1,088 research outputs found

    Can the Archaeology of Manual Specialization Tell Us Anything About Language Evolution? A Survey of the State of Play

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    In this review and position paper we explore the neural substrates for manual specialization and their possible connection with language and speech. We focus on two contrasting hypotheses of the origins of language and manual specialization: the language-first scenario and the tool-use-first scenario. Each one makes specific predictions about hand-use in non-human primates, as well as about the necessity of an association between speech adaptations and population-level right-handedness in the archaeological and fossil records. The concept of handedness is reformulated for archaeologists in terms of manual role specialization, using Guiard's model asymmetric bimanual coordination. This focuses our attention on skilled bimanual tasks in which both upper limbs play complementary roles. We review work eliciting non-human primate hand preferences in co-ordinated bimanual tasks, and relevant archaeological data for estimating the presence or absence of a population-level bias to the right hand as the manipulator in extinct hominin species and in the early prehistory of our own species

    The evolutionary neuroscience of tool making

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    The appearance of the first intentionally modified stone tools over 2.5 million years ago marked a watershed in human evolutionary history, expanding the human adaptive niche and initiating a trend of technological elaboration that continues to the present day. However, the cognitive foundations of this behavioral revolution remain controversial, as do its implications for the nature and evolution of modern human technological abilities. Here we shed new light on the neural and evolutionary foundations of human tool making skill by presenting functional brain imaging data from six inexperienced subjects learning to make stone tools of the kind found in the earliest archaeological record. Functional imaging of this complex, naturalistic task was accomplished through positron emission tomography with the slowly decaying radiological tracer (18)flouro-2-deoxyglucose. Results show that simple stone tool making is supported by a mosaic of primitive and derived parietofrontal perceptual-motor systems, including recently identified human specializations for representation of the central visual field and perception of three-dimensional form from motion. In the naive tool makers reported here, no activation was observed in prefrontal executive cortices associated with strategic action planning or in inferior parietal cortex thought to play a role in the representation of everyday tool use skills. We conclude that uniquely human capacities for sensorimotor adaptation and affordance perception, rather than abstract conceptualization and planning, were central factors in the initial stages of human technological evolution. The appearance of the first intentionally modified stone tools over 2.5 million years ago marked a watershed in human evolutionary history, expanding the human adaptive niche and initiating a trend of technological elaboration that continues to the present day. However, the cognitive foundations of this behavioral revolution remain controversial, as do its implications for the nature and evolution of modern human technological abilities. Here we shed new light on the neural and evolutionary foundations of human tool making skill by presenting functional brain imaging data from six inexperienced subjects learning to make stone tools of the kind found in the earliest archaeological record. Functional imaging of this complex, naturalistic task was accomplished through positron emission tomography with the slowly decaying radiological tracer (18)flouro-2-deoxyglucose. Results show that simple stone tool making is supported by a mosaic of primitive and derived parietofrontal perceptual-motor systems, including recently identified human specializations for representation of the central visual field and perception of three-dimensional form from motion. In the naive tool makers reported here, no activation was observed in prefrontal executive cortices associated with strategic action planning or in inferior parietal cortex thought to play a role in the representation of everyday tool use skills. We conclude that uniquely human capacities for sensorimotor adaptation and affordance perception, rather than abstract conceptualization and planning, were central factors in the initial stages of human technological evolution

    Respiratory, postural and spatio-kinetic motor stabilization, internal models, top-down timed motor coordination and expanded cerebello-cerebral circuitry: a review

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    Human dexterity, bipedality, and song/speech vocalization in Homo are reviewed within a motor evolution perspective in regard to 

(i) brain expansion in cerebello-cerebral circuitry, 
(ii) enhanced predictive internal modeling of body kinematics, body kinetics and action organization, 
(iii) motor mastery due to prolonged practice, 
(iv) task-determined top-down, and accurately timed feedforward motor adjustment of multiple-body/artifact elements, and 
(v) reduction in automatic preflex/spinal reflex mechanisms that would otherwise restrict such top-down processes. 

Dual-task interference and developmental neuroimaging research argues that such internal modeling based motor capabilities are concomitant with the evolution of 
(vi) enhanced attentional, executive function and other high-level cognitive processes, and that 
(vii) these provide dexterity, bipedality and vocalization with effector nonspecific neural resources. 

The possibility is also raised that such neural resources could 
(viii) underlie human internal model based nonmotor cognitions. 
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    Making tools and making sense: complex, intentional behaviour in human evolution

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    Stone tool-making is an ancient and prototypically human skill characterized by multiple levels of intentional organization. In a formal sense, it displays surprising similarities to the multi-level organization of human language. Recent functional brain imaging studies of stone tool-making similarly demonstrate overlap with neural circuits involved in language processing. These observations consistent with the hypothesis that language and tool-making share key requirements for the construction of hierarchically structured action sequences and evolved together in a mutually reinforcing way

    The Proceduralization of Hominin Knapping Skill: Memorizing Different Lithic Technologies

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    Reconstructing the technical and cognitive abilities of past hominins requires an understanding of how skills like stone toolmaking were learned and transmitted. We ask how much of the variability in the uptake of knapping skill is due to the characteristics of the knapping sequences themselves? Fundamental to skill acquisition is proceduralization, the process whereby skilful tasks are converted from declarative memories (consciously memorized facts and events) into procedural memories (sub-consciously memorized actions) via repetitive practice. From knapping footage, we time and encode each action involved in discoidal, handaxe, Levallois and prismatic blade production. The structure and complexity of these reduction sequences were quantified using k-mer analysis and Markov chains. The amount of time spent on tasks and the pattern of core rotations revealed portions of these reduction sequences that are predisposed to being converted into procedural memories. We observed two major pathways to achieve this proceduralization: either a repetitive or a predictable sequence of core rotations. Later Acheulean handaxes and Levallois knapping involved a predictable platform selection sequence, while prismatic blade knapping involved a repetitive exploitation of platforms. Technologies and the portions of their reduction sequence that lend themselves to proceduralization probably facilitated the more rapid uptake of stone toolmaking skill

    The skill spectrum: methods for identifying variable skill-levels amongst handaxe-making hominins in the Middle Pleistocene

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    Handaxes are bifacial stone cutting tools that were made by hominins between circa 1.75 and 0.2 million years ago. They represent a significant advancement in stone-tool technology and a pivotal development in hominin cognition and behaviour. Experimental research suggests learning to make handaxes demands considerable repeated practice over time and social support mechanisms that encourage skill development. Considerable debate exists regarding whether guidance for learners in the Acheulean included verbal and/or gestural instruction, or neophytes learned solely through imitation/emulation. Whatever the mode of transmission, consistency in intra-assemblage biface morphology and manufacturing techniques implies normative standards for acceptable performance were maintained, even with resharpening, at sites like Gouzeaucourt (the focus of this thesis). Assemblages like this, where knappers shared common goals, permit the identification of the varying ability of individuals to adhere to such objectives. Additionally, because mastery of handaxe manufacture requires extensive training, it follows that a spectrum of skill should be visible in the archaeological record through analysing the bifaces that remain. Nonetheless, few studies have applied experimental outcomes directly to interpreting archaeological bifaces and the differences in skill-level they exhibit. It is this lacuna in Acheulean research that is addressed here. My results show that the quantitative and qualitative methodology I employ allows accurate differentiation between skilled and unskilled experimental knappers and, as such, helps to categorise archaeological bifaces according to the perceived skill-level of their maker. I have thus presented an original approach to collecting data from bifaces regarding previously unknown aspects of the hominins that made them. This information can be used to calculate the proportion of skill-levels contributing to an assemblage, thus providing more inventive ways of interpreting Palaeolithic sites. Consequently, I thereby anticipate that this thesis represents a prospective starting point for further experimental investigations into differentiating between skill-levels in the Acheulean

    Early knapping techniques do not necessitate cultural transmission

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    Early stone tool production, or knapping, techniques are claimed to be the earliest evidence for cultural transmis-sion in the human lineage. Previous experimental studies have trained human participants to knap in conditions involving opportunities for cultural transmission. Subsequent knapping was then interpreted as evidence for a necessity of the provided cultural transmission opportunities for these techniques. However, a valid necessity claim requires showing that individual learning alone cannot lead to early knapping techniques. Here, we tested human participants (N = 28) in cultural isolation for the individual learning of early knapping techniques by providing them with relevant raw materials and a puzzle task as motivation. Twenty-five participants were technique naïve according to posttest questionnaires, yet they individually learned early knapping techniques, therewith producing and using core and flake tools. Early knapping techniques thus do not necessitate cultural transmission of know-how and could likewise have been individually derived among premodern hominins

    Learning From Stone: Using Lithic Artifacts to Explore the Transmission of Culture at Bridge River, British Columbia

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    Inherent in all tool-making traditions is the necessity of teaching the next generation of toolmakers. The learning process, although crucial to our understanding of past societies, is difficult to study archaeologically, due to its intangibility. However, some technologies leave visible traces of their production. Key among these are chipped stone tools, known as lithics, which leave distinct archaeological traces of each part of the creation processes. Modern experimenters have recreated these processes, and as a result, have revealed archaeologically-visible differences between novice and expert knappers. These can be identified in archaeological lithic assemblages, and serve as a starting point for identifying the potential presence of novice knappers at archaeological sites. The Bridge River site, a pithouse village site in British Columbia, has yielded a collection of stone projectile points ranging from expertly crafted to crude and unfinished. Using these projectile points, this project seeks to piece together the social context within which novice toolmakers learned to knap. In order to do so, the project examines the points themselves, but also places them in the context of ethnographic depictions of the St’át’imc, the village’s builders and inhabitants, and of the broader literature on craft learning. From these three lines of evidence, a model of the transmission process at the Bridge River village is suggested, one dominated by an informal, perhaps observation-based learning environment
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