Dogs may have a keen sense of smell, but their powers of observation could be just as highly developed -- causing specially trained canines to poke their noses in all the wrong places because of unintentional cues from their handlers.
With heightened concern over terrorists, drug smugglers and others with nefarious intentions, researchers at the University of California, Davis, say scent-detection canines could be led astray by mistaken assumptions from humans.
To err is human, after all.
"It isn't about people doing things incorrectly. It has more to do with the relationships between dogs and humans," said Lisa Lit, the study's lead author and a postdoctoral fellow at the UC Davis Department of Neurology.
"When it comes to dogs, it's not just about how good their noses are," she said. It's also about the biases and beliefs of their handlers.
As part of Lit's study, published last month in the journal Animal Cognition, 18 dog-handler teams took part in an experiment requiring the canines to sniff out a church. Handlers were falsely told that researchers had planted gunpowder and marijuana in the church. As part of the ruse, the handlers were shown sealed bags of the substances, but none was actually planted in the building.
Still, the dogs were apparently led to targets the handlers mistakenly believed had the scent of contraband.
Steve Brewer, a dog trainer and former Sacramento, Calif., police officer with the canine unit, said the study's findings weren't a surprise.
"Dogs do pick up on the handler's body language," he said.
The most skilled dog handlers know how to keep their biases and body language from influencing their canine, said Brewer, who operates Law Dogs in Colfax.
Other dog trainers called the study a setup.
"This study is worthless. These guys couldn't possibly win," said Mark Rispoli, a member of the executive board of the California Narcotic and Explosive Canine Association and the group's legal counsel.
"The bottom line is this: If a dog is trained correctly and maintained correctly, there shouldn't be any influence by the handler because it's the dog doing the task, not the handler," Rispoli said. "What the dog does is search. The handler is a search manager."
Rispoli argued that the research could be potentially damaging and cast doubt on the work performed by dogs and their handlers.
Since the terrorist attacks of Sept. 11, 2001, there has been heightened concern about bombs infiltrating airports and the country's borders. Bomb-sniffing dogs have been deployed with greater visibility at luggage carousels and security checkpoints. "This is important work. This isn't about circus horses," Rispoli said.
Rispoli was referring to a horse named Clever Hans, who drew crowds a century ago in Germany for his amazing intellectual prowess, including the seeming ability to count and add. As it turned out, the horse was responding to cues from his trainer and the crowd.
The "Clever Hans effect" has become a widely accepted example, according to the UC Davis study, of an animal's ability to respond to unintentional cues by those around them.
Lit acknowledged the criticism coming from dog handlers. "People have been surprised by the findings. All the handlers are professional. They want to go out and do their jobs."
UC Davis researchers also are quick to point out the limitations of their experiment.
"Our study suggests a need for further study," said Lit, who has had experience as a handler.
Other experiments should be videotaped, she said, to better analyze the human behaviors that dogs perceive as cues.
(E-mail The Bee's Bobby Caina Calvan at bcalvan(at)sacbee.com.)
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