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Author Paz-y-Miño C. G.; Bond, A.B.; Kamil, A.C.; Balda, R.P. doi  openurl
  Title Pinyon jays use transitive inference to predict social dominance Type Journal Article
  Year 2004 Publication Nature Abbreviated Journal Nature  
  Volume 430 Issue 7001 Pages (down) 778-781  
  Keywords Animals; Cognition/*physiology; Group Structure; Male; *Social Dominance; Songbirds/*physiology  
  Abstract Living in large, stable social groups is often considered to favour the evolution of enhanced cognitive abilities, such as recognizing group members, tracking their social status and inferring relationships among them. An individual's place in the social order can be learned through direct interactions with others, but conflicts can be time-consuming and even injurious. Because the number of possible pairwise interactions increases rapidly with group size, members of large social groups will benefit if they can make judgments about relationships on the basis of indirect evidence. Transitive reasoning should therefore be particularly important for social individuals, allowing assessment of relationships from observations of interactions among others. Although a variety of studies have suggested that transitive inference may be used in social settings, the phenomenon has not been demonstrated under controlled conditions in animals. Here we show that highly social pinyon jays (Gymnorhinus cyanocephalus) draw sophisticated inferences about their own dominance status relative to that of strangers that they have observed interacting with known individuals. These results directly demonstrate that animals use transitive inference in social settings and imply that such cognitive capabilities are widespread among social species.  
  Address Center for Avian Cognition, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA  
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  Series Volume Series Issue Edition  
  ISSN 1476-4687 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15306809 Approved no  
  Call Number refbase @ user @; Equine Behaviour @ team @ room B 3.029 Serial 352  
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Author Shettleworth, S.J. doi  openurl
  Title Cognitive science: rank inferred by reason Type Journal Article
  Year 2004 Publication Nature Abbreviated Journal Nature  
  Volume 430 Issue 7001 Pages (down) 732-733  
  Keywords Animals; Cognition/*physiology; Group Structure; Male; *Social Dominance; Songbirds/*physiology  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1476-4687 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15306792 Approved no  
  Call Number refbase @ user @ Serial 365  
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Author Zhou, W.-X.; Sornette, D.; Hill, R.A.; Dunbar, R.I.M. doi  openurl
  Title Discrete hierarchical organization of social group sizes Type Journal Article
  Year 2005 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci  
  Volume 272 Issue 1561 Pages (down) 439-444  
  Keywords Anthropology, Cultural; *Group Structure; Humans; *Models, Biological; *Social Behavior; *Social Environment  
  Abstract The 'social brain hypothesis' for the evolution of large brains in primates has led to evidence for the coevolution of neocortical size and social group sizes, suggesting that there is a cognitive constraint on group size that depends, in some way, on the volume of neural material available for processing and synthesizing information on social relationships. More recently, work on both human and non-human primates has suggested that social groups are often hierarchically structured. We combine data on human grouping patterns in a comprehensive and systematic study. Using fractal analysis, we identify, with high statistical confidence, a discrete hierarchy of group sizes with a preferred scaling ratio close to three: rather than a single or a continuous spectrum of group sizes, humans spontaneously form groups of preferred sizes organized in a geometrical series approximating 3-5, 9-15, 30-45, etc. Such discrete scale invariance could be related to that identified in signatures of herding behaviour in financial markets and might reflect a hierarchical processing of social nearness by human brains.  
  Address State Key Laboratory of Chemical Reaction Engineering, East China University of Science and Technology, Shanghai 200237, China  
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  Series Volume Series Issue Edition  
  ISSN 0962-8452 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15734699 Approved no  
  Call Number refbase @ user @ Serial 549  
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Author Cambefort, J.P. openurl 
  Title A comparative study of culturally transmitted patterns of feeding habits in the chacma baboon Papio ursinus and the vervet monkey Cercopithecus aethiops Type Journal Article
  Year 1981 Publication Folia Primatologica; International Journal of Primatology Abbreviated Journal Folia Primatol (Basel)  
  Volume 36 Issue 3-4 Pages (down) 243-263  
  Keywords Age Factors; Animals; *Cercopithecus; *Cercopithecus aethiops; Culture; *Feeding Behavior; Female; Group Structure; Learning; Male; *Papio; Social Class; Teaching  
  Abstract Japanese workers have studied social acquisition patterns of new feeding habits in Macaca fuscata which they have termed precultural. The present study investigates the same phenomenon in the chacma baboon and the vervet monkey in their natural habitat. The questions addressed are: (1) How a new feeding habit enters a troop and by which age and sex category, also how it is propagated? (2) When individuals are permitted with a choice between palatable and unpalatable food, can they learn by demonstration only or do they have to pass through a direct learning process? (3) Can the results from the above questions be explained by social parameters such as the social structure of the individual species? It was found that juvenile baboons discover new food and that after the discovery propagation is instantaneous. In vervets discovery is random among the age classes and propagation is slow and takes place through certain 'pivot' individuals. Both species fail to learn about palatability by demonstration but have to go through a direct learning process. This contrasts strongly with the forest baboon Mandrillus sphinx that have been shown to learn by demonstration. Socially, baboon juveniles stay closer to each other than the adults who force them to live at the periphery of the troop. Vervets again forage without precise sub-group formation. The link between social and cultural propagation and social structure is discussed on the basis of these findings.  
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  ISSN 0015-5713 ISBN Medium  
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  Notes PMID:7319426 Approved no  
  Call Number Serial 2087  
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Author Wolter, R.; Pantel, N.; Stefanski, V.; Möstl, E.; Krueger, K. doi  openurl
  Title The role of an alpha animal in changing environmental conditions Type Journal Article
  Year 2014 Publication Physiology & Behavior Abbreviated Journal Physiol. Behav.  
  Volume 133 Issue Pages (down) 236-243  
  Keywords Alpha male; Horse; Equus ferus przewalskii; Bachelor group; Group structure  
  Abstract Abstract The maintenance and development of conservation areas by grazing of large herbivores, such as Przewalski's horses, is common practice. Several nature conservation areas house male bachelor groups of this species. When males are needed for breeding they are removed from the groups, often without considering group compositions and individual social positions. However, alpha animals are needed for ensuring group stability and decision making in potentially dangerous situations in several species. To investigate the role of the alpha male in a bachelor group, we observed the behaviour of five Przewalski's horse males during the enlargement of their enclosure. We analyzed the group's social structure and movement orders, as well as the animals' connectedness, activity budgets, and whether they moved with preferred group members and how factors such as social rank influenced the horses' behaviour. We also investigated the excretion of glucocorticoid metabolites (GCM) via faeces of the horses while exploring a new area as a parameter of glucocorticoid production. Our results show that the alpha male is important for a bachelor group in changing environmental conditions. The alpha male had the highest level of connectedness within the group. When exploring the new environment, its position in the group changed from previously being the last to being the first. Furthermore the whole group behaviour changed when exploring the new area. The stallions showed reduced resting behavior, increased feeding and did not stay close to each other. We found that the excretion of glucocorticoid metabolites of most horses rose only marginally during the first days on the new area while only the alpha male showed a significant increased amount of glucocorticoid production during the first day of the enclosure enlargement.  
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  ISSN 0031-9384 ISBN Medium  
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  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5818  
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Author Suzuki, Y.; Toquenaga, Y. doi  openurl
  Title Effects of information and group structure on evolution of altruism: analysis of two-score model by covariance and contextual analyses Type Journal Article
  Year 2005 Publication Journal of theoretical biology Abbreviated Journal J. Theor. Biol.  
  Volume 232 Issue 2 Pages (down) 191-201  
  Keywords *Altruism; Analysis of Variance; *Communication; Cooperative Behavior; *Evolution; Game Theory; *Group Structure; Humans; Models, Genetic; Models, Psychological; Selection (Genetics); Trust  
  Abstract An altruistic individual has to gamble on cooperation to a stranger because it does not know whether the stranger is trustworthy before direct interaction. Nowak and Sigmund (Nature 393 (1998a) 573; J. Theor. Biol. 194 (1998b) 561) presented a new theoretical framework of indirect reciprocal altruism by image scoring game where all individuals are informed about a partner's behavior from its image score without direct interaction. Interestingly, in a simplified version of the image scoring game, the evolutionarily stability condition for altruism became a similar form of Hamilton's rule, i.e. inequality that the probability of getting correct information is more than the ratio of cost to benefit. Since the Hamilton's rule was derived by evolutionarily stable analysis, the evolutionary meaning of the probability of getting correct information has not been clearly examined in terms of kin and group selection. In this study, we applied covariance analysis to the two-score model for deriving the Hamilton's rule. We confirmed that the probability of getting correct information was proportional to the bias of altruistic interactions caused by using information about a partner's image score. The Hamilton's rule was dependent on the number of game bouts even though the information reduced the risk of cooperation to selfish one at the first encounter. In addition, we incorporated group structure to the two-score model to examine whether the probability of getting correct information affect selection for altruism by group selection. We calculated a Hamilton's rule of group selection by contextual analysis. Group selection is very effective when either the probability of getting correct information or that of future interaction, or both are low. The two Hamilton's rules derived by covariance and contextual analyses demonstrated the effects of information and group structure on the evolution of altruism. We inferred that information about a partner's behavior and group structure can produce flexible pathways for the evolution of altruism.  
  Address Integrative Environmental Sciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1, Ten-Nou-Dai, Tsukuba, Ibaraki 305-8572, Japan. yukari@pe.ies.life.tsukuba.ac.jp  
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  Series Volume Series Issue Edition  
  ISSN 0022-5193 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15530489 Approved no  
  Call Number refbase @ user @ Serial 556  
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Author Jacobs, A.; Maumy, M.; Petit, O. url  doi
openurl 
  Title The influence of social organisation on leadership in brown lemurs (Eulemur fulvus fulvus) in a controlled environment Type Journal Article
  Year 2008 Publication Behavioural Processes Abbreviated Journal Behav. Process.  
  Volume 79 Issue 2 Pages (down) 111-113  
  Keywords Animals; *Decision Making; Dominance-Subordination; *Exploratory Behavior; Female; Group Structure; *Leadership; Lemur/*psychology; Male; Sex Factors; *Social Environment  
  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.  
  Address IPHC-DEPE, Equipe d'ethologie des primates, UMR 7178, Centre National de la Recherche Scientifique-Universite Louis Pasteur and Centre de Primatologie, Strasbourg, France  
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  ISSN 0376-6357 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:18586413 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5127  
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