Animal Cognition

, Volume 8, Issue 3, pp 143–150 | Cite as

The role of context specificity in learning: the effects of training context on explosives detection in dogs

Original Article

Abstract

Various experiments revealed that if an animal learns a stimulus–response–reinforcer relationship in one context and is then tested in another context there is usually a lessening of stimulus control, and the same discriminative stimuli that reliably controlled the behavior in the first context will have less effect in the new context. This reduction in performance is known as the “context shift effect.” The effect of changing context on the probability of detecting explosives was investigated in seven highly trained explosives detection dogs (EDDs). In experiment 1 the dogs were trained alternately on path A, which always had five hidden explosives, and on a very similar path B, which never had any explosives. Within a few sessions the dogs showed a significant decrease in search behavior on path B, but not on path A. In experiment 2 the same dogs were trained only on path B with a target density of one explosive hidden every 4th day. The probability of the dogs now detecting the explosive was found to be significantly lower than in experiment 1. In experiment 3 the effect of the low target density as used in experiment 2 was investigated on a new but very similar path C. Both the detection probability for the one explosive every 4th day on the new path and the motivation to search were significantly higher than found in experiment 2. Finally, in experiment 4, an attempt was made to recondition the dogs to search on path B. Although trained for 12 daily sessions with one explosive hidden every session, the dogs failed to regain the normal levels of motivation they had shown on both new paths and on the paths that they knew usually contained explosives. The findings reveal that even a very intensively trained EDD will rapidly learn that a specific stretch of path does not contain explosives. The dog will then be less motivated to search and will miss newly placed targets. This learning is specific to the formerly always-clean path and is to some extent irreversible. However, the dog will search and detect normally on new paths even if they are very similar to the always-clean path. The data are discussed in terms of variables affecting renewal. The results suggest that following training designed to make a behavior “context independent,” any extinction training will not generalize beyond that specific context used during the extinction training. In addition, if the behavior is extinguished in a specific context, it will be very difficult to restore that behavior in that context. These conclusions should be considered by anyone attempting to extinguish well-established trans-context behaviors.

Keywords

Dog Olfaction Explosive Context shift effect Extinction 

Notes

Acknowledgements

We gratefully acknowledge Dr. A. Terkel and Ms. N. Paz for help in preparation and editing of the manuscript, and Ms. I. Gunther and Ms. N. Gazit for help with data analysis. We also thank the dog trainers, handlers, and dogs themselves for participating in this study.

References

  1. Balsam PD, Tomie A (1985) Context and learning. Erlbaum, Hillsdale, N.J.Google Scholar
  2. Blair CAJ, Blundell P, Galtress T, Hall G, Killcross S (2003) Discrimination between outcomes in instrumental learning: effects of preexposure to the reinforcers. Q J Exp Psychol B 56:253–365CrossRefPubMedGoogle Scholar
  3. Bouton ME, Bolles RC (1979) Role of conditioned contextual stimuli in reinstatement of extinguished fear. J Exp Psychol Anim Behav Process 5:368–378CrossRefPubMedGoogle Scholar
  4. Bouton ME, Ricker ST (1994) Renewal of extinguished responding in a second context. Anim Learn Behav 22:317–324Google Scholar
  5. Gunther LM, Denniston JC, Miller RR (1998) Conductivity exposure treatment in multiple contexts can prevent relapse. Behav Res Ther 36:75–91CrossRefPubMedGoogle Scholar
  6. Hilliard S (2003) Principles of animal learning. In: Mclean IG (ed) Mine detection dogs: training, operations and odour detection. Geneva International Centre for Humanitarian Demining, Geneva, pp 23–42Google Scholar
  7. Mondragon E, Hall G (2002) Analysis of the perceptual learning effect in flavour aversion learning: Evidence for stimulus differentiation. Q J Exp Psychol B 55:153–169CrossRefPubMedGoogle Scholar
  8. Pear G, Martin J (1990) Behavior modification: what it is and how to do it. Pearson Higher Education, Upper Saddle River, N.J.Google Scholar
  9. Rodriquez BI, Craske MG, Mineka S, Hladek D (1999) Context-specificity of relapse: effects of therapist and environmental context on return of fear. Behav Res Ther 37:845–862CrossRefPubMedGoogle Scholar
  10. Thomas DR (1985) Contextual stimulus control of operant responding in pigeons. In: Balsam PD, Tomie A (eds) Context and learning. Erlbaum, Hillsdale, N.J., pp 295–321Google Scholar
  11. Thomas DR, Empedocles S, Morrison SK, Bing MN (1993) Context specificity of operant discriminative performance in pigeons II. Necessary and sufficient conditions. J Exp Anal Behav 60:313–329Google Scholar
  12. Thomas BL, Larsen N, Ayres JJB (2003) Role of context similarity in ABA, ABC, and AAB renewal paradigms: implications for theories of renewal and for treating human phobias. Learn Motiv 34:410–436CrossRefGoogle Scholar
  13. Turner TN, Stafford SG, McHugh MB, Surovik L, Delgross D, Fad O (1991) The effects of context shift in killer whales (Orcinus Orca). In: Allen S (ed) Proceedings of the International Marine Animal Trainers Association 1991 Annual Conference, 4–8 November 1991Google Scholar
  14. Winer BJ (1962) Statistical procedures in experimental design. McGraw-Hill, New YorkGoogle Scholar
  15. Zhou Y, Riccio DC (1996) Manipulation of components of context: the context shift effect and forgetting of stimulus attributes. Learn Motiv 27:400–407CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.Department of Zoology, George S. Wise Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael

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