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Coevolution of neocortical size, group size and language in humans

  • R. I. M. Dunbar (a1)

Group size covaries with relative neocortical volume in nonhuman primates. This regression equation predicts a group size for modern humans very similar to that for hunter-gatherer and traditional horticulturalist societies. Similar group sizes are found in other contemporary and historical societies. Nonhuman primates maintain group cohesion through social grooming; among the Old World monkeys and apes, social grooming time is linearly related to group size. Maintaining stability of human-sized groups by grooming alone would make intolerable time demands. It is therefore suggested (1) that the evolution of large groups in the human lineage depended on developing a more efficient method for time-sharing the processes of social bonding and (2) that language uniquely fulfills this requirement. Data on the size of conversational and other small interacting groups of humans accord with the predicted relative efficiency of conversation compared to grooming as a bonding process. In human conversations about 60% of time is spent gossiping about relationships and personal experiences. Language may accordingly have evolved to allow individuals to learn about the behavioural characteristics of other group members more rapidly than was feasible by direct observation alone.

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L. C. Aiello & R. I. M. Dunbar (1993) Neocortex size, group size, and the evolution of language. Current Anthropology 34:184–93. [arRIMD]

R. J. Andrew (1976) Use of formants in the grunts of baboons and other nonhuman primates. In: Annals of the New York Academy of Sciences: 280. Origins and evolution of language and speech, ed. S. R. Hamad , H. D. Steklis & J. Lancaster . New York Academy of Sciences. [LM]

E. Armstrong , K. Zilles , M. Curtis & A. Schleicher (1991) Cortical folding, the lunate sulcus and the evolution of the human brain. Journal of Human Evolution 20:341–48. [DF]

R. Axelrod & D. Dion (1989) The further evolution of cooperation. Science 242:1385–90. [AHH]

L. T. Ballance (1990) Residence patterns, group organization, and surfacing associations of bottlenose dolphins in Kino Bay, Gulf of California, Mexico. In: The bottlenose dolphin, ed. S. Leatherwood & R. R. Reeves . Academic Press. [BJ]

R. A. Barton (1985) Grooming site preferences in primates and their functional implications. International Journal of Primatology 6:519–31. [rRIMD.AW]

J. B. Birdsell (1970) Local group composition among the Australian aborigines: A critique of the evidence from fieldwork conducted since 1930. Current Anthropology 11:115–42. [aRIMD]

B. Blumenberg (1983) The evolution of the advanced hominid brain. Current Anthropology 24:589623. [aRIMD]

S. Boinski (1988) Sex differences in the foraging behavior of squirrel monkeys in a seasonal habitat. Behavioral Ecology and Sociohiology 23:177–86. [CHJ]

S. Boinski (1991) The coordination of spatial position: A field study of the vocal behavior of adult female squirrel monkeys. Animal Behaviour 41:89102. [BJ.CHJ]

S. Boinski (1993) Vocal coordination of troop movement among white-faced capuchin monkeys, Cebus capucinus. American Journal of Primatology 30:85100. [BJ]

S. Boinski & C. L. Mitchell (1992) Ecological and social factors affecting the vocal behavior of adult female squirrel monkeys. Ethology 92:316–30. [CHJ]

E. D. Brown & S. M. Farnbough (1991) Song sharing in Australian magpie, Gymnorhina tibicens. Behaviour 118:244–74. [RJA]

R. Burling (1993) Primate calls, human language and nonverbal communication. Current Anthropology 34:2554. [rRIMD]

C. J. Buys & K. L. Larsen (1979) Human sympathy groups. Psychological Report 45:547–53. [aRIMD]

R. W. Byrne (1994) The evolution of intelligence. In: The evolution of behaviour, ed. P. J. B. Slater & T. R. Halliday . Cambridge University Press. [RWB]

R. W. Byrne & A. Whiten (1985) Tactical deception of familiar individuals in baboons (Papio ursinus). Animal Behaviour 33:669–73. [RWB]

R. W. Byrne & A. Whiten (1992) Cognitive evolution in primates: Evidence from tactical deception. Man 27:609–27. [RWB]

W. H. Calvin (1982) Did throwing stones shape hominid brain evolution? Ethology and Sociobiology 3:115–24. [BJ]

R. L. Carneiro (1970) A theory of the origin of the state. Science 169:733–38. [RBG]

R. L. Carneiro (1988) The circumspection theory: Challenge and response. American Behavioral Scientist 31:497511. [RBG]

D. Cheney (1992) Intragroup cohesion and intergroup hostility: The relationship between grooming distributions and intergroup competition among female primates. Behavioral Ecology 3(4):334. [aRIMD.MH.BJ]

D. L. Cheney & R. M. Seyfarth (1982) How vervet monkeys perceive their grunts: Field playback experiments. Animal Behaviour 30:739–51. [aRIMD.LM]

A. S. Clarke , W. Mason & G. P. Moberg (1988) Differential behavioral and adrenocortical responses to stress among three macaque species. American Journal of Primatology 14:3752. [BJ]

C. R. Cloninger & S. B. Gilligan (1987) Neurogenetic mechanisms of learning: A phylogenetic perspective. Journal of Psychiatric Research 21(4):457–72. [BJ]

T. H. Clutton-Brock & P. H. Harvey (1977a) Primate ecology and social organization. Journal of Zoology (London) 183:139. [AHH]

J. E. Cohen (1971) Casual groups of monkeys and men. Harvard University Press. [aRIMD]

M. C. Corballis (1992) On the evolution of language and generativity. Cognition 44:197226. [MCC]

V. Dasser (1988) A social concept in Java monkeys. Animal Behaviour 36:225–30. [RMS]

J. A. Davis (1967) Clustering and structural balance in graphs. Human Relations 20:181–87. [LCF]

T. W. Deacon (1990) Fallacies of progression in theories of brain-size evolution. International Journal of Primatology 11:193236. [rRIMD]

I. de Sola Poole & M. Kochen (1978) Contacts and influence. Social Networks 1:551. [LCF]

C. B. DeSoto (1960) Learning a social structure. Journal of Abnormal and Social Psychology 60:417–21. [LCF]

F. de Waal & L. M. Luttrell (1986) The similarity principle underlying social bonding among female rhesus monkeys. Folia Primatologica 46:215–34. [aRIMD]

R. I. M. Dunbar (1988) Primate social systems. Chapman & Hall and Cornell University Press. [arRIMD, RAF, BJ]

R. I. M. Dunbar (1989b) Ecological modelling in an evolutionary context. Folia Primatologica 53:235–46. [aRIMD]

R. I. M. Dunbar (1991) Functional significance of social grooming in primates. Folia Primatologica 57:121–31. [arRIMD, MC, CHJ, EPM]

R. I. M. Dunbar (1992b) Time: A hidden constraint on the behavioural ecology of baboons. Behavioral Ecology and Sociobiology 31:3549. [arRIMD.RAF.AHH]

R. I. M. Dunbar (1992c) Behavioural ecology of the extinet papionines. Journal of Human Evolution 22:407–21. [rKIMO]

R. I. M. Dunbar (1993) Socioecology of the extinet theropiths: A modelling approach. In: Theropithecus: The rise and fall of a primate genus, ed. N. G. Jablonski . Cambridge University Press. [rRIMD]

R. I. M. Dunbar , D. Buckland & D. Miller (1990) Mating strategies of male feral goats: A problem in optimal foraging. Animal Behaviour 40:653–67. [rRIMD]

R. I. M. Dunbar & P. Dunbar (1980) The pairbond in klispringer. Animal Behaviour 28:219–29. [rRIMD]

R. I. M. Dunbar & P. Dunbar (1981) Grouping behaviour of male walia ibex, with special reference to the rut. African Journal of Ecology 19:251–63. [rRIMD]

R. I. M. Dunbar & S. C. Roberts (1992) Territory quality in mountain reedbuck (Redunca fulvonifula chanleri): Distance to safety. Ethology 90:134–42. [rRIMD]

N. Emler (1990) A social psychology of reputation. European Review of Social Psychology 1:171–93. [AW]

M. Enquist & O. Leimar (1993) The evolution of cooperation in mobile organisms. Animal Behaviour 45:747–57. [rRIMD]

P. G. H. Evans (1987) The natural history of whales and dolphins. Facts on File Publication. [BJ]

D. Falk (1983) Cerebral cortices of East African early hominids. Science 221:1072–74. [DF]

D. Falk , C. Hildebolt & M. W. Vannier (1989) Reassessment of the Taung early hominid from a neurological perspective. Journal of Human Evolution 18:485–92. [DF]

J. Felsenstein (1985) Phylogenies and the comparative method. American Naturalist 125:115. [RAB.EPM]

I. Ferrer & M. Perera (1988) Structure and nerve cell organization in the cerebral cortex of the dolphin Stennela coertileoalba, a Golgi study. Anatomy and Embryology 178:161–73. [BJ]

H. E. Fisher (1989) Evolution of human serial pairbonding. American Journal of Physical Anthropology 78:331–54. [IIG]

R. A. Foley (1993) The influence of seasonality on hominid evolution. In: Seasonality and human evolution, ed. S. J. Ulijaszek & S. Strickland . Cambridge University Press. [RAF]

R. A. Foley & P. C. Lee (1989) Finite social space, evolutionary pathways and reconstructing hominid behavior. Science 243:901–6. [RAF]

R. A. Foley & P. C. Lee (1991) Ecology and energetics of encephalization in hominid evolution. Philosophical Transactions of the Royal Society of London, Series B 334:223–32. [RAF]

L. C. Freeman (1992a) Filling in the blanks: A theory of cognitive categories and the structure of social affiliation. Social Psychology Quarterly 55:118–27. [LCF]

L. C. Freeman (1992b) The sociological concept of “group”: An empirical test of two models. American Journal of Sociology 98:152–66. [LCF]

L. J. Garey , E. Winkelmann & K. Brauer (1985) Golgi and Nissl studies of the visual cortex of the bottlenose dolphin. Journal of Comparative Neurology 240:305–21. [BJ]

V. Geist (1978) Life strategies, human evolution, environmental design. Springer-Verlag. [MEH]

P. S. Goldman-Rakic (1988) Topography of cognition: Parallel distributed networks in primate association cortex. Annual Review of Neuroscience 11:137–50. [MH]

S. Gouzoules , H. Gouzoules & P. Marler (1984) Rhesus monkey (Macaca mulatta) screams: Representational signalling in the recruitment of agonistic aid. Animal Behaviour 32:182–93. [AHH.AW]

R. B. Graber (1991) Population pressure, agricultural origins, and cultural evolution: Constrained mobility or inhibited expansion? American Anthropologist 93:692–95. [RBG]

A. Grafen (1989) The phylogenetic regression. Philosophical Transactions of the Royal Society, Scries B 326:119–57. [RAU.EPM]

W. D. Hamilton (1964) The genetical theory of social behavior, I, II. Journal of Theoretical Biology 7:152. [CLB]

L. J. Hansen (1990) California coastal bottlenose dolphins. In: The bottlenose dolphin, ed. S. Leatherwood & R. R. Reeves . Academic Press. [BJ]

M. D. Hauser (1992a) Articulatory and social factors influence the acoustic structure of rhesus monkey vocalizations: A learned mode of production? Journal of the Acoustical Society of America 91:2175–79. [MH]

M. D. Hauser (1992c) Costs of deception: Cheaters are punished in rhesus monkeys (Macaco mulatta) Proceedings of the National Academy of Sciences 89:12137–39. [AHH]

M. D. Hauser & C. Fowler (1991) Declination in fundamental frequency is not unique to human speech: Evidence from nonhuman primates. Journal of the Acoustical Society of America 91:363–69. [MH]

G. W. Hewes (1973) Primate communication and the gestural origins of language. Current Anthropology 14:524. [MCC]

J. D. Higley , P. T. Mehlman , D. M. Taub , S. B. Higley , S. J. Suomi , M. Linnoila & J. H. Vickers (1992) Cerebralspinal fluid monoamine and adrenal correlates of aggression in free-ranging rhesus monkeys. Archives of General Psychiatry 49:436–41. [BJ]

M. A. Hofman (1982) Encephalization in mammals in relation to the size of the cerebral cortex. Brain Behavior & Evolution 20:8496. [IIG]

M. A. Hofman (1985) Size and shape of the cerebral cortex in mammals. Brain Behavior & Evolution 27:2840. [IIG]

M. A. Hofman (1988) Size and shape of the cerebral cortex in mammals. I. The cortical surface. Brain Behavior & Evolution 32:1726. [IIG]

M. A. Hofman (1989) On the evolution and geometry of the brain in mammals. Progress in Neurobiology 32:137–58. [IIG]

R. L. Holloway (1966) Cranial capacity and neuron number: Critique and proposal. American Journal of Physical Anthropology 25:305–14. [RLH]

R. L. Holloway (1974) On the meaning of brain size. Review of Jerison's Evolution of the brain and intelligence. Science 184:677–79. [RLH]

R. L. Holloway (1979) Brain size, allometry, and reorganization: Toward a synthesis. In: Development and evolution of brain size: Behavioral implications, ed. M. E. Hahn , C. Jensen & B. C. Dudek . Academic Press. [RLH]

R. L. Holloway (1981) Cultural systems and brain evolution. Dialectical Anthropology 5:287303. [RLH]

R. L. Holloway (1992) The failure of the Gyrification Index (GI) to account for the volumetric reorganization in the evolution of the human brain. Journal of Human Evolution 22:163–70. [RLH]

R. L. Holloway & D. Post (1982) The relativity of relative brain measures and hominid evolution. In: Primate brain evolution, ed. E. Armstrong & D. Falk . Plenum Press. [RLH]

J. L. Hoogland (1983) Nepotism and alarm calling in the black-tailed prairie dog, Cynomys ludovicianus. Animal Behaviour 31:472–79. [AHH]

B. P. Indik (1965) Organisation size and member participation: Some empirical tests of alternative hypotheses. Human Relations 18:339–50. [aRIMD]

T. Iwamoto & R. I. M. Dunbar (1983) Thermoregulation, habitat quality and the behavioural ecology of gelada baboons. Journal of Animal Ecology 52:357–66. [arRIMD]

B. Jacobs , M. Schall & A. B. Scheibel (1993) A quantitative dendritic analysis of Wernicke's area in humans. II. Gender, hemispheric, and environmental factors. Journal of Comparative Neurology 327:97111. [BJ]

J. James (1952) A preliminary study of the size determinant in small group interaction. American Sociological Review 16:474–77. [aRIMD]

J. James (1953) The distribution of free-forming small group size. American Sociological Review 18:569–70. [aRIMD]

R. Jarvenpa & H. Brumbach (1988) Socio-spatial organization and decision-making processes: Observations from the Chipewyan. American Anthropologist 90:598618. [RJ]

H. J. Jerison (1973) Evolution of the brain and intelligence. Academic Press. [aRIMD, IIG, RLH]

H. J. Jerison (1988) Evolutionary biology of intelligence: The nature of the problem. In: Intelligence and evolutionary biology, ed. H. J. Jerison & I. Jerison . Springer-Verlag. [HJJ]

H. J. Jerison (1991a) Fossil brains and the evolution of the neocortex. In: The neocortex:Ontogeny and phylogeny, ed. B. Finlay , G. Innocenti & H. Scheich . Plenum Press. [HJJ]

A. Jolly (1969) Lemur social behaviour and primate intelligence. Science 153:501–6. [aRIMD]

R. F. Kay , J. M. Plavcan , K. E. Glander & P. C. Wright (1988) Sexual selection and canine dimorphism in New World monkeys. American Journal of Physical Anthropology 77:385–97. [DD]

P. D. Killworth , H. R. Bernard & C. McCarty (1984) Measuring patterns of acquaintanceship. Current Anthropology 25:391–97. [aRIMD]

W. G. Kinzey & P. C. Wright (1982) Grooming behavior in the titi monkey, Callicebus torquatus. American Journal of Primatology 3 (1–4):267–75. [IIG]

L. L. Klein & D. J. Klein (1977) Feeding behavior of the Colombian spider monkey, Ateles belzebuth. In: Primate ecology, ed. T. H. Clutton-Brock . Academic Press. [CHJ]

B. Knauft (1987) Reconsidering violence in simple human societies: Homicide among the Gebusi of New Guinea. Current Anthropology 28:457500. [aRIMD]

H. Kummer (1982) Social knowledge in free-ranging primates. In: Animal mind – human mind, ed. D. Griffin . Springer-Verlag. [aRIMD]

R. B. Lee (1992) Art, science, or politics? The crisis in hunter-gatherer studies. American Anthropologist 94:3154. [RJ]

R. F. Legget & T. D. Northwood (1960) Noise surveys of cocktail parties. Journal of the Acoustical Society of America 32:1618. [aRIMD]

B. B. Little (1989) Gestation length, metabolic rate, and body and brain weights in primates: Epigenetic effects. American Journal of Physical Anthropology 80:213–18. [IIG]

R. D. Luce & A. Perry (1949) The method of matrix analysis of group structure. Psychometrika 14:95116. [LCF]

M. Lynch (1991) Methods for the analysis of comparative data in evolutionary biology. Evolution 45:1065–80. [EPM]

W. P. Maddison (1990) A method for testing the correlated evolution of two binary characters: Are gains or losses concentrated on certain branches of a phylogenetic tree? Evolution 44:539–57. [EPM]

E. P. Martins & T. Garland Jr., (1991) Phylogenetic analyses of the correlated evolution of continuous characters: A simulation study. Evolution 45:534–57. [EPM]

A. R. Maryanski (1987) African ape social structure: Is there strength in weak ties? Social Networks 9:191215. [LCF]

N. Masataka & K. Fujita (1989) Vocal learning of Japanese and rhesus monkeys. Behaviour 109:191–99. [RJA]

C. R. Menzel (1991) Cognitive aspects of foraging in Japanese monkeys. Animal Behaviour 41:397402. [BJ]

C. Mitchell , S. Boinski & C. P. van Schaik (1991) Competitive regimes and female bonding in two species of squirrel monkeys (Saimiri oerstedi and S. sciurcus). Behavioral Ecology and Sociobiology 28:5560. [CHJ]

P. J. Morgane , I. I. Glezer & M. S. Jacobs (1988) Visual cortex of the dolphin: An image analysis study. Journal of Comparative Neurology 273:325. [BJ]

P. J. Morgane , M. S. Jacobs & A. Galaburda (1985) Conservative features of neocortical evolution in dolphin brain. Brain Behavior & Evolution 26:176–84. [BJ]

A. Mori (1977) The social organisation of the provisioned Japanese monkey troops which have extraordinarily large population sizes. Journal of the Anthropological Society. Nippon 85:325–45. [rRIMD, AHH]

R. Naroll (1956) A preliminary index of social development. American Anthropologist 58:687715. [aRIMD, HK]

E. L. Newport (1990) Maturational constraints on language learning. Cognitive Science 14:1128. [MCC]

M. J. Owren & R. Bernacki (1988) The acoustic features of vervet monkey (Cercopithcecus aethiops) alarm calls. Journal of the Acoustical Society of America 83:1927–35. [MH]

M. D. Pagel & P. H. Harvey (1988a) Recent developments in the analysis of comparative data. Quarterly Review of Biology 63:413–40.

M. D. Pagel & P. H. Harvey (1988b) The taxon-level problem in the evolution of mammalian brain size: Facts and artifacts. American Naturalist 132:344–59. [rRIMD]

M. D. Pagel & P. H. Harvey (1989) Comparative methods for examining adaptation depend on evolutionary models. Folia Primatologica 53:203–20. [RAB]

R. E. Passingham (1973) Anatomical differences between the cortex of man and other primates. Brain Behavior & Evolution 7:337–59. [DF]

R. E. Passingham (1975) Changes in the size and organization of the brain in man and his ancestors. Brain Behavior & Evolution 11:7390. [DF]

L. A. Pettito & P. F. Marentette (1991) Babbling in the manual mode: Evidence for the ontogeny of language. Science 251:1493–96. [MCC]

S. Pinker & P. Bloom (1990) Natural language and natural selection. Behavioral and Brain Sciences 13:585642. [rRIMD, MCC]

J. M. Plavcan & C. P. van Schaik (1992) Intrasexual competition and canine dimorphism in anthropoid primates. American Journal of Physical Anthropology 87:461–77. [DD]

L. W. Porter & E. E. Lawler (1965) Properties of organisation structure in relation to job attributes and job behaviour. Psychological Bulletin 64:2351. [aRIMD]

D. Price & D. Beaver (1966) Collaboration in an invisible college. American Psychologist 21:1011–18. [aRIMD]

M. J. Raleigh & M. T. McGuire (1989) Female influences on male dominance acquisition in captive vervet monkeys, Cercopithecus aethiops sabeaus. Animal Behaviour 38:5967. [BJ]

J. M. V. Rayner (1985) Linear relations in biomechanics: The statistics of scaling functions. Journal of Zoology (London) 206:415–39. [aRIMD, CHJ]

M. J. Renner & M. R. Rosenzweig (1987) Enriched and impoverished environments: Effects on brain and behavior. Springer-Verlag. [BJ]

B. Richman (1976) Some vocal distinctive features used by gelada monkeys. Journal of the Acoustical Society of America 60:718–24. [arRIMD, CTS]

B. Richman (1978) The synchronisation of voices by gelada monkeys. Primates 19:569–81. [arRIMD, MH, CTS]

B. Richman (1987) Rhythm and melody in gelada vocal exchanges. Primates 28:199223. [arRIMD, MH, CTS]

J. G. Robinson (1981) Vocal regulation of inter- and intragronp spacing during boundary encounters in the titi monkey, Callicehus moloch. Primates 22:161–72. [CTS]

L. Rodseth , R. W. Wrangham , A. M. Harrigan & B. B. Smuts (1991) The human community as a primate society. Current Anthropology 32:221–41. [MH]

T. E. Rowell & D. K. Olson (1983) Alternative mechanisms of social organization in monkeys. Behaviour 86:3154. [MC]

A. Roy , J. De Jong & M. Linnoila (1989) Cerebrospinal fluid monoarnine metabolites and suicidal behavior in depressed patients: A five year follow-up study. Archives of General Psychiatry 46:609–12. [BJ]

L. D. Sailer & S. J. C. Gaulin (1984) Proximity, sociality and observation: The definition of social groups. American Anthropologist 86:9198. [LCF]

T. Sawaguchi (1988) Correlations of cerebral indices for “extra” cortical parts and ecological variables in primates. Brain, Behavior & Evolution 32:129–40. [rRIMD]

T. Sawaguchi (1989) Relationships between cerebral indices for “extra” cortical parts and ecological categories in anthropoids. Brain Behavior & Evolution 34:281–93. [IIG]

T. Sawaguchi (1990) Relative brain size, stratification and social structure in anthropoids. Primates 31:257–72. [AHH, AW]

T. Sawaguchi (1992) The size of the neocortex in relation to ecology and social structure in monkeys and apes. Folia Primatologica 58:131–45. [IIG]

T. Sawaguchi & H. Kudo (1990) Neocortical development and social structure in primates. Primates 31:283–90. [arRIMD.AW]

M. D. Scott & S. J. Chivers (1990) Distribution and herd structure of bottlenose dolphins in the eastern tropical Pacific Ocean. In: The bottlenose dolphin, ed. S. Leatherwood & R. R. Reeves . Academic Press. [BJ]

M. Seidenberg & L. A. Pettito (1987) Communication, symbolic communication, and language: Comment on Savage-Rumbaugh, McDonald, Sevcik, Hopkins & Rupert (1986). Journal of Experimental Psychology: General 116:279–87. [MCC]

R. M. Seyfarth & D. L. Cheney (1984) Grooming, alliances and reciprocal altruism in vervet monkeys. Nature (London) 308:541–43. [aRIMD]

H. S. Sharp (1977) The Chipewyan hunting unit. American Ethnologist 4:377–93. [RJ]

H. J. Smith , J. D. Newman & D. Symmes (1982) Vocal concomitants of affiliative behavior in squirrel monkeys. In: Primate communication, ed. C. T. Snowdon , C. H. Brown & M. R. Petersen . Cambridge University Press. [CTS]

B. B. Smuts & J. M. Watanabe (1990) Social relationships and ritualized greetings in adult male baboons (Papio cynocephalus anubis). International Journal of Primatology 11(2):147–72. [MH]

C. T. Snowdon (1988) Communication as social interactions: Its importance in ontogeny and adult behavior. In: Primate vocal communication, ed. D. Todt , P. Goedeking & D. Symes . Springer-Verlag. [RMS]

C. T. Snowdon (1989) Vocal communication in New World monkeys. Journal of Human Evolution 18:611–33. [CTS]

C. T. Snowdon (1990) Language capacities of nonhuman animals. Yearbook of Physical Anthropology 33:215–43. [MH]

C. T. Snowdon & J. Cleveland (1984) “Conversations” among pygmy marmosets. American Journal of Primatology 7:1520. [CTS]

R. Sommer (1961) Leadership and group geometry. Sociometry 24:99110. [aRIMD]

H. Stephan , H. Frahm & G. Baron (1981) New and revised data on volumes of brain structures in insectivores and primates. Folia Primatologica 35:129. [aRIMD, RAB, DF, RLH, HJJ]

F. W. Terrien & D. L. Mills (1955) The effect of changing size upon the internal structure of organisations. American Sociological Review 20:1113. [aRIMD]

N. Tinbergen (1963) On the aims and methods of ethology. Zeitschrift für Tierpsychologie 20:410–33. [rRIMD]

P. V. Tobias (1981) The emergence of man in Africa and beyond. Philosophical Transactions of the Royal Society of London, Series B 292:4356. [DF]

P. V. Tobias (1987) The brain of Homo habilis: A new level of organization in cerebral evolution. Journal of Human Evolution 16:741–62. [RLH]

N. Toth (1985) Archeological evidence for preferential right-handedness in the Lower and Middle Pleistocene, and its possible implications. Journal of Human Evolution 14:607–14. [DF]

E. Trinkaus (1986) The Neandertals and modern human origins. Annual Review of Anthropology 15:193218. [MEH]

M. van Roosmalen (1985) Habitat preferences, diet, feeding strategy and social organization of the black spider monkey (Ateles paniscus paniscus Linnaeus 1758) in Surinam. Acta Amazonica (suppl.) 15:1238. [CHJ]

C. P. van Schaik (1982) Why are diurnal primates living in groups? Behaviour 87:120–44. [rRIMD]

C. P. van Schaik & R. I. M. Dunbar (1990) The evolution of monogamy in large primates: A new hypothesis and some crucial tests. Behaviour 115:3062. [rRIMD]

M. Virkkunen & M. Linnoila (1990) Serotonin in early male alcoholics with violent behavior. Annual of Medicine 22:327–31. [BJ]

W. von Rafller-Engel , J. Wind & A. Jonker , eds. (1991) Studies in language origins, vol. 2. Benjamins. [JW]

J. C. Webster (1965) Speech communications as limited by ambient noise. Journal of the Acoustical Society of America 37:692–99. [aRIM D]

D. S. Wilson (1989) Levels of selection: An alternative to individualism in biology and the social sciences. Social Networks 11:257–72. [LAD]

D. S. Wilson & E. Sober (1989) Reviving the superorganism. Journal of Theoretical Biology 136:337–56. [MEH]

R. W. Wrangham (1979) On the evolution of ape social systems. Social Science Information 18:335–68. [aRIMD]

R. W. Wrangham (1980) An ecological model of female kin-bonded groups. Behaviour 75:262300. [RAF]

B. Würsig (1989) Cetaceans. Science 244:1550–57. [BJ]

K. Zilles , E. Armstrong , K. H. Moser & H. Stephan (1989) Cyrification in the cerebral cortex of primates. Brain Behavior & Evolution 34:143–50. [DF]

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