Seven years ago, a researcher named Lisa Lit published a study that she now calls "a real career-ender."
On the surface, the study tested the abilities of fourteen certified sniffer dogs to find hidden "targets." In reality, the dogs' human handlers were also under the magnifying glass. They were led to believe there were hidden target scents present, when in fact there were none. Nevertheless, the dogs "alerted" to the scents multiple times — especially in locations where researchers had indicated a scent was likely.
"I think the findings were a little surprising," Lit says. "I don't think the number of incorrect responses was what anybody was really anticipating out of this study."
Police dogs searching for drugs sometimes "alert" for them when they're not there. That raises questions about the influence of the dogs' handlers. As NPR learned, there is now an effort by some in the training community to eliminate the influence of their handlers' suspicions to make dog searches more fair.
Lit's study made headlines in the U.S. and abroad, as it seemed to question the impartiality of police K9 teams. In most states, an alert by a certified drug-sniffing dog gives police the right to search your car; some cops jokingly refer to the dogs as "probable cause on four legs." With this study, that probable cause looked shakier.
