-Submitted by David Drumm (Nal), Guest Blogger
The United States Supreme Court recently issued a unanimous (9-0) decision in Florida v. Harris (2013) that deals with probable cause and drug detection dogs. The Court overturned the Florida Supreme Court ruling (pdf) and held that the police officer had probable cause, based on the dog’s reliability, to search Harris’s truck. The Court also held that: “If the State has produced proof from controlled settings that a dog performs reliably in detecting drugs, and the defendant has not contested that showing, the court should find probable cause.”
When testing a dog’s detection reliability in a “controlled setting,” a key factor would be whether the test is double-blind. That is, neither the dog and the handler know where the drugs are hidden. As is often the case however, it is the handler that designs the test and the handler will cue the dog. Lawrence Myers, a veterinarian and neurophysiologist at Auburn University who is an expert on dogs’ olfactory capabilities, notes the handler “can’t help” but cue the dog and skew the training.
The unconscious cueing of animals is known as the “Clever Hans Effect.” Clever Hans fascinated audiences solving mathematical problems by stomping its front hooves. An investigation determined that the horse was responding to subtle, subconscious cues from its handler to indicate when to start stomping and when to stop.
In a UC Davis study, researchers 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.” Even the best trained nose can be impacted by the handler. Anita M. Oberbauer, chair of the Department of Animal Science and the study’s senior author, said: “Dogs are exceptionally keen at interpreting subtle cues, so handlers need to be cognizant of that to optimize the overall team performance.”
Of course that implies that the handler wants to optimize the overall performance. Police have strong incentives to use a drug detection dog that alerts promiscuously. Asset forfeitures are a powerful incentive for cash-strapped police departments. When an officer’s performance reviews and potential promotion are based, in part, on the number of drug busts and drug seizures made, and the use of a dog prone to false positives is to an officer’s personal advantage.
K-9 teams use many tricks to conceal the dog’s supposed “alerts.” If the scene is being videotaped by a police dash-cam, the officer will stand between the camera and the dog, or take the dog to the front of the suspect vehicle where the dog is out-of-sight. Many police departments has stopped recording K-9 teams because “the dogs don’t alert when the cops say they alert.” Handlers also use excessive verbal encouragement and lavish praise to get the dog to respond.
An investigation of three years of data by the Chicago Tribune found that: “only 44 percent of those alerts by the dogs led to the discovery of drugs or paraphernalia.” When considering Hispanic drivers, the success rate fell to 27 percent. Justice Kagan, writing the opinion of the Court, noted that in such cases, “the dog may have smelled the residual odor of drugs previously in the vehicle or on the driver’s person.” Such an hypothetical claim is a little too convenient and should raise suspicions about its validity. According to J. Kagan, a dog’s alert “establishes a fair probability—all that is required for probable cause—that either drugs or evidence of a drug crime … will be found.”
The Supreme Court is set to decide Florida v. Jardines, a case involving a drug detecting dog that was brought up to the front door of Jandines’s home. The dog sniffed around the front door for a minute or two and the officer claimed that the dog alerted. Based on the dog’s alert, a search warrant was obtained. The Florida Supreme Court determined that the search was illegal because the dog’s inspection of the front door was an illegal search. Keep your fingers crossed.