Is the bond our dogs seem to share with us just based on food -- people merely a way to score a snack -- or is there really a deeper relationship between humans and their smart canine friends?
That question was at the root of new research from scientists at Emory University.
"One theory about dogs is that they are primarily Pavlovian machines. They just want food and their owners are simply the means to get it," said the lead author of the study, Emory neuroscientist Gregory Berns, in a statement. "Another, more current, view of their behavior is that dogs value human contact in and of itself."
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To see if the latter view holds up, Berns and his team at the Dog Project in Emory's psychology department put a couple of toys and a common household item to good use. They trained a group of dogs to associate a toy truck with a food reward, a toy knight with verbal praise and a hairbrush with no reward as a control item.
Once trained on the items, it was time for each dog to spend some time in a functional magnetic resonance imaging (fMRI) scanner. (In earlier work, The Dog Project was the first to train dogs, without being bound or sedated, to remain still in a scanner while their brain activity was examined. Check out the video at the end of this article to see how the pups were trained.)
Each of the dogs was tested 32 times for each of the three items, as the scanner recorded their neural activity.
Then, in a behavioral test, each dog was tested with a Y-shaped maze in a room. At one tip of the Y was their owner and at the other a bowl of food. Whenever a dog went to its owner first, it received praise. The dogs were repeatedly let loose in this maze, their choices recorded.
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The bottom line of all of these tests would likely be encouraging to dog owners.
"Out of the 13 dogs that completed the study," said Berns, "we found that most of them either preferred praise from their owners over food, or they appeared to like both equally."
"Only two of the dogs were real chowhounds," he added, "showing a strong preference for the food."