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

Abstract

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 of 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.

A complex adaptive system may be essential for cumulative modifications in tool design

“…Furthermore, verbal instruction gave an even greater advantage. These results support the view that the transmission of H. erectus 's stone tool-making required active teaching (Uomini, 2009;Steele & Uomini, 2009;Sinclair & Uomini, 2012;Morgan et al, 2015).…”

Articulatory capacity of Neanderthals, a very recent and human-like fossil hominin

“…At the time of writing we have archaeological and fossil anatomical evidence of population-level right-handedness in tool use in Homo heidelbergensis, Neanderthals and anatomically modern Homo sapiens [7][8][9]; these hominins are all relatively large-brained. We also have suggestive evidence of speech-relevant adaptations in the same three species from hyoid bone morphology [10,11], from analysis of the thoracic spinal canal [12], and from ancient DNA (the presence of the human form of FOXP2 in Neanderthals: [13]).…”

From action to language: comparative perspectives on primate tool use, gesture and the evolution of human language

“…But how closely coupled were these adaptive trends in the hominin lineage? Scientists have frequently considered the possibility of common underlying organizing principles in the neurophysiology of (usually spoken) language and of manual praxis, focusing, for example, on the domain-general implications of primate encephalization [2], on parallel schedules of development across domains during human ontogeny [3], on similarities in hemispheric lateralization of function [4], or on the emergence of gestural communication as an evolutionary precursor of speech [5 -8]. However, in earlier formulations, arguments for such a coupling were often complicated by clinical observations of dissociations between deficits in the linguistic and praxic domains, as well as by cases of divergent functional lateralization in healthy subjects; while to many linguists, the analogy between linguistic syntax and action organization has sometimes seemed too loosely defined to carry much interpretive weight.…”

“…Stone tools provide the longest and best-preserved archaeological record of the evolution of tool use in hominins, and there have been numerous attempts to discern indirect evidence of the emergence of language in the stone tool record ( [4,44,45]; but cf. [46]).…”