Study: Dogs can dig through human deception

— -- Man's best friend or food-grubbing flatterer? Dogs are no dummies either way, suggests a study showing how canines respond to deception.

Fido always seems to know which hand hides the treat, even without sniffing, and researchers and pet owners alike have long wondered whether pooches imagine what we are thinking or whether they simply read body language.

"Dogs evolved with humans, and a number of studies have suggested they are particularly sensitive to human cues," says psychologist William Roberts of Canada's Dalhousie University. Sentimental pet owners might even say their dogs know what they are thinking.

To test how well dogs have people figured out, Roberts and colleagues performed three experiments reported in the current Behaviour Process journal. The team recruiting pet owners and tested 16 dogs in a park near London, Ontario.

First, the researchers presented the dogs with two covered buckets, one empty, one loaded with treats. In some trials, the same tester would always signal to the dogs the empty bucket. In other trials, another tester would signal the full bucket.

The dogs started out running to the bucket indicated by testers in both trials, but within five attempts, the dogs figured out a little less than half the time to run to the bucket not indicated by the "deceptive" tester.

Similar tests were done decades ago in chimps, notes psychologist Clive Wynne of the University of Florida-Gainesville, editor of the journal. "One interesting thing is that the dogs are wiping the floor with the chimps in how often, statistically, they figure out the deception," he says.

To see whether the human testers mattered, the team replaced the testers with white or black boxes, placed behind buckets, one empty and one holding hot dog pieces. "It appears that dogs learned rather quickly to approach the (full) box and to avoid the (empty) box," the study says.

"They are just as good at it when no humans are involved," Wynne says. The study suggests, he adds, that "sometimes for your dog, you are just a stimulus machine that provides food" rather than a thinking creature whose intentions need to be read.