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Author Stanley, C.R.; Dunbar, R.I.M.
Title Consistent social structure and optimal clique size revealed by social network analysis of feral goats, Capra hircus Type Journal Article
Year 2013 Publication (up) Anim Behav Abbreviated Journal
Volume 85 Issue Pages
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Notes Approved no
Call Number Equine Behaviour @ team @ Stanley2013 Serial 6253
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Author Dunbar, R.I.; Dunbar, E.P.
Title Contrasts in social structure among black-and-white colobus monkey groups Type Journal Article
Year 1976 Publication (up) Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 24 Issue 1 Pages 84-92
Keywords Agonistic Behavior; Animals; *Colobus; Copulation; Female; *Haplorhini; *Hierarchy, Social; Male; *Social Dominance
Abstract Three types of Colobus guereza groups may be distinguished on the bases of size and composition, namely small one-male groups, large, one-male groups and multi-male groups. The social structure of each type of group is described in terms of the distribution of non-agonistic interactions, the frequency and distribution of agonistic behaviour and the organization of the roles of vigilance, territorial defence and leadership. A number of differences are found between the group types which appear to be related to the differences in group size and composition. It is suggested that these group types represent stages in the life-cycle of colobus groups, and that such an interpretation may help to resolve some of the conflicting reports in the literature.
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-3472 ISBN Medium
Area Expedition Conference
Notes PMID:817624 Approved no
Call Number Serial 2049
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Author Kudo, H.; Dunbar, R.I.M.
Title Neocortex size and social network size in primates Type Journal Article
Year 2001 Publication (up) Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 62 Issue 4 Pages 711-722
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Abstract Primates use social grooming to service coalitions and it has been suggested that these directly affect the fitness of their members by allowing them to reduce the intrinsic costs associated with living in large groups. We tested two hypotheses about the size of grooming cliques that derive from this suggestion: (1) that grooming clique size should correlate with relative neocortex size and (2) that the size of grooming cliques should be proportional to the size of the groups they have to support. Both predictions were confirmed, although we show that, in respect of neocortex size, there are as many as four statistically distinct grades within the primates (including humans). Analysis of the patterns of grooming among males and females suggested that large primate social groups often consist of a set of smaller female subgroups (in some cases, matrilinearly based coalitions) that are linked by individual males. This may be because males insert themselves into the interstices between weakly bonded female subgroups rather than because they actually hold these subunits together.
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ISSN 0003-3472 ISBN Medium
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 4726
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Author O'Connell, S.; Dunbar, R.I.M.
Title The perception of causality in chimpanzees (Pan spp.) Type Journal Article
Year 2005 Publication (up) Animal Cognition Abbreviated Journal Anim. Cogn.
Volume 8 Issue 1 Pages 60-66
Keywords Animals; *Association Learning; Awareness; *Concept Formation; Female; *Habituation, Psychophysiologic; Male; Pan paniscus/*psychology; Pan troglodytes/*psychology; Perception
Abstract Chimpanzees (Pan spp.) were tested on a habituation/dishabituation paradigm that was originally developed to test for comprehension of causality in very young human infants. Three versions of the test were used: a food item being moved by a hand, a human pushing another human off a chair to obtain a food item, and a film clip of natural chimpanzee behaviour (capturing and eating a monkey). Chimpanzees exhibited similar results to those obtained with human infants, with significantly elevated levels of looking on the dishabituation trials. Since the level of response was significantly greater on natural/unnatural sequences than on unnatural/natural sequences, we conclude that the chimpanzees were not responding just to novelty but rather to events that infringed their sense of natural causation.
Address Evolutionary Psychology Research Group, School of Biological Sciences, Biosciences Building, University of Liverpool, Liverpool, L69 7ZB, UK
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1435-9448 ISBN Medium
Area Expedition Conference
Notes PMID:15322943 Approved no
Call Number Equine Behaviour @ team @ Serial 2514
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Author Dunbar, R.I.M.
Title The social brain hypothesis and its implications for social evolution Type Journal Article
Year 2009 Publication (up) Annals of Human Biology Abbreviated Journal Annals of Human Biology
Volume 36 Issue 5 Pages 562-572
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Abstract The social brain hypothesis was proposed as an explanation for the fact that primates have unusually large brains for body size compared to all other vertebrates: Primates evolved large brains to manage their unusually complex social systems. Although this proposal has been generalized to all vertebrate taxa as an explanation for brain evolution, recent analyses suggest that the social brain hypothesis takes a very different form in other mammals and birds than it does in anthropoid primates. In primates, there is a quantitative relationship between brain size and social group size (group size is a monotonic function of brain size), presumably because the cognitive demands of sociality place a constraint on the number of individuals that can be maintained in a coherent group. In other mammals and birds, the relationship is a qualitative one: Large brains are associated with categorical differences in mating system, with species that have pairbonded mating systems having the largest brains. It seems that anthropoid primates may have generalized the bonding processes that characterize monogamous pairbonds to other non-reproductive relationships (?friendships?), thereby giving rise to the quantitative relationship between group size and brain size that we find in this taxon. This raises issues about why bonded relationships are cognitively so demanding (and, indeed, raises questions about what a bonded relationship actually is), and when and why primates undertook this change in social style.
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Publisher Taylor & Francis Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0301-4460 ISBN Medium
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Notes doi: 10.1080/03014460902960289 Approved no
Call Number Equine Behaviour @ team @ Serial 6546
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Author Dunbar, R.I.M.; McAdam, M.R.; O'connell, S.
Title Mental rehearsal in great apes (Pan troglodytes and Pongo pygmaeus) and children Type Journal Article
Year 2005 Publication (up) Behavioural Processes Abbreviated Journal Behav. Process.
Volume 69 Issue 3 Pages 323-330
Keywords Algorithms; Animals; Child; Child, Preschool; Food; Frontal Lobe/anatomy & histology/physiology; Humans; *Imagination; Pan troglodytes; Pongo pygmaeus; Problem Solving/*physiology; Psychomotor Performance/physiology; Reward
Abstract The ability to rehearse possible future courses of action in the mind is an important feature of advanced social cognition in humans, and the “social brain” hypothesis implies that it might also be a feature of primate social cognition. We tested two chimpanzees, six orangutans and 63 children aged 3-7 years on a set of four puzzle boxes, half of which were presented with an opportunity to observe the box before being allowed to open it (“prior view”), the others being given without an opportunity to examine the boxes before handling them (“no prior view”). When learning effects are partialled out, puzzle boxes in the “prior view” condition were opened significantly faster than boxes given in the “no prior view” condition by the children, but not by either of the great apes. The three species differ significantly in the speed with which they opened boxes in the “no prior view” condition. The three species' performance on this task was a function of relative frontal lobe volume, suggesting that it may be possible to identify quantitative neuropsychological differences between species.
Address Evolutionary Psychology Research Group, School of Biological Sciences, University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, UK. rimd@liv.ac.uk
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Series Volume Series Issue Edition
ISSN 0376-6357 ISBN Medium
Area Expedition Conference
Notes PMID:15896530 Approved no
Call Number Serial 2097
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Author Dunbar, R.I.M.
Title Male and female brain evolution is subject to contrasting selection pressures in primates Type Journal Article
Year 2007 Publication (up) BMC Biology Abbreviated Journal BMC Biol
Volume 5 Issue Pages 21
Keywords Animals; *Brain/physiology; *Evolution; Female; Humans; Male; *Selection (Genetics); *Sex Characteristics
Abstract The claim that differences in brain size across primate species has mainly been driven by the demands of sociality (the “social brain” hypothesis) is now widely accepted. Some of the evidence to support this comes from the fact that species that live in large social groups have larger brains, and in particular larger neocortices. Lindenfors and colleagues (BMC Biology 5:20) add significantly to our appreciation of this process by showing that there are striking differences between the two sexes in the social mechanisms and brain units involved. Female sociality (which is more affiliative) is related most closely to neocortex volume, but male sociality (which is more competitive and combative) is more closely related to subcortical units (notably those associated with emotional responses). Thus different brain units have responded to different selection pressures.
Address British Academy Centenary Research Project, School of Biological Sciences, University of Liverpool, Liverpool, UK. rimd@liv.ac.uk
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1741-7007 ISBN Medium
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Notes PMID:17493267 Approved no
Call Number Serial 2100
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Author Pérez-Barbería, F.J.; Shultz, S.; Dunbar, R.I.M.; Janis, C.
Title Evidence For Coevolution Of Sociality And Relative Brain Size In Three Orders Of Mammals Type Journal Article
Year 2007 Publication (up) Evolution Abbreviated Journal
Volume 61 Issue 12 Pages 2811-2821
Keywords Brain size, carnivores, coevolution, primates, sociality, ungulates
Abstract Abstract

As the brain is responsible for managing an individual's behavioral response to its environment, we should expect that large relative brain size is an evolutionary response to cognitively challenging behaviors. The “social brain hypothesis†argues that maintaining group cohesion is cognitively demanding as individuals living in groups need to be able to resolve conflicts that impact on their ability to meet resource requirements. If sociality does impose cognitive demands, we expect changes in relative brain size and sociality to be coupled over evolutionary time. In this study, we analyze data on sociality and relative brain size for 206 species of ungulates, carnivores, and primates and provide, for the first time, evidence that changes in sociality and relative brain size are closely correlated over evolutionary time for all three mammalian orders. This suggests a process of coevolution and provides support for the social brain theory. However, differences between taxonomic orders in the stability of the transition between small-brained/nonsocial and large-brained/social imply that, although sociality is cognitively demanding, sociality and relative brain size can become decoupled in some cases. Carnivores seem to have been especially prone to this.
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Notes doi: 10.1111/j.1558-5646.2007.00229.x Approved no
Call Number Equine Behaviour @ team @ Serial 4781
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Author Pérez-Barbería, F.J.; Shultz, S.; Dunbar, R.I.
Title Evidence for coevolution of sociality and relative brain size in three orders of mammals Type Journal Article
Year 2007 Publication (up) Evolution Abbreviated Journal
Volume 61 Issue Pages
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Call Number Equine Behaviour @ team @ Pérez-Barbería2007 Serial 6221
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Author Shi, J.; Dunbar, R.I.M.; Buckland, D.; Miller, D.
Title Dynamics of grouping patterns and social segregation in feral goats (Capra hircus) on the Isle of Rum, NW Scotland Type Journal Article
Year 2005 Publication (up) Mammalia Abbreviated Journal
Volume 69 Issue Pages
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Call Number Equine Behaviour @ team @ Shi2005 Serial 6257
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