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Assessing the Assessors

Study examines accuracy of rubber hand and life-size doll in predicting canine aggression toward people.

Study examines accuracy of rubber hand and life-size doll in predicting canine aggression toward people.

The Assess-a-Hand developed by behavior expert Sue Sternberg has become a standard tool for gauging a dog’s potential to bite. Testing responses to new objects or phenomena can provide invaluable information on how an animal handles uncertainty, indicating whether standard owner behaviors such as food bowl removal might turn a seemingly sweet and docile beagle into a font of murderous, snarling rage. Tools like the Assess-a-Hand are also helpful because they allow trainers to check for fear-biting and other responses without risking their own limbs in the process.

But such tools have been controversial—and not just because each tester handles the assessment tool differently. While rubber hands and human-shaped dolls bear resemblances to the real things, there are differences: No matter how skilled the tester, a rubber hand or doll doesn’t move or smell the same way a real hand or child does. Some have been critical of these devices for just these reasons, suggesting that dogs’ responses to them may not provide an accurate indication of how the animals react to real-world situations.

A study published in the Journal of the American Animal Hospital Association (Vol. 40, No. 1), however, indicates that these tools do in fact provide strong indicators for real-world dog behavior. “The Use of Novel Stimuli as Indicators of Aggressive Behavior in Dogs” (by Tracy Knoll, Katharine Houpt, and Hollis Erb) examined how 100 dogs with known behavior histories responded to two different tests: the Assess-a-Hand test and a test conducted with a life-size doll shaped like a female child.

In the first exercise, the artificial hand was used to pet the dog’s head, stomach, and rump; the hand was then made to feel the dog’s mouth, reach for the dog’s collar, and fondle the ears. Testers also used the hand to remove food from a bowl that had been given to the dog. In the second test, a doll was manipulated by a tester to move rapidly toward the dog with its arms extended; the doll was made to pet the dog’s head, neck, and back and to reach into the mouth. The doll was dropped in front of the dog, picked up, made to corner the dog, and then moved away quickly to see if the dog would chase it.

The researchers found that the rubber hand was fairly accurate in diagnosing fearful aggression in dogs who had shown fear-related aggressive tendencies in the past. Of the dogs who reacted to the hand with fear-related aggression, 89 percent had displayed behaviors in the past that indicated the same problem; in other words, results of the Assess-A-Hand test were likely to resemble past behaviors in the animals evaluated.

Of the dogs who reacted aggressively to the doll, 65 percent had actually bitten or snapped at a child and 24 percent had barked or growled at a child. There were some false positives, the researchers noted—dogs who reacted aggressively to stimuli but had no history of aggression towards children—and there were a few false negatives as well. Some dogs who had bitten children were not aggressive towards the doll. “[I]n other words, these dogs in some way discriminated between the doll and real children,” the researchers wrote.

“In a shelter situation, if these tests are used as a part of determining adoptability, then dogs will be missed that are aggressive, and some dogs may be deemed unadoptable that would otherwise be adoptable,” the researchers wrote. Given the largely positive correlations between reactions to the stimuli and history of aggression, however, the researchers noted that “the doll and the hand give some information as to the possibility of a dog having a dominance aggression or fearful aggression problem. Any aggression shown to the hand or doll should be looked at with concern. ... These tests have shown potential as one component of temperament testing in dogs that should be further evaluated.”


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