Handler beliefs affect scent detection dog outcomes - PMC
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Anim Cogn<br>. 2011 Jan 12;14(3):387–394. doi: 10.1007/s10071-010-0373-2
Handler beliefs affect scent detection dog outcomes
Lisa Lit<br>Lisa Lit
1Department of Neurology, University of California at Davis, Sacramento, CA 95817 USA
4M.I.N.D. Institute, University of California at Davis, 2805 50th Street, Room 2415, Sacramento, CA 95817 USA
Find articles by Lisa Lit
1,4,✉, Julie B Schweitzer<br>Julie B Schweitzer
2Department of Psychiatry and Behavioral Science, University of California at Davis, Sacramento, CA 95817 USA
Find articles by Julie B Schweitzer
2, Anita M Oberbauer<br>Anita M Oberbauer
3Department of Animal Science, University of California at Davis, Davis, CA 95616 USA
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1Department of Neurology, University of California at Davis, Sacramento, CA 95817 USA
2Department of Psychiatry and Behavioral Science, University of California at Davis, Sacramento, CA 95817 USA
3Department of Animal Science, University of California at Davis, Davis, CA 95616 USA
4M.I.N.D. Institute, University of California at Davis, 2805 50th Street, Room 2415, Sacramento, CA 95817 USA
✉Corresponding author.
Received 2010 Mar 30; Revised 2010 Dec 13; Accepted 2010 Dec 14; Issue date 2011.
© The Author(s) 2011
This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
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PMCID: PMC3078300 PMID: 21225441
Abstract
Our aim was to evaluate how human beliefs affect working dog outcomes in an applied environment. We asked whether beliefs of scent detection dog handlers affect team performance and evaluated relative importance of human versus dog influences on handlers’ beliefs. Eighteen drug and/or explosive detection dog/handler teams each completed two sets of four brief search scenarios (conditions). Handlers were falsely told that two conditions contained a paper marking scent location (human influence). Two conditions contained decoy scents (food/toy) to encourage dog interest in a false location (dog influence). Conditions were (1) control; (2) paper marker; (3) decoy scent; and (4) paper marker at decoy scent. No conditions contained drug or explosive scent; any alerting response was incorrect. A repeated measures analysis of variance was used with search condition as the independent variable and number of alerts as the dependent variable. Additional nonparametric tests compared human and dog influence. There were 225 incorrect responses, with no differences in mean responses across conditions. Response patterns differed by condition. There were more correct (no alert responses) searches in conditions without markers. Within marked conditions, handlers reported that dogs alerted more at marked locations than other locations. Handlers’ beliefs that scent was present potentiated handler identification of detection dog alerts. Human more than dog influences affected alert locations. This confirms that handler beliefs affect outcomes of scent detection dog deployments.
Keywords: Dog, Canine, Scent detection, Social cognition, Interspecies communication
Introduction
In the early twentieth century, a horse named Clever Hans was believed to be capable of counting and other mental tasks. The psychologist Oskar Pfungst confirmed that Clever Hans was in fact recognizing and responding to minute, unintentional postural and facial cues of his trainer or individuals in the crowd (Pfungst 1911). The “Clever Hans” effect has become a widely accepted example not only of the involuntary nature of cues provided by onlookers in possession of knowledge unavailable to others, but of the ability of animals to recognize and respond to subtle cues provided by those around them. However, an additional important consideration was the willingness of onlookers to assign a biased interpretation of what they saw according to their expectations.
Experimental paradigms for investigation of animal behaviors are designed to minimize or eliminate confounds arising from the Clever Hans effect. Because the abilities of domestic dogs...