Dogs: glass half-full or half-empty creatures?

We've all taken quizzes that purport to tell us whether we're shiny happy people or down-in-the-mouth Negative Nellys. But what about our dogs? Optimism and pessimism may carry over the human-pet barrier. Researchers in the United Kingdom have begun exploring a connection between separation-related anxiety and behaviors and dogs' emotional states.

Mike Mendl and the rest of the animal welfare and behavior research group at Bristol University's School of Clinical Veterinary Science turned to human psychology for their starting point: People's behavior is sometimes tied to their cognitive bias toward optimism or pessimism. In Mendl's study, dogs at two animal shelters were trained to notice that when bowls were placed in one corner of the room, they'd be full of food; in another corner of the room, bowls would be empty. Then researchers placed bowls in different locations between the two extremes.

"Dogs that ran fast to these ambiguous locations, as if expecting the positive food reward, were classed as making relatively 'optimistic' decisions," Mendl says. These dogs also were those that had exhibited fewer separation-anxiety symptoms when left alone for short periods of time.

"Our study suggests that dogs that toilet, bark, and destroy objects in the home [when left alone] appear to make more pessimistic judgments generally," Mendl says.

The Royal Society for the Prevention of Cruelty to Animals (RSPCA) funded the research. The RSPCA's deputy head of companion animals, Dr. Samantha Gaines, says she hopes that the research will encourage owners to seek treatment for dogs before relinquishing them.

The findings were published in Current Biology on the website cell.com Oct. 12.