DRUID HILLS, Ga., Aug. 16 (UPI) -- In an experiment designed to illuminate the relationship between humans and dogs -- whether it's defined by a true bond or a love of food -- researchers found most dogs anticipate the praise of their owner as much or more than a food reward.
"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," Gregory Berns, a neuroscientist at Emory University, said in a news release. "Another, more current, view of their behavior is that dogs value human contact in and of itself."
In the early 1900s, psychologist Ivan Pavlov trained dogs to associated food with a stimulus, like a bell. Eventually, Pavlov was able to make dogs salivate using only the stimulus.
But the latest research, detailed in the journal Social Cognitive and Affective Neuroscience, suggests dogs aren't so single-minded.
Berns and his colleagues began their experiment by training dogs to associated three objects with three different rewards: a pink toy truck with food; a blue toy knight with verbal praise; and a hairbrush with the absence of a reward.
Over the course of 32 trials, the 13 participant dogs were presented with the three objects. The dogs' neural responses to each stimulus were measured using an fMRI machine.
All dogs preferred a reward to none at all. Four dogs showed a particularly strong response to the blue toy knight, while nine dogs responded equally to the two types of reward. Only two dogs were consistently more excited about the pink toy truck and the food reward.
In a second experiment, researchers allowed dogs to follow one of two simple maze paths: one leading to their owner, the other to a bowl of food. Owners sat with their backs turned and praised their dog when he or she arrived.
"We found that the caudate response of each dog in the first experiment correlated with their choices in the second experiment," Berns said. "Dogs are individuals and their neurological profiles fit the behavioral choices they make."
"Most of the dogs alternated between food and owner, but the dogs with the strongest neural response to praise chose to go to their owners 80 to 90 percent of the time," Berns continued. "It shows the importance of social reward and praise to dogs. It may be analogous to how we humans feel when someone praises us."