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Gazit, I., Goldblatt, A., & Terkel, J. (2005). The role of context specificity in learning: the effects of training context on explosives detection in dogs. Anim. Cogn., 8(3), 143–150.
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.
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Osthaus, B., Lea, S. E. G., & Slater, A. M. (2005). Dogs (Canis lupus familiaris) fail to show understanding of means-end connections in a string-pulling task. Anim. Cogn., 8(1), 37–47.
Abstract: Domestic dogs (Canis lupus familiaris) were tested in four experiments for their understanding of means-end connections. In each of the experiments, the dogs attempted to retrieve a food treat that could be seen behind a barrier and which was connected, via string, to a within-reach wooden block. In the experiments, either one or two strings were present, but the treat was attached only to one string. Successful retrieval of the treat required the animals to pull the appropriate string (either by pawing or by grasping the wooden block in their jaws) until the treat emerged from under the barrier. The results showed that the dogs were successful if the treat was in a perpendicular line to the barrier, i.e. straight ahead, but not when the string was at an angle: in the latter condition, the typical response was a proximity error in that the dogs pawed or mouthed at a location closest in line to the treat. When two strings that crossed were present, the dogs tended to pull on the wrong string. The combined results from the experiments show that, although dogs can learn to pull on a string to obtain food, they do not spontaneously understand means-end connections involving strings.
Keywords: Animals; *Association Learning; *Cognition; Dogs/*psychology; *Problem Solving
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Gácsi, M., Miklósi, Á., Varga, O., Topál, J., & Csányi, V. (2004). Are readers of our face readers of our minds? Dogs (Canis familiaris) show situation-dependent recognition of human's attention. Anim. Cogn., 7(3), 144–153.
Abstract: The ability of animals to use behavioral/facial cues in detection of human attention has been widely investigated. In this test series we studied the ability of dogs to recognize human attention in different experimental situations (ball-fetching game, fetching objects on command, begging from humans). The attentional state of the humans was varied along two variables: (1) facing versus not facing the dog; (2) visible versus non-visible eyes. In the first set of experiments (fetching) the owners were told to take up different body positions (facing or not facing the dog) and to either cover or not cover their eyes with a blindfold. In the second set of experiments (begging) dogs had to choose between two eating humans based on either the visibility of the eyes or direction of the face. Our results show that the efficiency of dogs to discriminate between “attentive” and “inattentive” humans depended on the context of the test, but they could rely on the orientation of the body, the orientation of the head and the visibility of the eyes. With the exception of the fetching-game situation, they brought the object to the front of the human (even if he/she turned his/her back towards the dog), and preferentially begged from the facing (or seeing) human. There were also indications that dogs were sensitive to the visibility of the eyes because they showed increased hesitative behavior when approaching a blindfolded owner, and they also preferred to beg from the person with visible eyes. We conclude that dogs are able to rely on the same set of human facial cues for detection of attention, which form the behavioral basis of understanding attention in humans. Showing the ability of recognizing human attention across different situations dogs proved to be more flexible than chimpanzees investigated in similar circumstances.
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Hare, J. F., Sealy, S. G., Underwood, T. J., Ellison, K. S., & Stewart, R. L. M. (2003). Evidence of self-referent phenotype matching revisited: airing out the armpit effect. Anim. Cogn., 6(1), 65–68.
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Fiset, S., Beaulieu, C., & Landry, F. (2003). Duration of dogs' (Canis familiaris) working memory in search for disappearing objects. Anim. Cogn., 6(1), 1–10.
Abstract: Two experiments explored the duration of dogs' working memory in an object permanence task: a delay was introduced between the disappearance of a moving object behind a box and the beginning of the search by the animal. In experiment 1, the dogs were tested with retention intervals of 0, 10, 30, and 60 s. Results revealed that the dogs' accuracy declined as a function of the length of the retention interval but remained above chance for each retention interval. In experiment 2, with new subjects, longer retention intervals (0, 30, 60, 120, and 240 s) were presented to the dogs. Results replicated findings from experiment 1 and revealed that the dogs' accuracy remained higher than chance level with delays up to 240 s. In both experiments, the analysis of errors also showed that the dogs searched as a function of the proximity of the target box and were not subject to intertrial proactive interference. In the discussion, we explore different alternatives to explain why dogs' search behaviour for hidden objects decreased as a function of the retention intervals.
Keywords: Animals; Dogs/*psychology; *Exploratory Behavior; Female; Male; *Memory; Visual Perception
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West, R. E., & Young, R. J. (2002). Do domestic dogs show any evidence of being able to count? Anim. Cogn., 5(3), 183–186.
Abstract: Numerical competence has been demonstrated in a wide range of animal species. The level of numerical abilities shown ranges from simple relative numerousness judgements to true counting. In this study we used the preferential looking technique to test whether 11 pet dogs could count. The dogs were presented with three simple calculations: “1+1=2”; “1+1=1”; and “1+1=3”. These calculations were performed by presenting the dogs with treats that were placed behind a screen that allowed manipulation of the outcome of the calculation. When the dogs expected the outcome they spent the same amount of time looking at the result of the calculation as they did on the initial presentation. However, when the result was unexpected dogs spent significantly longer looking at the outcome of the calculation. The results suggest that the dogs were anticipating the outcome of the calculations they observed, thus suggesting that dogs may have a rudimentary ability to count.
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Prato-Previde, E., Marshall-Pescini, S., & Valsecchi, P. (2008). Is your choice my choice` The owners effect on pet dogs? ( Canis lupus familiaris ) performance in a food choice task. Anim. Cogn., 11(1), 167–174.
Abstract: Abstract This study investigates the influence of owners on their dogs performance in a food choice task using either different or equal quantities of food. Fifty-four pet dogs were tested in three different conditions. In Condition 1 we evaluated their ability to choose between a large and small amount of food (quantity discrimination task). In Condition 2 dogs were again presented with a choice between the large and small food quantity, but only after having witnessed their owner favouring the small quantity. In Condition 3 dogs were given a choice between two equally small quantities of food having witnessed their owner favouring either one or the other. A strong effect of the owner on the dogs`` performance was observed. In Condition 1 dogs as a group chose significantly more often the large food quantity, thus showing their ability to solve the quantity discrimination task. After observing their owner expressing a preference for the small food quantity they chose the large quantity of food significantly less than in the independent choice situation. The tendency to conform to the owner`s choice was higher when the dogs had to choose between equally small quantities of food (Condition 3) rather than between a large and a small one (Condition 2). These results provide evidence that dogs can be influenced by their owners even when their indications are clearly in contrast with direct perceptual information, thus leading dogs to ultimately make counterproductive choices.
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Adachi, I., Kuwahata, H., & Fujita, K. (2007). Dogs recall their owner's face upon hearing the owner's voice. Anim. Cogn., 10(1), 17–21.
Abstract: Abstract We tested whether dogs have a cross-modal representation of human individuals. We presented domestic dogs with a photo of either the owner's or a stranger's face on the LCD monitor after playing back a voice of one of those persons. A voice and a face matched in half of the trials (Congruent condition) and mismatched in the other half (Incongruent condition). If our subjects activate visual images of the voice, their expectation would be contradicted in Incongruent condition. It would result in the subjects` longer looking times in Incongruent condition than in Congruent condition. Our subject dogs looked longer at the visual stimulus in Incongruent condition than in Congruent condition. This suggests that dogs actively generate their internal representation of the owner's face when they hear the owner calling them. This is the first demonstration that nonhuman animals do not merely associate auditory and visual stimuli but also actively generate a visual image from auditory information. Furthermore, our subject also looked at the visual stimulus longer in Incongruent condition in which the owner's face followed an unfamiliar person's voice than in Congruent condition in which the owner's face followed the owner's voice. Generating a particular visual image in response to an unfamiliar voice should be difficult, and any expected images from the voice ought to be more obscure or less well defined than that of the owners. However, our subjects looked longer at the owner's face in Incongruent condition than in Congruent condition. This may indicate that dogs may have predicted that it should not be the owner when they heard the unfamiliar person's voice.
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Gácsi, M., Kara, E., Belényi, B., Topál, J., & Miklósi, Á. (2009). The effect of development and individual differences in pointing comprehension of dogs. Anim. Cogn., 12(3), 471–479.
Abstract: In spite of the rather different procedures actually used in comparative studies to test the ability of different species to rely on the human pointing gesture, there is no debate on the high performance of dogs in such tasks. Very little is known, however, on the course through which they acquire this ability or the probable factors influencing the process. Important developmental questions have remained unsolved and also some methodological concerns should be addressed before we can convincingly argue for one interpretation or another. In this study we tested 180 dogs of different age (from 2 months to adults) to investigate their performance in the human distal momentary pointing gesture. The results, analyzed at both the group and the individual levels, showed no difference in the performance according to age, indicating that in dogs the comprehension of the human pointing may require only very limited and rapid early learning to fully develop. Interestingly, neither the keeping conditions nor the time spent in active interaction with the owner, and not even some special (agility) training for using human visual cues, had significant effect on the success and explained individual differences. The performance of the dogs was rather stable over time: during the 20 trials within a session and even when subsamples of different age were repeatedly tested. Considering that in spite of the general success at the group level, more than half of the dogs were not successful at the individual level, we revealed alternative “decision-making rules” other than following the pointing gesture of the experimenter.
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Gaunet, F. (2010). How do guide dogs and pet dogs (Canis familiaris) ask their owners for their toy and for playing? Anim. Cogn., 13(2), 311–323.
Abstract: Abstract When apes are not fully understood by humans, they persist with attempts to communicate, elaborating their behaviours to better convey their meaning. Such abilities have never been investigated in dogs. The present study aimed to clarify any effect of the visual attentional state of the owner on dogs’ (Canis familiaris) social-communicative signals for interacting with humans, and to determine whether dogs persist and elaborate their behaviour in the face of failure to communicate a request. Gaze at a hidden target or at the owner, gaze alternation between a hidden target and the owner, vocalisations and contacts in 12 guide and 12 pet dogs were analysed (i) when the dogs were asked by their owners (blind or sighted) to fetch their inaccessible toy and (ii) when the dogs were subsequently given an unfamiliar object (apparent unsuccessful communication) or their toy (apparent successful communication). No group differences were found, indicating no effect of the visual status of the owner on the dogs’ socio-communicative modes (i.e. no sensitivity to human visual attention). Results, however, suggest that the dogs exhibited persistence (but not elaboration) in their “showing” behaviours in each condition, except that in which the toy was returned. Thus, their communication was about a specific item in space (the toy). The results suggest that dogs possess partially intentional non-verbal deictic abilities: (i) to get their inaccessible toy, the dogs gazed at their owners as if to trigger their attention; gaze alternation between the owner and the target direction, and two behaviours directed at the target were performed, apparently to indicate the location of the hidden toy; (ii) after the delivery of the toy, the dogs behaved as if they returned to the play routine, gazing at their owner whilst holding their toy. In conclusion, this study shows that dogs possess partially intentional non-verbal deictic abilities: they exhibit successive visual orienting between a partner and objects, apparent attention-getting behaviours, no sensitivity to the visual status of humans for communication, and persistence in (but no elaboration of) communicative behaviours when apparent attempts to “manipulate” the human partner fail.
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