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Povinelli DJ, Gallup GG, Eddy TJ, Bierschwale DT, & Engstrom MC. (1997). Chimpanzees recognize themselves in mirrors. Anim. Behav., 53, 1083.
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Pongrácz, P., Miklósi, Á., Vida, V., & Csányi, V. (2005). The pet dogs ability for learning from a human demonstrator in a detour task is independent from the breed and age. Appl. Anim. Behav. Sci., 90(3), 309–323.
Abstract: There are many indications and much practical knowledge about the different tasks which various breeds of dogs are selected for. Correspondingly these different breeds are known to possess different physical and mental abilities. We hypothesized that commonly kept breeds will show differences in their problem solving ability in a detour task around a V-shaped fence, and also, that breed differences will affect their learning ability from a human demonstrator, who demonstrates a detour around the fence. Subjects were recruited in Hungarian pet dog schools. We compared the results of the 10 most common breeds in our sample when they were tested in the detour task without human demonstration. There was no significant difference between the latencies of detour, however, there was a trend that German Shepherd dogs were the quickest and Giant Schnauzers were the slowest in this test. For testing the social learning ability of dogs we formed three breed groups (“utility”, “shepherd” and “hunting”). There were no significant differences between these, all the breed groups learned equally well from the human demonstrator. However, we found that dogs belonging to the “shepherd” group looked back more frequently to their owner than the dogs in the “hunting” group. Further, we have found that the age of pet dogs did not affect their social learning ability in the detour task. Our results showed that the pet status of a dog has probably a stronger effect on its cognitive performance and human related behaviour than its age or breed. These results emphasize that socialization and common activities with the dog might overcome the possible breed differences, if we give the dogs common problem solving, or social learning tasks.
Keywords: Dog; Breed differences; Social learning
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Pongrácz, P., Miklósi, Á., Kubinyi, E., Topál, J., & Csányi, V. (2003). Interaction between individual experience and social learning in dogs. Anim. Behav., 65(3), 595–603.
Abstract: We investigated the interaction between individual experience and social learning in domestic dogs,Canis familiaris . We conducted two experiments using detour tests, where an object or food was placed behind a transparent, V-shaped wire-mesh fence, such that the dogs could get the reward by going around the fence. In some groups, two open doors were offered as an alternative, easier way to reach the reward. In experiment 1 we opened the doors only in trial 1, then closed them for trials 2 and 3. In experiment 2 other dogs were first taught to detour the fence with closed doors after they had observed a detouring human demonstrator, then we opened the doors for three subsequent trials. In experiment 1 all dogs reached the reward by going through the doors in trial 1, but their detouring performance was poor after the doors had been closed, if they had to solve the task on their own. However, dogs in the experimental group that were allowed to watch a detouring human demonstrator after the doors had been closed showed improved detouring ability compared with those that did not receive a demonstration of detouring. In experiment 2 the dogs tended to keep on detouring along the fence even if the doors had been opened, giving up a chance to get behind the fence by a shorter route. These results show that dogs can use information gained by observing a human demonstrator to overcome their own mistakenly preferred solution in a problem situation. In a reversed situation social learning can also contribute to a preference for a less adaptive behaviour. However, only repeated individual and social experience leads to a durable manifestation of maladaptive behaviour. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.
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Pongrácz, P., Miklósi, Á., Kubinyi, E., Gurobi, K., Topál, J., & Csányi, V. (2001). Social learning in dogs: the effect of a human demonstrator on the performance of dogs in a detour task. Anim. Behav., 62(6), 1109–1117.
Abstract: We recorded the behaviour of dogs in detour tests, in which an object (a favourite toy) or food was placed behind a V-shaped fence. Dogs were able to master this task; however, they did it more easily when they started from within the fence with the object placed outside it. Repeated detours starting from within the fence did not help the dogs to obtain the object more quickly if in a subsequent trial they started outside the fence with the object placed inside it. While six trials were not enough for the dogs to show significant improvement on their own in detouring the fence from outside, demonstration of this action by humans significantly improved the dogs' performance within two-three trials. Owners and strangers were equally effective as demonstrators. Our experiments show that dogs are able to rely on information provided by human action when confronted with a new task. While they did not copy the exact path of the human demonstrator, they easily adopted the detour behaviour shown by humans to reach their goal.
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Pompilio, L., & Kacelnik, A. (2005). State-dependent learning and suboptimal choice: when starlings prefer long over short delays to food. Anim. Behav., 70(3), 571–578.
Abstract: Recent studies have used labels such as `work ethics', `sunk costs' and `state-dependent preferences' for apparent anomalies in animals' choices. They suggest that preference between options relates to the options' history, rather than depending exclusively on the expected payoffs. For instance, European starlings, Sturnus vulgaris, trained to obtain identical food rewards from two sources while in two levels of hunger preferred the food source previously associated with higher hunger, regardless of the birds' state at the time of testing. We extended this experimentally and theoretically by studying starlings choosing between sources that differed not only in history but also in the objective properties (delay until reward) of the payoffs they delivered. Two options (PF and H) were initially presented in single-option sessions when subjects were, respectively, prefed or hungry. While option PF offered a delay until reward of 10 s in all treatments, option H delivered delays of 10, 12.5, 15 and 17.5 s in four treatments. When training was completed, we tested preference between the options. When delays in both options were equal (10 s), the birds strongly preferred H. When delay in H was 17.5 s, the birds were indifferent, with intermediate results for intermediate treatments. Preference was not mediated by disrupted knowledge of the delays. Thus, preferences were driven by past state-dependent gains, rather than by the joint effect of the birds' state at the time of choice and knowledge of the absolute properties of each alternative, as assumed in state-dependent, path-independent models of optimal choice.
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Pollard, J. C., & Littlejohn, R. P. (1996). The effects of pen size on the behaviour of farmed red deer stags confined in yards. Appl. Anim. Behav. Sci., 47(3-4), 247–253.
Abstract: To determine whether pen size affected the behaviour and welfare of farmed red deer confined temporarily in yards, four groups of ten 2-year-old stags were confined for 40 min or 2 days in each of spring and summer, in either large (5 m × 4 m ) or small (2.5 m × 4) pens. In the small pens, wall pacing and vertical/horizontal head movements at the walls were more frequently observed (P < 0.05) and were carried out by a greater percentage of the deer (P < 0.001), and distances between individuals were smaller (P < 0.01), than observations in the large pens. Aggressive activities varied seasonally, with head-butting and chasing being seen most frequently in the spring (P < 0.05) and biting and kicking being seen most frequently in the summer (P < 0.05), and the overall frequency of aggressive activities was low in summer. In spring, in small pens there were fewer threats to head-butt, head butts by moving animals, and less stepping activity than in large pens (P < 0.05). In summer, in small pens there were more threats to butt and more stepping activity than in the large pens (P < 0.05). In both seasons, aggressive activities were correlated with wall pacing (r = 0.58 and 0.55, respectively). It was concluded that the effect of pen size on the frequency and nature of aggressive and other activities varied seasonally. In order minimise aggression and stepping activity, small pens were favoured in spring and large pens were favoured in summer. However, in both seasons there were greater inter-individual distances and reduced pacing and head movements at the walls in large pens. This latter finding may indicate that the large pens were less aversive to the deer, regardless of season.
Keywords: Red deer; Handling; Density; Aggression; Farming
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Poling, A., Thomas, J., Hall-Johnson, E., & Picker, M. (1985). Self-control revisited: Some factors that affect autoshaped responding. Behav. Process., 10(1-2), 77–85.
Abstract: Pigeons were exposed to autoshaping procedures under which 50% of red key illuminations were followed by 9-sec food deliveries, and 50% of blue key illuminations were followed by 3-sec food deliveries. When all key illuminations were 6 sec, pigeons preferred the red stimulus. Subsequent manipulations demonstrated that preference could be shifted to the blue stimulus by either increasing the duration of the red stimulus or imposing a delay interval between the offset of that stimulus and food delivery. A final experiment demonstrated that, in two of three subjects, preference for key illuminations associated with longer, but delayed, food deliveries generally increased as the duration of all key illuminations was lengthened. These results, obtained under conditions where keypecking had no programmed consequences, are similar to those previously observed under procedures involving a positive response-food dependency.
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Poling, A., Temple, W., & Foster, T. M. (1996). The differential outcomes effect: A demonstration in domestic chickens responding under a titrating-delayed-matching-to-sample procedure. Behav. Process., 36(2), 109–115.
Abstract: The differential outcomes effect refers to the increase in speed of acquisition or terminal accuracy that occurs in discrimination training when each of two or more discriminative stimuli is correlated with a different outcome (e.g. type of reinforcer). The present study demonstrated this effect in domestic hens exposed to a titrating-delayed-matching-to-sample procedure, under which correct responses increased (and incorrect responses decreased) the delay between the offset of a sample stimulus and the onset of two comparison stimuli. Colors of key illumination (red, green) were used as sample and comparison stimuli and correct responses resulted in 1- or 4-s food deliveries. When 1-s food deliveries consistently followed correct responses to one key color and 4-s food deliveries followed correct responses to the other key color, the maximum delay reached by the hens and their overall accuracy was significantly higher than when 1- and 4-s food deliveries were randomly arranged following correct responses to both key colors. These data constitute the first demonstration of the differential outcomes effect in chickens, and in any species evaluated under a titrating-delayed-matching-to-sample procedure.
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Poisbleau, M., Jenouvrier, S., & Fritz, H. (2006). Assessing the reliability of dominance scores for assigning individual ranks in a hierarchy. Anim. Behav., 72(4), 835–842.
Abstract: The dominance score (number of wins divided by the total number of interactions) is the most widely used procedure in field studies to rank individuals. Its reliability depends on the number of interactions on which it is calculated. However, most authors use it without any estimate of the associated error. We describe the precision associated with a dominance score estimate as a function of the number of interactions on which it is based, and hence provide a tool to plan field protocols and effort. The precision error decreases according to a power function with increasing number of interactions, but with more precision for extreme scores for any given number of interactions. We discuss the fact that the minimum number of interactions should be based on the precision associated with the 50% score, the least precise of all scores. We also emphasize the trade-off between recording effort and precision of the estimator, and give an example of our choice of 26 interactions for fieldwork on ducks and geese. When comparing individual ranks based on dominance scores with ranks given by the dominance matrix, we found a good correlation, with more mismatches around the middle of the hierarchy. This was consistent with the precision calculated with our model. We conclude that dominance score is a reliable tool, but conclusions must take into account the number of interactions on which the calculations are done. We also discuss the importance of initial assumptions and sources of bias in field studies.
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Poisbleau, M., Fritz, H., Valeix, M., Perroi, P. - Y., Dalloyau, S., & Lambrechts, M. M. (2006). Social dominance correlates and family status in wintering dark-bellied brent geese, Branta bernicla bernicla. Anim. Behav., 71(6), 1351–1358.
Abstract: In many gregarious species, including ducks and geese, being dominant provides more benefits than costs, because dominants have better access to resources essential for survival or reproduction. In geese, being in better body condition during migration towards the breeding grounds positively influences reproductive success. However, underlying proximate mechanisms linking prebreeding body condition on the wintering grounds to breeding success remain poorly understood. We investigated social dominance correlates and family status, in three consecutive winters, in a free-ranging, migrating, dark-bellied brent goose population. Families with juveniles dominated pairs, and pairs dominated singletons. Dominance rank did not increase with the number of juveniles per family. Males were dominant over females. Social dominance and reproductive status for a given winter were significantly correlated with body mass, body size and body condition during the previous winter, suggesting that body condition in winter also affects subsequent breeding success and hence also dominance. Levels of testosterone and triiodothyronine were not correlated with immediate or later dominance or reproductive status. We discuss the role of family status as a signal of social status in determining reproductive strategies.
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