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Open Access Publications from the University of California


The International Journal of Comparative Psychology is sponsored by the International Society for Comparative Psychology. It is a peer-reviewed open-access digital journal that publishes studies on the evolution and development of behavior in all animal species. It accepts research articles and reviews, letters and audiovisual submissions.

Volume 16, Issue 4, 2003


The Steel Helmet Project: Canine Olfactory Detection of Low Concentrations of a Surrogate Chemical Warfare Agent

The Steel Helmet project was meant to assess the feasibility of the chemical warfare agent (CWA) detector dog concept. A relatively benign organophosphate pesticide called dichlorvos was used as a surrogate for CWAs. Using conventional training techniques, U.S. Department of Defense military working dogs were taught to discriminate scent boxes containing dichlorvos from “vehicle” scent boxes. Experiment 1 appeared to show that two out of three subjects were capable of criterion accuracy (0.95 or better) at the lowest test concentrations of dichlorvos— 3 and 1 parts per billion by volume (ppbv). An additional manipulation showed that, when differential contamination of the scent boxes in Experiment 1 was accounted for, all three subjects fell short of criterion accuracy when tested at 1 ppbv. The canine dichlorvos detection "threshold" was therefore estimated at equal to or less than 3 ppbv, but not so low as 1 ppbv. Experiment 2 demonstrated that detection responding was specifically controlled by dichlorvos, rather than concomitant odors, and that the subjects were not merely reacting to the novelty or salience of dichlorvos vapor. The implications of these results for the feasibility of the CWA detector dog concept are discussed in terms of safe canine CWA exposure levels.

A Species Difference in Visuospatial Memory: A Failure of Memory for What, Where, or What is Where?

Four experiments were conducted to determine why rhesus monkeys (Macaca mulatta) perform so poorly on a visuospatial memory test modeled after a popular children’s game (Concentration). In these studies, four different memory tasks were administered to ascertain whether monkeys show limitations in visual memory (memory for which images had been seen), limitations in spatial memory (limitations of what locations had been visited), or limitations in the coordination of these two modalities (memory for what images are located where). The data indicate that the monkeys could remember visual information when there were no spatial demands. The monkeys could also remember spatial information when there were no visual-memory demands, although performance on this spatial-memory task was not as accurate as had been predicted. However, when visual and spatial memories had to be coordinated–memory for what was where–performance was no better than chance. Hypotheses were discussed for why the monkeys, but not human participants, struggle to coordinate visual and spatial memory. Perhaps this represents and area where humans use verbal working memory—a mnemonic strategy that is presumably unavailable to nonhuman primates—to facilitate the maintenance and cross-referencing of visual and spatial information.

Full Body Restraint and Rapid Stimulus Exposure as a Treatment for Dogs With Defensive Aggressive Behavior: Three Case Studies

We evaluated the effect of full body restraint and rapid stimulus exposure (response prevention-flooding) on three Great Dane dogs, Canis familiaris, exhibiting high levels of aggression toward strangers or other dogs. We immobilized each dog in a restraint box by pouring grain in the box up to the level of the dog’s neck. Each dog was rapidly subjected to increasing intensity of the appropriate eliciting stimulus (adult, child, or dog) and responses were rated using a standardized numerical rating system. The dogs’ aggressive behavior diminished rapidly during restraint, and resulted in calm behavior during the highest stimulus intensity. Owners reported decreases in aggressive behavior for several months to years following the restraint sessions. Rapid stimulus exposure, when accompanied by complete response prevention, seems to result in large and long-lasting decrements in aggressive responses.

Does Changing Levels of Stress Affect the Characteristics of Grooming Behavior in Rats?

Twenty seven experimentally naïve adult female rats were exposed to a novel arena with shelters for a period of 15 min. Various measures of their pelage-cleaning behavior were analyzed. Bouts of grooming were shown to increase in duration and complexity and decrease in their rostral content over the span of the measurement period. Simultaneously, decrease in risk-assessment activity, as measured by the stretched attend posture, was noted in association with consecutive bouts. The effect on risk assessment appears to demonstrate that the aforementioned changes in grooming bout parameters resulted from a decrease in the level of stress. Differences in the characteristics of the early and the late grooming bouts suggest that bout initiation and bout continuation are affected by two relatively independent mechanisms involved in the shaping of pelage-cleaning behavior.