Scent detection dogs and their handlers work as a team and the behavior of both of them influences the outcome. It has long been known that dogs take cues from their human handlers and may mistakenly identify a target scent (a false positive) based on the person’s behavior. They may also search in patterns based on instructions from the handler rather than according to their own inclinations.
A recent study (Human-animal interface: The effects of handler’s stress on the performance of canines in an explosive detection task) in the journal Applied Animal Behaviour Science shows that the handler’s stress level has an impact on the search. Specifically, researchers found that when the people were stressed, the dogs performed better, detecting the explosives more quickly.
In the study, handlers in the Israeli army were presented with two different types of stressors in a random experimental design in which every handler faced the same stressors. One stressor was related to the handling task. Observers, including commanders, were present during a detection session, and as part of the experimental design, they pointed at the handler from a distance and pretended to write down comments during the session. The other stressor was not related to the task. Before those sessions, a handler was told by the commander that the handler would be transferred to another military unit and need to face a military police investigation. Each team also had a control session with no stressors.
Handlers were monitored during their sessions to determine physiological measures of stress. Stressors decreased the handlers’ attention and increased their anxiety levels compared to control sessions.
Dogs found the explosives more quickly when their handlers were stressed, especially by factors unrelated to the task. The dogs also showed more activity in general under this experimental condition. These results support the hypothesis that handlers’ emotional states have an impact on the performance of working dogs.
The researchers propose one possibility for the dogs’ improved performance when their handlers were stressed: Perhaps they were less attentive to the task at hand, allowing the dogs to behave in a less “handler-dependent manner.” They propose that there may be benefits to allowing dogs more control over their own behavior during detection work.