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Author Dunbar, R.I.M.; Shultz, S. doi  openurl
  Title Understanding primate brain evolution Type Journal Article
  Year 2007 Publication Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences Abbreviated Journal Philos Trans R Soc Lond B Biol Sci  
  Volume 362 Issue 1480 Pages 649-658  
  Keywords  
  Abstract We present a detailed reanalysis of the comparative brain data for primates, and develop a model using path analysis that seeks to present the coevolution of primate brain (neocortex) and sociality within a broader ecological and life-history framework. We show that body size, basal metabolic rate and life history act as constraints on brain evolution and through this influence the coevolution of neocortex size and group size. However, they do not determine either of these variables, which appear to be locked in a tight coevolutionary system. We show that, within primates, this relationship is specific to the neocortex. Nonetheless, there are important constraints on brain evolution; we use path analysis to show that, in order to evolve a large neocortex, a species must first evolve a large brain to support that neocortex and this in turn requires adjustments in diet (to provide the energy needed) and life history (to allow sufficient time both for brain growth and for 'software' programming). We review a wider literature demonstrating a tight coevolutionary relationship between brain size and sociality in a range of mammalian taxa, but emphasize that the social brain hypothesis is not about the relationship between brain/neocortex size and group size per se; rather, it is about social complexity and we adduce evidence to support this. Finally, we consider the wider issue of how mammalian (and primate) brains evolve in order to localize the social effects.  
  Address British Academy Centenary Research Project, School of Biological Sciences, University of Liverpool, Liverpool L69 7ZB, UK. rimd@liv.ac.uk  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (up) English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0962-8436 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17301028 Approved no  
  Call Number Serial 2099  
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Author Dunbar, R.I.M. doi  openurl
  Title Male and female brain evolution is subject to contrasting selection pressures in primates Type Journal Article
  Year 2007 Publication 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  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language (up) English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1741-7007 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:17493267 Approved no  
  Call Number Serial 2100  
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Author O'Connell, S.; Dunbar, R.I.M. doi  openurl
  Title The perception of causality in chimpanzees (Pan spp.) Type Journal Article
  Year 2005 Publication 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 (up) 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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