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Zentall, T. R. (2006). Imitation: definitions, evidence, and mechanisms. Anim. Cogn., 9(4), 335–353.
Abstract: Imitation can be defined as the copying of behavior. To a biologist, interest in imitation is focused on its adaptive value for the survival of the organism, but to a psychologist, the mechanisms responsible for imitation are the most interesting. For psychologists, the most important cases of imitation are those that involve demonstrated behavior that the imitator cannot see when it performs the behavior (e.g., scratching one's head). Such examples of imitation are sometimes referred to as opaque imitation because they are difficult to account for without positing cognitive mechanisms, such as perspective taking, that most animals have not been acknowledged to have. The present review first identifies various forms of social influence and social learning that do not qualify as opaque imitation, including species-typical mechanisms (e.g., mimicry and contagion), motivational mechanisms (e.g., social facilitation, incentive motivation, transfer of fear), attentional mechanisms (e.g., local enhancement, stimulus enhancement), imprinting, following, observational conditioning, and learning how the environment works (affordance learning). It then presents evidence for different forms of opaque imitation in animals, and identifies characteristics of human imitation that have been proposed to distinguish it from animal imitation. Finally, it examines the role played in opaque imitation by demonstrator reinforcement and observer motivation. Although accounts of imitation have been proposed that vary in their level of analysis from neural to cognitive, at present no theory of imitation appears to be adequate to account for the varied results that have been found.
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Peltzer, K., Mabilu, M. G., Mathoho, S. F., Nekhwevha, A. P., Sikhwivhilu, T., & Sinthumule, T. S. (2006). Trauma history and severity of gambling involvement among horse-race gamblers in a South African gambling setting. Psychol Rep, 99(2), 472–476.
Abstract: The purpose of this study was to ascertain the frequency of gambling involvement and the prevalence of problem gambling among horse race gamblers and to discover whether problem gambling in this sample is associated with a history of trauma. Among a sample of 266 South African horse-race gamblers (94% men and 6% women, Mage 46.8 yr., SD = 13.9, range 18-85 years), 31.2% were classified as probable pathological gamblers and 19.9% with problem gambling. Major weekly gambling activities included racetrack betting (82%), purchase of lottery tickets or scratch tickets (35%), purchase of sports lottery tickets (23%), and using casino type games (18%). Trauma history was significantly associated with gambling severity.
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Kralj-Fiser, S., Scheiber, I. B. R., Blejec, A., Moestl, E., & Kotrschal, K. (2007). Individualities in a flock of free-roaming greylag geese: behavioral and physiological consistency over time and across situations. Horm Behav, 51(2), 239–248.
Abstract: The concept of personality implies individual differences in behavior and physiology that show some degree of repeatability/consistency over time and across contexts. Most studies of animal personality, particularly studies of individuals' variation in physiological mechanisms, have been conducted on selected individuals in controlled conditions. We attempted to detect consistent behaviors as well as physiological patterns in greylag ganders (Anser anser) from a free-roaming flock living in semi-natural conditions. We tested 10 individuals repeatedly, in a handling trial, resembling tests for characterization of “temperaments” in captive animals. We recorded the behavior of the same 10 individuals during four situations in the socially intact flock: (1) a “low density feeding condition”, (2) a “high density feeding condition”, (3) a “low density post-feeding situation” and (4) while the geese rested. We collected fecal samples for determination of excreted immuno-reactive corticosterone (BM) and testosterone metabolites (TM) after handling trials, as well as the “low density feeding” and the “high density feeding” conditions. BM levels were very highly consistent over the repeats of handling trials, and the “low density feeding condition” and tended to be consistent over the first two repeats of the “high density feeding condition”. Also, BM responses tended to be consistent across contexts. Despite seasonal variation, there tended to be inter-test consistency of TM, which pointed to some individual differences in TM as well. Aggressiveness turned out to be a highly repeatable trait, which was consistent across social situations, and tended to correlate with an individual's resistance during handling trials. Also, “proximity to the female partner” and “sociability” – the average number of neighboring geese in a close distance while resting – were consistent. We conclude that aggressiveness, “affiliative tendencies” and levels of excreted corticosterone and testosterone metabolites may be crucial factors of personality in geese.
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Reimers, M., Schwarzenberger, F., & Preuschoft, S. (2007). Rehabilitation of research chimpanzees: stress and coping after long-term isolation. Horm Behav, 51(3), 428–435.
Abstract: We report on the permanent retirement of chimpanzees from biomedical research and on resocialization after long-term social isolation. Our aim was to investigate to what extent behavioral and endocrine measures of stress in deprived laboratory chimpanzees can be improved by a more species-typical social life style. Personality in terms of novelty responses, social dominance after resocialization and hormonal stress susceptibility were affected by the onset of maternal separation of infant chimpanzees and duration of deprivation. Chimpanzees, who were separated from their mothers at a younger age and kept in isolation for more years appeared to be more timid personalities, less socially active, less dominant and more susceptible to stress, as compared to chimpanzees with a less severe deprivation history. However, permanent retirement from biomedical research in combination with therapeutic resocialization maximizing chimpanzees' situation control resulted in reduced fecal cortisol metabolite levels. Our results indicate that chimpanzees can recover from severe social deprivation, and may experience resocialization as less stressful than solitary housing.
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Robert, N., Walzer, C., Ruegg, S. R., Kaczensky, P., Ganbaatar, O., & Stauffer, C. (2005). Pathologic findings in reintroduced Przewalski's horses (Equus caballus przewalskii) in southwestern Mongolia. J Zoo Wildl Med, 36(2), 273–285.
Abstract: The Przewalski's horse (Equus caballus przewalskii) was extinct in the wild by the mid 1960s. The species has survived because of captive breeding only. The Takhin Tal reintroduction project is run by the International Takhi Group; it is one of two projects reintroducing horses to the wild in Mongolia. In 1997 the first harem group was released. The first foals were successfully raised in the wild in 1999. Currently, 63 Przewalski's horses live in Takhin Tal. Little information exists on causes of mortality before the implementation of a disease-monitoring program in 1998. Since 1999, all dead horses recovered (n = 28) have been examined and samples collected and submitted for further investigation. Equine piroplasmosis, a tick-transmitted disease caused by Babesia caballi or Theileria equi, is endemic in Takhin Tal and was identified as the cause of death of four stallions and one stillborn foal. In December 2000, wolf predation was implicated in the loss of several Przewalski's horses. However, thorough clinical, pathologic, and bacteriologic investigations performed on dead and surviving horses of this group revealed lesions compatible with strangles. The extreme Mongolian winter of 2000-2001 is thought to have most probably weakened the horses, making them more susceptible to opportunistic infection and subsequent wolf predation. Other occasional causes of death since 1999 were trauma, exhaustion, wasting, urolithiasis, pneumonia, abortion, and stillbirth. The pathologic examination of the Przewalski's horses did not result in a definitive diagnosis in each case. Several disease factors were found to be important in the initial phase of the reintroduction, which could potentially jeopardize the establishment of a self-sustaining population.
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Li, C., Jiang, Z., Tang, S., & Zeng, Y. (2007). Influence of enclosure size and animal density on fecal cortisol concentration and aggression in Pere David's deer stags. Gen Comp Endocrinol, 151(2), 202–209.
Abstract: We investigated the impact of enclosure size and animal density on behavior and adrenocortical secretion in Pere David's deer in Dafeng Nature Reserve, China. From February 15 to April 16 in 2004, we conducted two experiments. First, we studied maintenance behavior and conflict behavior of Pere David's deer stags in a large enclosure (200 ha) with low animal density (0.66 deer/ha) and a small display pen (0.75 ha) with high animal density (25.33 deer/ha). The maintenance behavior we recorded included standing, locomotion, foraging and rest. During the behavioral observations, we collected fresh voided fecal samples from the stags periodically, and analyzed the fecal cortisol concentrations in those samples using radioimmunoassay technique. Second, we monitored the fecal cortisol concentrations of one group of stags (12 deer lived in an enclosure of 100 ha) before and after transferred into a small pen (0.5 ha). We found that in the first experiment: (1) there were significant differences in standing and rest whereas no significant differences of locomotion and foraging between the free-ranging group and the display group; (2) frequency of conflict behavior in the display group was significantly higher than those in the free-ranging group; and (3) fecal cortisol concentration of the display group (326.17+/-16.98 ng/g dry feces) was significantly higher than that of the free-ranging group (268.98+/-15.21 ng/g dry feces). In the second experiment, there was no significant difference of the fecal cortisol concentrations among sampling days, but the mean fecal cortisol concentration of the day after transferring (337.46+/-17.88 ng/g dry feces) was significantly higher than that of the day before transferring (248.44+/-7.99 ng/g dry feces). Comparison with published findings, our results indicated that enclosure size and animal density affect not only behaviors, but also adrenocortical secretion in Pere David's deer. Small living space with high animal density may impose physiological stress to captive Pere David's deer. Moreover, long-term physiological stress and increase of conflict behavior may subsequently affect survival and reproduction of the deer.
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Heinrich, B., & Bugnyar, T. (2007). Just how smart are ravens? Sci Am, 296(4), 64–71.
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Jacobs, A., Maumy, M., & Petit, O. (2008). The influence of social organisation on leadership in brown lemurs (Eulemur fulvus fulvus) in a controlled environment. Behav. Process., 79(2), 111–113.
Abstract: Studies on leadership during group movements in several lemur species showed that females were responsible for the travelling choices concerning time and direction. Interestingly, in these species females are dominant over males. We investigated the influence of social organisation upon leadership processes by studying a lemur species in which social organisation is characterized by the absence of female dominance: the brown lemur (Eulemur fulvus fulvus). The study was conducted on a semi-free ranging group of 11 individuals and the analysis performed on 69 group movements showed that all the individuals could initiate a group movement. In 34 cases, the whole group moved. There was no significant difference in the number of start attempts or in the number of group members involved from one initiator to another. Moreover, there was no effect of sex or age of the initiator on the number of individuals following it or on the speed of the joining process. Therefore, the leadership observed is widely distributed to all group members. These results support the hypothesis of an influence of social organisation upon the decision-making processes but still remain to be studied in a more relevant ecological context.
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Cancedda, M. (1990). [Social and behavioral organization of horses on the Giara (Sardinia): distribution and aggregation]. Boll Soc Ital Biol Sper, 66(11), 1089–1096.
Abstract: In this paper some considerations on the environment of the 42 Kmq of the volcanic-basaltic Giara tableland are discussed. Conditioning by the environment and its effect on the distribution of a population of 712 horses is illustrated in view of their social and behavioural organization.
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Cheney, D. L., & Seyfarth, R. M. (1990). The representation of social relations by monkeys. Cognition, 37(1-2), 167–196.
Abstract: Monkeys recognize the social relations that exist among others in their group. They know who associates with whom, for example, and other animals' relative dominance ranks. In addition, monkeys appear to compare types of social relations and make same/different judgments about them. In captivity, longtailed macaques (Macaca fascicularis) trained to recognize the relation between one adult female and her offspring can identify the same relation among other mother-offspring pairs, and distinguish this relation from bonds between individuals who are related in a different way. In the wild, if a vervet monkey (Cercopithecus aethiops) has seen a fight between a member of its own family and a member of Family X, this increases the likelihood that it will act aggressively toward another member of Family X. Vervets act as if they recognize some similarity between their own close associates and the close associates of others. To make such comparisons the monkeys must have some way of representing the properties of social relationships. We discuss the adaptive value of such representations, the information they contain, their structure, and their limitations.
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