Handlers’ beliefs influence drug-sniffing dogs’ performance

Handlers’ beliefs influence drug-sniffing dogs’ performance

The accuracy of drug- and explosives-sniffing dogs is affected by human
handlers’ beliefs, possibly in response to subtle, unintentional cues, UC
Davis researchers have found.

The study, published in the January issue of the journal Animal Cognition,
found that detection-dog 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," says Lisa Lit, a postdoctoral fellow in the Department of Neurology and
the study’s lead author. "There are cognitive factors affecting the
interaction between a dog and a handler that can impact the dog’s
performance."

And it turns out, these factors can be even more important than the
sensitivity of a dog’s sniffer.

"Dogs are exceptionally keen at interpreting subtle cues, so handlers need
to be cognizant of that to optimize the overall team performance," adds
Anita M. Oberbauer, UC Davis chair of the Department of Animal Science and
the study’s senior author.

To evaluate the effects of handler beliefs and expectations on detection-dog
performance, the researchers recruited 18 handler-detection dog teams from
law-enforcement agencies. All of the teams were certified by an agency for
either drug detection, explosives detection or both drug.

The dogs all were trained to either alert passively at the location of a
scent by sitting or laying down, alert actively by barking or by doing both.
The teams included 14 male dogs and four female dogs, including Labrador
retrievers, Belgian Malinois, German Shepherd dogs and Dutch Shepherd dogs.
The dogs’ level of experience ranged from two to seven years and their human
partners had as many as 18 years of dog-handling experience.

A church was selected as the location for the study, since it was unlikely
to have contained either explosives or drugs in the past. It was also a
place where neither the dogs nor the handlers had been before. The
researchers created four separate rooms for the dogs to examine or "clear."

The handlers were told that there might be up to three of their target
scents in each room, and that there would be a piece of red construction
paper in two of the rooms that identified the location of the target scent.
However, there were no target scents ‹ explosives or drugs ‹ placed in any
of the rooms.

Each room represented a different experimental condition or scenario:

In room #1 the experimenter did nothing.
In room #2 she taped a piece of red construction paper to a cabinet.
In room #3 she placed decoy scents, two sausages and two tennis balls hidden
together out of view.
In room #4 she placed a piece of red construction paper at the location of
hidden decoy scents, two sausages and two tennis balls.
The dog-handler teams conducted two separate, five-minute searches of each
room. When handlers believed their dogs had indicated a target scent, an
observer recorded the location indicated by handlers. All of the teams
searched the rooms in a different order.

Although there should have been no alerts in any of the rooms, there were
alerts in all of them. And more alerts occurred at the target locations
indicated by human suggestion (red construction paper) than at locations of
increased dog interest (sausages and tennis balls).

In the early 20th century in Germany, a horse named Clever Hans was believed
to be capable of counting and other tasks. It was later determined that
Clever Hans was actually responding to the minute, postural and facial cues
of his trainer and other observers. Similarly, detection dogs may be alerted
to subtle and unintentional human cues that direct dog responses, including
pointing, nodding head-turning and gazing.

Although Lit is careful to note that her findings do not mitigate the
abilities of handlers and their dog teams to perform successfully, she
believes they are significant. It is her hope that the study can be
replicated and expanded to further assess hidden cues handlers may be giving
their dogs. "It might be the case that everyone is doing the same types of
things so that [they could be addressed] directly," she says.

Read more:
http://www.sfgate.com/cgi-bin/blogs/pets/detail?entry_id=82270#ixzz1D35ciN1f

Feb. 2, 2011 from SF Gate