Another nail in the coffin - of the prosecution case

Explosive- and drug-sniffing dog performance is affected by their handlers' beliefs

UC Davis study finds detection dogs may exhibit the 'Clever Hans' effect

Drug- and explosives-sniffing dog/handler teams' performance 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 post-doctoral 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."

(The article goes on to explain the methodology in detail. The so called 'interest' shown by the dogs at the area the boat was launched is thus shown to be unreliable at best, and probably fraudulent. The 'interest' was almost certainly that of the handler, since Laci was never at the dock area.)