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Dive into the research topics where Bruce A. Bradley is active.

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Featured researches published by Bruce A. Bradley.


World Archaeology | 2004

The North Atlantic ice-edge corridor: a possible Palaeolithic route to the New World

Bruce A. Bradley; Dennis J. Stanford

The early peopling of the New World has been a topic of intense research since the early twentieth century. We contend that the exclusive focus of research on a Beringian entry point has not been productive. Evidence has accumulated over the past two decades indicating that the earliest origin of people in North America may have been from south-western Europe during the last glacial maximum. In this summary we outline a theory of a Solutrean origin for Clovis culture and briefly present the archaeological data supporting this assertion.


PLOS ONE | 2010

The Manipulative Complexity of Lower Paleolithic Stone Toolmaking

A. Aldo Faisal; Dietrich Stout; Jan Apel; Bruce A. Bradley

Background Early stone tools provide direct evidence of human cognitive and behavioral evolution that is otherwise unavailable. Proper interpretation of these data requires a robust interpretive framework linking archaeological evidence to specific behavioral and cognitive actions. Methodology/Principal Findings Here we employ a data glove to record manual joint angles in a modern experimental toolmaker (the 4th author) replicating ancient tool forms in order to characterize and compare the manipulative complexity of two major Lower Paleolithic technologies (Oldowan and Acheulean). To this end we used a principled and general measure of behavioral complexity based on the statistics of joint movements. Conclusions/Significance This allowed us to confirm that previously observed differences in brain activation associated with Oldowan versus Acheulean technologies reflect higher-level behavior organization rather than lower-level differences in manipulative complexity. This conclusion is consistent with a scenario in which the earliest stages of human technological evolution depended on novel perceptual-motor capacities (such as the control of joint stiffness) whereas later developments increasingly relied on enhanced mechanisms for cognitive control. This further suggests possible links between toolmaking and language evolution.


Archive | 1993

Paleo-Indian Flaked Stone Technology in the North American High Plains

Bruce A. Bradley

In the past two decades, a major change has occurred in the way Paleo-Indian researchers view flaked stone artifacts. No longer are “finished tools” simply classified and compared. Gone are the days of simple functional typologies. It is now generally accepted that flaked stone artifacts became part of the archaeological record as the result of manufacture, use, reuse, discard, and natural site formation processes. Flaked stone assemblages from the High Plains have been increasingly analyzed within the concept of these dynamic systems. Indeed, it is the systems themselves that are being used to characterize cultural norms.


American Antiquity | 2011

MIDDLE PALEOLITHIC SKILL LEVEL AND THE INDIVIDUAL KNAPPER: AN EXPERIMENT

Metin I. Eren; Bruce A. Bradley; C. Garth Sampson

It has been proposed that Paleolithic studies should abandon their focus on groups and turn instead to the individual. If individuals are to emerge from the lithics-dominated Middle Paleolithic record, the best chance of success is to identify the products of learner knappers from those of their mentors. To do so we need a framework of knapping standards by which to measure Middle Paleolithic skill level. Selected measurements on a sequence of 100 subcircular Levallois tortoise core reductions by a knapper of intermediate skill were compared with 25 reductions by his highly experienced instructor. Four measures emerge as potential markers of skill level: total stone consumption during initial core preparation, consumption from the upper and lower core surface, symmetry of the first detached Levallois flake, and failure rate of that detachment by overshooting the cores rim. These markers allow us to discriminate between the work of a modern learner and his mentor, but > 30 percent were misclassified. The learning trajectory is more complex than the mere honing of skills through practice and is punctuated by increasing numbers of mentor-like reductions. It follows that skill-level measures on their own are imperfect discriminators. Personal markers other than those of skill level must be found by which to seek individuals in the Middle Paleolithic record.


Plains Anthropologist | 1976

QUANTITATIVE VARIATIONS IN FLAKED STONE DEBITAGE

Henry O. Don; C. Vance Haynes; Bruce A. Bradley

In an attempt to discern the quantitative para meters diagnostic of specific load applications (i.e. hard- and soft-hammer percussion and pressure flaking) used in flint knapping, approximately 1,500 experimentally produced flakes were analyzed. Load varieties were recorded during production, flakes were standardized as to plane size through graduated sieves, and weighed and measured for maximum thicknesses. Although the study indicates that hard and soft-hammer percussion do not yield significantly different debitage weights or thicknesses, pressure flakes can be differentiated from percussion spalls on the basis of these variables. Prehistorians have become increasingly concerned with deriving information from as many aspects of the archaeological record as possible. One area of emphasis is in the study of the various processes related to the manufacture of lithic tools. This interest in stone tool technology has expanded lithic analyses so as to include all pieces of lithic material associated with stone tool pro duction, not only tool forms.


NeuroImage | 2015

Virtual dissection and comparative connectivity of the superior longitudinal fasciculus in chimpanzees and humans.

Erin Hecht; David A. Gutman; Bruce A. Bradley; Todd M. Preuss; Dietrich Stout

Many of the behavioral capacities that distinguish humans from other primates rely on fronto-parietal circuits. The superior longitudinal fasciculus (SLF) is the primary white matter tract connecting lateral frontal with lateral parietal regions; it is distinct from the arcuate fasciculus, which interconnects the frontal and temporal lobes. Here we report a direct, quantitative comparison of SLF connectivity using virtual in vivo dissection of the SLF in chimpanzees and humans. SLF I, the superior-most branch of the SLF, showed similar patterns of connectivity between humans and chimpanzees, and was proportionally volumetrically larger in chimpanzees. SLF II, the middle branch, and SLF III, the inferior-most branch, showed species differences in frontal connectivity. In humans, SLF II showed greater connectivity with dorsolateral prefrontal cortex, whereas in chimps SLF II showed greater connectivity with the inferior frontal gyrus. SLF III was right-lateralized and proportionally volumetrically larger in humans, and human SLF III showed relatively reduced connectivity with dorsal premotor cortex and greater extension into the anterior inferior frontal gyrus, especially in the right hemisphere. These results have implications for the evolution of fronto-parietal functions including spatial attention to observed actions, social learning, and tool use, and are in line with previous research suggesting a unique role for the right anterior inferior frontal gyrus in the evolution of human fronto-parietal network architecture.


The Horner Site#R##N#The Type Site of the Cody Cultural Complex | 1987

Projectile Points and Specialized Bifaces from the Horner Site

Bruce A. Bradley; George C. Frison

Publisher Summary This chapter describes the projectile points and specialized bifaces found at the Horner site. The 1977 and 1978, excavations by the University of Wyoming at the Horner site made it apparent that with the additional data, a more in-depth study should be undertaken, especially as many of the projectile points from the site did not seem to fit into the typological categories that have been described as occurring in the Cody Complex. All the materials recovered from the site since the start of work by a Princeton expedition in 1949 have been assembled. This has enabled a thorough reexamination and reevaluation to be made. The circumstances surrounding the context of many of the projectile points that were recovered from the Horner site before and during the Princeton excavations in 1949 have been extremely difficult to reconstruct. Quite a number of the specimens seem to have been collected from the surface in the general site vicinity and simply added to the collection. Because of this, it was deemed prudent to study only those pieces that undisputedly were recovered in a context indicating association with the site strata.


World Archaeology | 2008

Solutrean laurel leaf production at Maîtreaux: an experimental approach guided by techno-economic analysis

Thierry Aubry; Bruce A. Bradley; Miguel Almeida; Bertrand Walter; Maria Joao Neves; Jacques Pelegrin; Michel Lenoir; Marc Tiffagom

Abstract Large-sized Solutrean laurel leaf typology has been defined on the basis of the exceptional pieces found at Volgu, France, in 1874. The geographical distribution of this rare type of large bifacial piece is limited to the border of the French Massif Central. Located at the northern limit of this distribution area, the Maîtreaux site provides new data on the reduction schemes of these pieces. Refitted sequences indicate that the Solutrean presence was motivated by the exploitation of local flint resources to produce reserves of lithic tools and/or blanks, elements for composite projectiles and preforms for exportation and later finishing and use/retouch elsewhere. Results of techno-economic and spatial analyses are compared with those of an experimental project, mostly centred on laurel leaf techno-economy. This integrated experimental approach strongly contributes to the on-going social interpretation of the Maîtreaux group, allowing us better to characterize and quantify the remains of laurel leaf reduction processes. Also produced were in situ‘undisturbed’ knapping features for taphonomic reference and interpretation.  At the site scale, experimental work coupled with spatial and techno-economic analysis is relevant for the interpretation of different geoarchaeological, technical and social aspects of the archaeological record. At a regional scale, experimental work on the available raw materials in each geographic zone is required to clarify issues related to raw-material procurement, exploitation and circulation, such as regional lithic resource exploitation strategies and inter-site discontinuities of production.


Lithic technology | 2009

Experimental Evaluation of the Levallois “Core Shape Maintenance” Hypothesis

Metin I. Eren; Bruce A. Bradley

... that the removal of the larger central flakes ... was predominately a core maintenance technique intended to mitigate the problem of the increasing convexity and central mass of the surface of Levallois (and other types of single-surface cores). Unless this tendency is addressed, it will prevent the maintenance of consistent core morphology throughout the course of reduction. (Sandgathe 2004:147).


Lithic technology | 2014

CONTROLLED OVERSHOT FLAKING: A RESPONSE TO EREN, PATTEN, O'BRIEN, AND MELTZER

Jon C. Lohse; Michael B. Collins; Bruce A. Bradley

A recent article by Eren et al. () is the latest criticism of the hypothesis that some Late Pleistocene Solutrean groups from western Iberia came to the New World and that lasting vestiges of this contact can be seen in close similarities between Solutrean and Clovis biface and blade technologies. Eren et al.’s primary argument is that overshot flaking, one of many technological characteristics shared in common by Clovis and some Solutrean cultures, was an accident that both cultural systems happened to have made and should be interpreted as cultural convergence rather than evidence for cultural connections or influences. We find their article and the experiment used to support it deeply problematic for several reasons. Indeed, the flawed logic employed in their study and the distortions of earlier versions of the Ice Edge Hypothesis are so egregious that we question how the manuscript passed through the peer-review process into publication in a venue as highly regarded as the Journal of Archaeological Science. Here, we address some of Eren et al.’s most obvious errors, misrepresentations, and over statements. In addition to correcting the record, we are motivated by a desire to see scientific discourse, particularly on an issue as important as understanding the New World’s earliest occupants, conducted in a scholarly, professional manner that involves fair and honest evaluation of appropriate data. The Ice-Edge Hypothesis (IEH) states that some unknown number of Solutrean peoples came in watercraft across the Northern Atlantic from western Iberia to the New World during the Last Glacial Maximum. Furthermore, the contributions of these peoples to early stone tool technologies can be seen in Clovis and possibly pre-Clovis biface and blade manufacture, along with other traits. While the idea that people from Upper Paleolithic Europe came to the New World is not new (see Straus ), details of the IEH have recently been elaborated by Bruce Bradley and Dennis Stanford (Bradley and Stanford , ; Stanford and Bradley ), who note significant similarities between Clovis and Solutrean flaked stone and other technologies. The argument has been critiqued (Balter ; Straus ; Straus et al. ), sometimes using a derisive style of commentary (Meltzer : –). The recent article by Eren, Patten, O’Brien, and Meltzer, “Refuting the technological cornerstone of the Ice-Age Atlantic crossing hypothesis,” (Eren et al. ) is the latest effort to debunk this idea while again employing an unprofessional tone. The IEH has been proposed as, and is best considered to be, a working hypothesis (see Stanford and Bradley : ) explaining some of the New World’s cultural origins. We see the settlement of the Americas as a complex issue requiring advances in many lines of study, throughout the Americas, for years if not generations to come. When it comes to conducting academic discourse on topics of high importance we agree with Straus (: ) with respect to the importance of “standards of argument proof.” We feel strongly that the recent article by Eren et al. is so deeply flawed that it contributes very little to the topic it purports to address, or even to studies of Clovis, Early Paleoamericans, Pleistocene North America, or nearly any other issue. In this rebuttal, we address what we feel are some of the more outstanding problems. According to Eren et al.’s summary of the IEH, controlled overshot (also known as outre passe) flaking, the removal of flakes spanning the width of a biface and removing a small amount of mass from each margin, is presented as the single most important trait shared by Clovis and Solutrean (Eren et al. : ). They claim that the key testable component of the IEH is whether

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Metin I. Eren

Southern Methodist University

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Erin Hecht

Georgia State University

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Chris Clarkson

University of Queensland

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