preferences.

"Because we think that dogs perceive toys in the same way that wolves perceive prey, they prefer toys that either taste like food or can be torn apart," said co-author John Bradshaw. (Think piles of stuffing all over your floor.)

Co-author, Anne Pullen, said the toys should be "soft, easily manipulable toys that can be chewed easily and/or make a noise. Dogs quickly lose interest in toys with hard unyielding surfaces, and those that don't make a noise when manipulated."

Making old toys 'new' again

dog playing tug with a toy Boring toys suddenly become interesting when you become part of the equation and play with your dog. (Photo: elbud/Shutterstock)

Although this research sounds like great news for pet toy manufacturers and bad news for your wallet, there are things you can do to your dog's current toys to keep them interesting, says Coren.

1. Rotate the toys. Out of sight, out of mind is true when it comes to playthings. Give your pet one or two toys and tuck the rest away. Then swap the toys out every day or couple of days. There are devoted dog parents who have tips on everything from the best system to the most efficient storage containers. (One tip: Don't keep the toys in an accessible drawer if you don't want your dog trying to scratch his way in.)

2. Change their smell. Take your dog's toys and roll them around in the grass or leaves. Or consider dusting them with a sprinkle of spices. Just do your research first to make sure the substances are safe for your pet.

3. Get involved. "Perhaps the best way to keep a plaything from becoming boring relies on the fact that you personally can make a difference in the interest value of the toy," says Coren. "Playing with your dog using that old toy can change the plaything's worth and the dog's interest in it." When you become part of the game, all of a sudden a toy becomes fun in a brand-new way.

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.