The neuroethological basis of social signals was investigated using a multidisciplinary approach, involving connectional and comparative analysis of anatomical data, single cell recording and behavioural techniques. Previous literature implicates the amygdala, anterior temporal and prefrontal cortex in primate social functions. Non-metric multidimensional scaling (NMDS) and cluster analysis were used to analyse the connectional relatedness of macaque cortico-cortical and amygdalo-cortical connections. This objective analysis separated the amygdala nuclei into two groups, the basolateral (BL) and centromedial (CM) complexes. A comparative analysis was made of the possible functions of the amygdala nuclei by correlating amygdala nuclear volume with 5 socio-ecological indices, across 44 primate species. The lateral basal (LB) nucleus and BL size was found to correlate positively with social complexity. CM size correlated negatively. The LB nucleus receives information from the STS, which contains visual neurons responsive to eyes, heads and bodies. These cells were assessed for coding of socially relevant information. Single cell recording localised within the macaque superior temporal sulcus (STS) revealed neurons responsive to specific views, elevations and orientations of the head, eye position, and specific views of bodies walking in specific directions and reaching to objects. The tuning of these neurons could therefore support the function of recognition of another's purposive behaviour (e.g. direction of attention or intention). Visually responsive neurons in the STS also differentiated faces of different species (i.e. monkeys, humans and other animals). Behavioural studies suggest that monkeys do not follow the direction of attention of humans, yet monkeys appear to have the neural capacity. A behavioural study using video stimuli, revealed that monkeys spontaneously follow other monkeys' gaze onto an object or point in space. It is concluded that the amygdala and STS are part of a neural system which enable monkeys to interpret another's gaze and actions within a purposive behavioural framework.

Most people assume that monkeys and apes can imitate, but recently, several researchers have suggested there is little convincing evidence of imitation in any nonhuman species. The purpose of the present thesis is to compare the imitative abilities of human and non-human primates. Some of the most convincing evidence for imitation comes from anecdotal reports of imitative behaviour in great apes. A survey of the literature was performed and a database of imitative episodes in chimpanzees, gorillas and orangutans was compiled (using a similar approach to Whiten & Byrne's 1988a tactical deception database). Each report was subjected to a strict evaluation, and it was deemed that 23 reports from chimpanzees, 3 from gorillas and 4 from orangutans provided relatively convincing evidence of imitation. An experiment was conducted to test if chimpanzees can imitate as the anecdotal data suggests. Two chimpanzees were taught to reproduce 15 arbitrary gestures on the command "Do this". Next they were presented with 48 novel items. They imitated 13 and 20 novel gestures respectively. Using a rigorous coding system, two independent observers correctly identified a significant number of the chimpanzees' imitations (P< 0.0001). These results show that chimpanzees are capable of the complex intermodal visual-motor co-ordination and control necessary for imitation. The second experimental chapter explores whether monkeys, apes, and/or humans imitate in the context of a functional task. Six capuchin monkeys (Cebus apella), eight chimpanzees (Pan troglodytes) and 24 children were presented with an analogue of a natural food processing task. The subjects were divided into two groups and each saw a different method for opening an artificial fruit. The children showed quite extensive imitation; the capuchin monkeys showed little to none; while the chimpanzees showed marginal imitative abilities. This constitutes the first experimental evidence of functional object imitation in a nonhuman specie.

No description available.

No description available.

A full understanding of any biological trait requires investigation of its evolutionary origin. Primates inspire great curiosity amongst researchers due to the remarkable diversity across species in both anatomical and behavioural traits, including sociality, sexual behaviour, life histories, neuro-anatomy, cognitive abilities and behavioural repertoires. The study of primates has involved comparative approaches since its inception, however, the necessary tools for statistically investigating the macro-evolutionary processes responsible for current diversity in biological traits have been developed only in the last 30 years or so, namely phylogenetic reconstruction and phylogenetic comparative methods. Amongst a multitude of evolutionary questions that can be addressed by phylogenetic comparative analyses, this thesis attempts to address two in particular, concerning primates. First, chapters 3 and 4 use meta-analysis and phylogenetic comparative analyses to investigate the evolution of large, brightly coloured ‘exaggerated sexual swellings' in female Catarrhine (‘Old World') primates. Together, chapters 3 and 4 show that such swellings are signals of temporal fertility, and present evidence to suggest that swellings co-evolved with conditions favouring male mate choice and cryptic female choice, therefore shedding light on the general conditions under which female signals of temporal fertility should evolve. Second, chapters 5 and 6 use phylogenetic comparative analyses investigate the evolution of enlarged brain size in the primate order. Together, chapters 5 and 6 suggest that multiple selection pressures have contributed to diversity in brain size and cognitive traits across primates, including sociality, intra-sexual competition and extended life history. Further, analyses presented in chapter 6 suggest that reliance on learned behaviour is a self-reinforcing evolutionary process, favouring ‘runaway' increases in cognitive abilities and reliance on culture in some primate lineages, which parallels increases in brain size, cognitive ability and reliance on culture in human evolution.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, infulfilment of the requirements for the .degree Doctor of Philosophy Johannesburg ' 1989

This study investigates how anthropomorphism arises in Western and Japanese reports of non-human primate behaviour. Chapter 1 introduces the study and notes that differences in recording styles and incidence of anthropomorphism in Western and Japanese reports led to the thesis that the basis for anthropomorphism differed between the two groups. In Western studies it was found necessary to inquire into philosophical aspects of language use. In Japanese studies the inquiry centred on evidence for the retention of traditional attitudes to nature. Part One focuses on the basis for anthropomorphism in Western studies. Chapter 2 discusses the intellectual basis for the deeply ingrained belief in the West in the separateness of man and animals. The more immediate intellectual background to Western primate studies is traced in chapter 3 through the development of comparative psychology and ethology and then of primatology itself. A more precise formulation of the Western inquiry is developed in chapter h through discussion of ordinary language, distinction between categories of anthropomorphism and between the notions of a subjective approach to study and the ascription of human subjective experiences to animals. Cognitive ethology is briefly described. Chapter 5> identifies the characteristic of language use that gives rise to anthropomorphism as metaphor. Part Two focuses on Japanese studies. Japan had no tradition of objective science and Western science was imported to Japan. This section develops the argument that Western science was adapted to existing Japanese thought and that a traditional intuitive approach to nature and feeling of unity with animals was retained. The development of Japanese primate studies and evidence for the acceptability of anthropomorphism to Japanese primatologists are presented in chapter 6. Certain basic ideas of traditional Japanese views are outlined in chapter 7. The effects of the first small-scale importation of Western science on the Neo-Confucian precepts of Tokugawa Japan are traced in chapter 8. The way in which especially biology was understood in the subsequent major importation of science to Meiji Japan is examined in chapter 9. The methodology of the Japanese primatologists is examined in chapter 10 and newly translated material showing the application of traditional Japanese thought to primatology is presented. Other new material on the origins of the focus on personality and culture in monkey groups is given. The application of traditional Japanese ideas of nature to their methodology and the use of a socioanthropological framework for explanation of observed behaviour is seen to be compatible with anthropomorphism in the Japanese studies. Chapter 11 summarizes the course of the study and discusses what conclusions may be drawn.

The following study was conducted from August to November of 1991 on North Pagai Island in the Mentawai Archipelago, Indonesia. The purpose of the study was to obtain preliminary information on the ecology and behavior of the four Mentawai endemic primates: Hylobatcs klossii, Macaca pagensis, Presbytis potenziani, and Simias concolor. All four species are considered endangered due to human activities, especially hunting and various forms of habitat destruction. Therefore, the present critical status of these primates makes their conservation and that of the Mentawai Islands' rain forest a priority. It appears that resource partitioning occurs among the four primate species, M. pagensis occupied all vegetation levels and was less arboreal relative to the other three species which were primarily arboreal. All four species were found in forest habitat with S. concolor also occurring in forest swamp. M. pagensis and P. potenziani were found throughout the study area and only P. potenziani occupied coastal swamp. In addition, it is hypothesized here that for many P. potenziani groups, sleeping trees are located outside of the primary forest and these groups migrate on a daily basis to the forest. As a result, this may reduce interspecific competition since this species and H. klossii overlap in terms of resource use. Group size and composition are discussed and a monogamous social organization was identified for H. klossii and P. potenziani while M. pagensis. was found to form polygamous families. S. concolor is identified as forming one-male polygamous groups, however, based on my observations it might initially be interpreted that this species formed monogamous groups in the study area. Most behaviors, such as parental care, aggression, grooming, play, and feeding behavior, were rarely observed due to the wanness of these primates. Alarm response to detection of humans is discussed and distraction-like behaviors are described for each of the species. Population density was determined for each species and these values corresponded to those found in other studies although all values in this study were relatively low compared to other studies.

The following research paper was concerned with five basic objectives:(1) outlining the major theoretical and methodological approaches used in the reconstruction of early hominid social behavior/social structure as a context in which to view Richard Wrangham's and Michael Ghiglieri's phylogenetic models of stem-hominid social structure.(2) examining Wrangham's and Ghiglieri's models of stem-hominid and chimpanzee social structure.(3) indicating how theoretical and methodological aspects of structure essentially represent an extension of the theoretical and methodological approaches the same researchers applied to their models of chimpanzee social structure.(4) addressing the theoretical and methodological deficiences of Wrangham's and Ghiglieri's models of chimpanzee social structure.(5) providing suggestions for improved phylogenetic models of early hominid social structure.The first objective was achieved by: (a) reviewing Tooby and Devore's (1986) and Wrangham's (1986) evaluations of the major theoretical approaches and methodologies used in the reconstruction of hominid social behavior/structure (b) defining, classifying and evaluating Wrangham's and Ghiglieri's phylogenetic approaches within this context.The second objective was accomplished by outlining, analyzing, and comparing/contrasting Wrangham's and Ghiglieri's phylogenetic models of stem-hominid social structure (i.e.Wrangham 1986; Ghiglieri 1987, 1989) and Wrangham's and Ghiglieri's models of chimpanzee social structure (i.e. Wrangham 1975, 1979; Ghiglieri 1984, 1985, 1987, 1989).The third objective was achieved by recognizing how Wrangham and Ghiglieri used/stressed principles and concepts derived from evolutionary biology and/or behavioral ecology to develop their models of stem-hominid and chimpanzee social structure. This analysis showed that Wrangham's models of social structure were more favorably inclined toward the method of behavioral ecology than Ghiglieri's models, which favored a sociobiological paradigm. Furthermore, although neither researcher relied exclusively on the above theoretical approaches, the main thrust of their argument often centered around it. For instance, Wrangham's analysis of chimpanzee social structure (Wrangham 1975, 1979) indicated that the ultimate cause of that structure was ecological i.e., patchy food distribution leads to wide female dispersal for optimal foraging efficiency, which in turn favors a male kin breeding group that can maintain a territority that includes several individual female ranges. In contrast, Wrangham's phylogenetic model of the social structure of the stem-hominid (Wrangham, 1986) suggested that phylogenetic inertia may be partially responsible for the shared social features found among African Hominoidea. However, in the same work, Wrangham also suggested that further socioecological analysis of African apes may indicate whether food distribution and its effects on female dispersion/association may partially explain conservative African ape social features.Ghiglieri's phylogenetic model of the stem-hominid (1987, 1989), on the other hand, explained the conservative social features of bonobos, common chimpanzees, and hominids to be primarily a product of phylogenetic inertia and sexual selection. Furthermore, for Ghiglieri the most important sexual selection variable was a male communal reproductive strategy. This, according to Ghiglieri, is the ultimate cause of social structure. Notably, Ghiglieri (1984, 1985) had earlier stressed the overiding importance of a male communal reproductive strategy but was less dogmatic in his insistence that chimpanzees had essentially solved their ecological problems (e.g. that they had solved the food distribution problem by fusion-fission sociality; predators were never a real problem). Nevertheless, Ghiglieri's earlier position similarily expressed the idea that a communal reproductive strategy constituted the ultimate cause of social structure.The fourth objective was accomplished by presentation of an alternative model of chimpanzee social behavior which suggested that structure; the effect of phylogenetic inertia on social structure; chimpanzee social structure is the combined product of ecological and sexual selection forces: female optimal foraging, male mating strategies, and predator pressure. The model was considered by the author to be unique in that it integrated essential aspects of both Wrangham's and Ghiglieri's models and, in addition, provided support for Alexander's (1974) contention that predation pressure is an ultimate cause of ape social structure. The model also outlined scenarios for the evolution of chimpanzee group._ extensibility (fusion-fission sociality) and the capacity for warfare among chimpanzees.The last objective was achieved by a discussion of the implications that the author's model had for phylogenetic models of stem-hominid social structure. In this discussion the author reviewed the following issues as they related to the phylogenetic reconstruction of hominid social structure: the role of phylogeny and/or ecology in the causation of social encountered when using a phylogenetic referential model for the personal biases that enter into phylogenetic econstructions; pitfalls reconstruction of early hominid social evolution; the significance of chimpanzee models of social structure.The importance of the preceding study lay in its ability to stimulate improved conceptual models of African hominoid social structure. / Department of Anthropology

Self-directed behaviours (SDB) were recorded as a behavioural indicator of arousal in free-ranging vervet monkeys (Chlorocebus aethiops) inhabiting the Klein Karoo of South Africa. Measurement of SDB allowed for changes in arousal to be correlated with particular social situations, potentially providing insight into how monkeys perceive their social world. The research presented here is divided into three core chapters demonstrating that 1) arousal is influenced to a greater extent by degree of association than by hierarchical rank, 2) that an individual‟s level of arousal is influenced by its neighbour‟s spatial location, and 3) that habituated animals that no longer perceive humans as a direct threat nevertheless continue to respond to their presence in other ways. Overall, SDB appears to be a useful, non-invasive, simple means of investigating social arousal and its use has elucidated several key findings regarding the perception of social space and social partners in vervet monkeys. / ix, 103 leaves ; 28 cm