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Detection dogs sniffing for drugs or bombs are affected by their handlers’ reactions to stimuli, a new study at the University of California has revealed.
Eighteen professional dog handlers and their hounds were asked to complete a set of brief searches. Of the eighteen, thirteen worked in drug detection, three in sniffing out bombs, and two in both.
The searches took place in rooms in a church, with five minutes allocated to each of the different search areas. Before the searches began, the handlers were told that several of the areas might hold up to three target scents and that in two situations those scents would be flagged by red paper.
Unbeknownst to the handlers, though, was that two of the targets held decoy scents in the form of hidden sausages to push the dogs’ interest in a false location. In addition, not one of the search areas actually held the scents of drugs or explosives. Therefore, any “detections” made by the teams had to be false. Recorders, who were blind to the study, marked where handlers indicated that their dogs had raised alerts.
The findings, published in the journal Animal Cognition, show that of 144 searches, only 21 had no alerts. In total, the teams raised 225 alerts, all of which were false. While the sheer number of false alerts may strike some as interesting, the locations of these alerts was what researchers were most fascinated by.
When handlers saw pieces of red paper, which supposedly were what marked scents, they were much more likely to report that their dog had signaled. In the two rooms that contained red paper but no sausages, 32 of a possible 36 alerts were reported. In the two rooms where both pieces of red paper and sausages were hidden the figure was 30, a not all too different figure. The number of alerts in search areas where only sausages were present, however, was 17.
While the dogs were distracted by the stimuli aimed toward them, it appears that the stimuli that were aimed at the handlers had a greater affect, with the handlers’ reactions rubbing off on to the dogs. Interestingly, in almost every case the handlers could not help but be distracted by the stimuli.
In the real world, this could mean false positives come up much more than they should. Not only would this inconvenience those innocent, but it would also distract teams from finding guilty parties. Racial profiling could also play a role here in finding false positives.
If a handler thinks someone is carrying drugs or a bomb, the dog is much more likely to signal that that person is carrying such goods, even if the person is not. While it is unclear how handlers will be able to get around this problem, hopefully the news can spark a change in the system.