A satisfactory account of human cognitive evolution will explain not only the psychological mechanisms that make our species unique, but also how, when, and why these traits evolved. To date, researchers have made substantial progress toward defining uniquely human aspects of cognition, but considerably less effort has been devoted to questions about the evolutionary processes through which these traits have arisen. In this article, I aim to link these complementary aims by synthesizing recent advances in our understanding of what makes human cognition unique, with theory and data regarding the processes of cognitive evolution. I review evidence that uniquely human cognition depends on synergism between both representational and motivational factors and is unlikely to be accounted for by changes to any singular cognitive system. I argue that, whereas no nonhuman animal possesses the full constellation of traits that define the human mind, homologies and analogies of critical aspects of human psychology can be found in diverse nonhuman taxa. I suggest that phylogenetic approaches to the study of animal cognition-which can address questions about the selective pressures and proximate mechanisms driving cognitive change-have the potential to yield important insights regarding the processes through which the human cognitive phenotype evolved.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2014. / In the present thesis the use of convergence as a tool in functional analyses was investigated, with special focus on comparisons using distantly related species (“convergence approach”). Guidelines for the convergence approach were forumlated and applied in the evaluation of selected hypotheses on the contextualization of early hominins. Additionally, comprehensive reviews on water use in primates were carried out, with special focus on hominoids, including humans. The first description (and video footage) of swimming and diving behaviour in a common chimpanzee (Pan troglodytes) and an orangutan (Pongo pygmaeus) were presented here, along with swimming behaviour in other great apes (without video footage). Hypotheses on the loss of instinctive swimming in hominoids were discussed and the Saci last common ancestor hypothesis was proposed. This model suggests that the loss of swimming ability in hominoids is best explained as a consequence of phylogenetic constraints linked to the adaptation to an arboreal life in the last common ancestor of this taxon. Furthermore, several hypotheses on early hominin evolution were reviewed. It was pointed out that several of these hypotheses have similar methodological flaws in the use of analogies to corroborate specific arguments. A hypothesis on the emergence of the habitual bipedalism in early hominins was outlined, arguing that this trait did not evolve in association with a locomotory advantage or for other reasons usually presented in the literature, but as a signal to advertise unprofitability – as a warning signal in an anti-predator strategy. It was argued that fossil evidence does not allow a high resolution of inference concerning incipient traits – traits which are not optimized to fulfil a certain function after a functional change. The consideration of different lines of evidence presented in this thesis indicate that the topic “water use” must be considered in discussions on early hominin evolution. The fact that humans regularly and intensively interact with water can be considered as an indication that in some part of human phylogeny after the hominin/panin split, swimming and diving ability was specifically selected. However, contrary to the view of several proponents of the aquatic hypotheses, it was demonstrated that humans are not absolutely unique concerning their ability to learn to swim and to dive. It is therefore also conceivable that our ability to learn to swim is associated to our cognitive abilities and is not a product of specific selection in our past.

This study examined the topography of prefrontal molds of human endocasts using three-dimensional laser scanning and geographic information systems (GIS) in order to carry out intra-species comparisons. Overall brain topography can indicate when major reorganizational shifts in brain structure happened in our evolutionalry history, and these shifts may indicate major shifts in cognition and behavior. Endocasts are one of the sole sources of information about extinct hominin brains ; they reproduce details of the brain's external morphology. Analysis of endocast morphology has never been done using GIS methodology. The use of GIS helps to overcome previous obstacles in regards to endocast analysis. Since this methodology is new, this research focuses on only one species, Homo sapiens and the area of focus is narrowed to the frontal lobe, specifically Broca's cap. This area is associated with speech in humans and is therefore of evolutionary significance. The variability in lateralization of this feature was quantified. / by Melissa Boas. / Thesis (M.A.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

The Paranthropus head is characterized by features traditionally thought to be related to heavy chewing. McCollum [Science 284 (1999) : 301-305] proposed that palatal thickening is a response to developmental integration between the mandibular ramus, oral and nasal functional matrices, and the vomer, which inserts onto the premaxilla in Paranthropus and causes the palate to thicken instead of rotate during vertical expansion. I tested whether palate thickness increases as a byproduct of differential increases in the sizes of the oral and nasal functional matrices compared to growth in the mandibular ramus. To do so, I collected 3D volume and landmark data from computed tomography (CT) scans of extant (Homo sapiens, Pan troglodytes, Gorilla gorilla, Pongo pygmaeus) and extinct taxa (Australopithecus and Paranthropus), and tested counterpart relationships for bones in the cranium using scaling analyses. Results suggest that developmental constraints related to growth counterpart relationships in the skulll are unlikely to affect palate thickness in the genus Paranthropus. / by Brittany A. Burdelsky. / Thesis (M.A.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

The timing of skeletal growth spurts in modern humans is unique among mammals. In modern humans, peak growth occurs after puberty during the adolescent period, whereas large-bodied non-human primates exhibit an earlier juvenile growth spurt. Based on limited data, previous researchers have suggested that Neanderthals experienced a late, modern human-like adolescent growth spurt. In this study, I examined the timing of stature and facial growth spurts in Neanderthals to test the hypothesis that Neanderthals grew like modern humans. In order to assess the timing of Neanderthal growth spurts, I plotted a non-human primate regression estimate of age at puberty onto Neanderthal stature and mandibular velocity growth curves. The mandibular growth curve exhibits a discernible growth spurt after puberty, reminiscent of the modern human adolescent growth spurt. Future research on additional regions of the skeleton is necessary to further refine this estimate for the timing of Neanderthal growth spurts. / by Amy C. Lupo. / Thesis (M.A.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

This thesis presents a model of a narrow faculty for music - qualities that are at once universally present and operational in music across cultures whilst also being specific to our species and to the domain of music. The comparative approach taken focuses on core psychological and physiological capabilities that root and enable appropriate engagement with music rather than on their observable physical correlates. Configurations of musical pulse; musical tone; and musical motivation are described as providing a sustained attentional structure for managing personal experience and interpersonal interaction and as offering a continually renewing phenomenological link between the immediate past, the perceptual present and future expectation. Constituent parts of the narrow faculty for music are considered most fundamentally as a potentiating, quasi-architectural framework in which our most central affective and socio-intentional drives are afforded extended time, stability, and a degree of abstraction, intensity, focus and meaning. The author contends, therefore, that music's defining characteristics, specific functionalities and/or situated efficacies are not demarcated in broadly termed "musical" qualities such as melodic contour or rhythm or in those surprisingly elusive "objective facts" of musical structure. Rather they are solely the attentional/motivational frameworks which root our faculty to make and make sense of music. Our generic capacities for culture and the manifold uses of action, gesture, and sound to express and induce emotion; to regulate affective states; to create or reflect meaning; to signify; to ritualize; coordinate; communicate; interrelate; embody; entrain; and/or intentionalize, none of these is assessed as being intrinsically unique to music performance. Music is, instead, viewed as an ordered expression of human experience, behaviour, interaction, and vitality, all shaped, shared, given significance, and/or transformed in time. The relevance of this model to topical debates on music and evolution is discussed and the author contends that the perspective offered affords significant implications for our understanding of why music is evidently and remarkably effective in certain settings and in the pursuit of certain social, individual, and therapeutic goals.

<p>There has been a trend toward decreasing skeletal robusticity in the genus Homo throughout the Pleistocene, culminating in the gracile postcrania of living modern humans. This change is typically attributed to changing tool technologies and subsistence patterns among human groups. However, other mammalian groups also experience a similar change in their postcranial strength over the same time period. It is proposed in this dissertation that ecological variables are correlated with measures of postcranial strength and may be a better explanation for Holocene skeletal gracilization in humans, as well as in other mammalian genera. This hypothesis is investigated through a close examination of the scaling patterns in two extant genera, Canis and Ursus, and a comparison of scaling patterns and relative strength of different species of Canis, including a fossil species that provides information about temporal change. Measurements of limb length, joint surface area, bone diameter, and strength measurements derived from radiographic images of long bone midshafts of North American specimens of Canis, (including the fossil Canis dirus) and Ursus were collected. Scaling patterns of the cross-sectional variables on limb length and joint surfaces were analyzed for the interspecific and intraspecific samples. </p><p>The first hypothesis tested was that Canis scales with geometric similarity of cross-sectional variables on bone length and body mass, and the Ursus scales with elastic similarity. Larger Canis have relatively stronger postcrania than smaller Canis. The primary way in which this strength is achieved in larger individuals is through a relatively shortening of the bone length. The second hypothesis tested was that postcranial strength is correlated with ecological variables. To investigate this hypothesis, scaling patterns of different species of Canis were compared, including the fossil dire wolf. The results show that the dire wolf is relatively stronger than its living congenerics. There is also a strong relationship between the ratio of prey body mass to predator body mass and relative strength for these species. Carnivores that are hunting animals much larger than themselves must have postcranial skeletons that are strong enough to withstand the loading of the skeleton that occurs during hunting, taking down, and processing large herbivores.</p> / Dissertation

This dissertation provides a comprehensive and systematic examination of anthropoid primate milk composition and its relationship to a species' evolutionary history, ecological context, and life history strategy. Milk samples from 14 species of anthropoid primate (Alouatta paliatta, Callithrix jacchus, Cebus apella, Gorilla beringei beringei, Gorilla gorilla gorilla, Hylobates lar, Leontopithecus rosalia, Macaca mulatta, Macaca sinica, Pan paniscus, Pan troglodytes, Pongo pygmaeus, Saimiri boliviensis boliviensis, and Symphalangus syndactylus) were analyzed for proximate composition (fat, protein, lactose, dry matter, and minerals) and milk fatty acid composition. The objectives of this study were identification of primitive features in anthropoid milks, shared-derived features of anthropoid families or superfamilies, and unique-derived features of species, including Homo sapiens.Results did not support the null hypothesis of a generalized anthropoid milk composition. Variation among anthropoids in milk fatty acid profiles and proximate milk composition was influenced by phylogeny and the life history strategy of the species, as well as the diet and environment (captive or wild living) of the mother.Maternal diet had a direct influence on fatty acid profiles and created distinct groupings of wild and captive living individuals. Phylogenetic patterns were identified within captive and wild groups, particularly a distinction between milk fatty acid profiles of hominoids (including humans) and monkeys.Significant variation in proximate milk composition was identified at the level of the superfamily. Cercopithecoid milk was highest in mean fat, dry matter, the proportion of energy from fat, and total gross energy. Ceboid milk was highest in mean protein and the proportion of energy from protein. Hominoid milks were lowest in mean fat, protein, dry matter, the proportion of energy from fat, and total gross energy.Hominoid milk also was lowest in the degree of plasticity in milk composition. Milk of captive living monkeys was higher than milk of wild living monkeys in mean fat, percent energy from fat, and total gross energy. Milk fat and energy also were highly variable within captive living monkeys. In contrast, fat and total gross energy were not significantly different between captive and wild living hominoids and were less variabile among captive living hominoids as compared to monkeys. The lack of variability and the relatively low energy values in hominoid milk suggest that it may be buffered against environmental fluctations. Larger body size and a longer duration of lactation may permit hominoids, including humans, to decouple maternal condition from milk energy and instead relying on energy storage.

No description available.

This dissertation describes the technological behaviors represented by the ~500-thousand-year-old stratum 4a lithic assemblage from Kathu Pan 1 (KP1), Northern Cape, South Africa, and situates new evidence from this site into evolutionary context. The findings highlight the significance of the early Middle Pleistocene in Africa for understanding behavioral evolution in later Homo. The stratum 4a assemblage at KP1 represents a mainly flake and blade-based industry that employed multiple strategies to produce blanks that were retouched into a variety of forms, including unifacially retouched points. Diverse core reduction strategies at KP1 suggests that KP1 hominins were flexible to the demands of local raw materials, consistent with increased degrees of ‘behavioral variability’ and adaptability. Several lines of evidence indicate that the KP1 points were used as spear tips. Points from sites ~300 thousand years ago (ka) and younger were often used as weapon tips, and evidence for this behavior can now be pushed back to ~500 ka, with important implications for cognition and social behavior among early Middle Pleistocene hominins. Raw materials in the KP1 assemblage were acquired from multiple local sources. Based on comparisons with a sample from the underlying stratum 4b Acheulean assemblage, the stratum 4a assemblage does not exhibit major changes in the kinds or quality of raw material exploited; thus, the technological changes represented by the stratum 4a assemblage are not explained by changes in raw material. New evidence from KP1 poses problems for current models that link the appearance of Middle Stone Age technologies to speciation and dispersion ~300 ka. Middle Stone Age technologies appear in the African archaeological record by ~500 ka. The new timing for the origins of Middle Stone Age technologies provides a parsimonious explanation for technological similarities between the lithic assemblages of Neanderthals and modern Homo sapiens, who share a common ancestor in the early Middle Pleistocene. Limits imposed by the nature of the African archaeological record and chronometric analyses may explain why the antiquity of these technological changes was not previously recognized.