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Le Touquet – Paris-Plage, France

Rein R.,German Sport University Cologne | Bril B.,Groupe de Recherche Apprentissage et Contexte | Nonaka T.,Kibi International University
American Journal of Physical Anthropology | Year: 2013

Stone tool-use and manufacture is seen as an important skill during the evolution of our species and recently there has been increased interest in the understanding of perceptual-motor abilities underlying this skill. This study provides further information with respect to the motor strategies used during stone knapping. Kinematics of the striking arm were recorded in expert and novice knappers while producing flakes of two different sizes. Using Uncontrolled Manifold Analysis, the results showed that knappers structure joint angle movements such that the hammer trajectory variability is minimized across trials, with experts displaying significantly smaller variability compared with novices. Principal component analysis further revealed that a single component captures the complexity of the strike and that the strike is governed by movements of the elbow and the wrist. Analysis of movement velocities indicated that both groups adjusted movement velocities according to flake size although experts used smaller hammer, wrist, and elbow velocities in both flake conditions compared with novices. The results suggest that while the gross striking movement is easy to replicate for a novice knapper, it requires prolonged training before a knapper becomes attuned to the finer details necessary for controlled flaking. © 2013 Wiley Periodicals, Inc.

Rein R.,German Sport University Cologne | Nonaka T.,Kobe University | Bril B.,Groupe de Recherche Apprentissage et Contexte
PLoS ONE | Year: 2014

The earliest direct evidence for tool-use by our ancestors are 2.6 million year old stone tools from Africa. These earliest artifacts show that, already, early hominins had developed the required advanced movement skills and cognitive capacities to manufacture stone tools. Currently, it is not well understood, however, which specific movement skills are required for successful stone knapping and accordingly it is unknown how these skills emerged during early hominin evolution. In particular, it is not clear which striking movements are indicative of skilled performance, how striking movement patterns vary with task and environmental constraints, and how movement patterns are passed on within social groups. The present study addresses these questions by investigating striking movement patterns and striking variability in 18 modern stone knappers (nine experienced and nine novices). The results suggest that no single movement pattern characterizes successful stone knapping. Participants showed large inter-individual movement variability of the elementary knapping action irrespective of knapping experience and knapping performance. Changes in task- and environmental constraints led knappers to adapt their elementary striking actions using a combination of individual and common strategies. Investigation of striking pattern similarities within social groups showed only partial overlap of striking patterns across related individuals. The results therefore suggest that striking movement patterns in modern stone knappers are largely specific to the individual and movement variability is not indicative of knapping performance. The implications of these results for the development of percussive traditions are discussed. © 2014 Rein et al.

Nonaka T.,Kibi International University | Bril B.,Groupe de Recherche Apprentissage et Contexte
Human Movement Science | Year: 2012

In human manual activities, the two hands are often engaged in differentiated roles while cooperating with each other to produce an integrated outcome. Using recurrence methods, we studied the asymmetric bimanual action involved in stone bead production by craftsmen of different skill levels, and examined (a) how the control of unilateral movement is embedded in that of a bimanual system, and (b) how the behavior of a bimanual system is embedded in the context of the function performed in the world. Evidence was found that the movements of the two hands of experts were functionally linked, reflecting the roles assumed by each hand. We further found that only the dynamics of bimanual coordination of experts differentiated the functional requirements of different sub-goals. These results suggest that expertise in this skilled bimanual action lies in the nesting of functionally specific adjustments at different levels of a control hierarchy. © 2010 Elsevier B.V.

Rein R.,Groupe de Recherche Apprentissage et Contexte | Button C.,University of Otago | Davids K.,Queensland University of Technology | Summers J.,University of Tasmania
Motor Control | Year: 2010

The present paper proposes a technical analysis method for extracting information about movement patterning in studies of motor control, based on a cluster analysis of movement kinematics. In a tutorial fashion, data from three different experiments are presented to exemplify and validate the technical method. When applied to three different basketball-shooting techniques, the method clearly distinguished between the different patterns. When applied to a cyclical wrist supination-pronation task, the cluster analysis provided the same results as an analysis using the conventional discrete relative phase measure. Finally, when analyzing throwing performance constrained by distance to target, the method grouped movement patterns together according to throwing distance. In conclusion, the proposed technical method provides a valuable tool to improve understanding of coordination and control in different movement models, including multiarticular actions. © 2010 Human Kinetics, Inc.

Bril B.,Groupe de Recherche Apprentissage et Contexte | Bril B.,University of Paris Descartes | Parry R.,Paris-Sorbonne University | Parry R.,French Institute of Health and Medical Research | And 2 more authors.
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2015

Various authors have suggested similarities between tool use in early hominins and chimpanzees. This has been particularly evident in studies of nutcracking which is considered to be the most complex skill exhibited by wild apes, and has also been interpreted as a precursor of more complex stoneflaking abilities. It has been argued that there is no major qualitative difference between what the chimpanzee does when he cracks a nut and what early hominins didwhen they detached a flake from a core. In this paper, similarities and differences between skills involved in stone-flaking and nut-cracking are explored through an experimental protocol with human subjects performing both tasks. We suggest that a ‘functional’ approach to percussive action, based on the distinction between functional parameters that characterize each task and parameters that characterize the agent’s actions and movements, is a fruitful method for understanding those constraints which need to be mastered to perform each task successfully, and subsequently, the nature of skill involved in both tasks. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

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