UC Davis: “Explosive- and drug-sniffing dogs’ performance is affected by their handlers’ beliefs”

Explosive- and drug-sniffing dogs’ performance is affected by their handlers’ beliefs / UC Davis study finds detection dogs may exhibit the “Clever Hans” effect from the UC Davis Health System (Feb. 1, 2011):

The performance of drug- and explosives-sniffing dog/handler teams is affected by human handlers’ beliefs, possibly in response to subtle, unintentional handler cues, a study by researchers at UC Davis has found.

The study, published in the January issue of the journal Animal Cognition, found that detection-dog/handler teams erroneously “alerted,” or identified a scent, when there was no scent present more than 200 times — particularly when the handler believed that there was scent present.

“It isn’t just about how sensitive a dog’s nose is or how well-trained a dog is. There are cognitive factors affecting the interaction between a dog and a handler that can impact the dog’s performance,” said Lisa Lit, a postdoctoral fellow in the Department of Neurology and the study’s lead author.

“These might be as important — or even more important — than the sensitivity of a dog’s nose.

So, is Illinois v. Caballes based on a wrong premises such that it should be overruled?

See Drug WarRant, which gets a hat tip for this post. Update: Caballes talks of the “well trained dog,” but cases have largely ignored that concept with a “close enough for government work” mantra. I don’t think this study even gives “legs” to that concept since it means nothing in the case. Can the defense bar give it meaning?

Another update: This is an article cited inside the Davis article brought to my attention by a reader in Wisconsin: Handler beliefs affect scent detection dog outcomes by Lisa Lit, Julie B. Schweitzer, Anita M. Oberbauer in Animal Cognition published January 12, 2011. I didn’t check on it; he did. Good catch.