New York City recently introduced a team of sniffing dogs specially trained to patrol the subway. The cops won't say whether these dogs are trained to detect drugs, explosives, or both.
This story made me wonder: How do police departments prevent unethical K-9 cops from secretly teaching their animals to sniff on command? Obviously, they're trained to sniff only when they smell contraband, but it seems like it would be pretty easy to override that default, deliberately or by accident.
I understand that police dogs often live with their handlers. So, cops usually have plenty of time alone to teach their dogs new tricks. Could an officer train a dog to sniff on command using covert signals, such as eye movements or seemingly natural gestures? It would be very convenient for a bullying cop to teach his dog to sniff on command. In the wrong hands, a subverted sniffer could be a furry license to search anyone.
For that matter, how do the K-9 police guard against the "Clever Hans" phenomenon? In the early 20th century, a horse called Clever Hans became world famous for his apparent ability to do arithmetic and other astonishing feats. Upon further investigation, it turned out that the horse was learning to respond to subtle, involuntary changes in posture. People were asking him questions to which they already knew the answers. Hans would tap out the "solutions" to arithmetic problems with his hoof. It turns out people naturally shifted their heads when he got to the right number.
I wonder whether something similar might go on between police officers and their dogs. Officers develop a close bond with their dogs. Even civilian dog owners report that their animals can be almost eerily attuned into their body language. Do the K-9 trainers use safeguards to make sure the officer's feelings don't subtly affect the dog's behavior? For example, suppose that a subway officer strongly suspects that someone on the subway is up to no good. Could subtle cues from the officer make the dog more likely to sniff a person?
I wonder how you would go about closing these security holes. You could probably detect the Clever Hans phenomenon by designing drills where the officer's beliefs are the independent variable. If the dog is more likely to sniff at packages when the officer thinks there's contraband in it, there's a problem. If it's an honest cop, animal behaviorists could probably work with the officer to control whatever ticks are setting the dog off. I have no idea how to make sure that cops aren't deliberately teaching their dogs to respond to illicit commands, though.
I don't know whether a dog sniffing at a person constitutes probable cause for a search. I hope not. It seems to me that a sniffing dog could easily be a crooked cop's best friend.