The value of praxis-based studies for understanding language evolution

Lana RUCK, Indiana University, Bloomington

Alternative functions of the left-hemisphere dominant BrocaÕs region have induced hypotheses regarding the evolutionary parallels between manual praxis and language in humans. Many recent studies on Bro-caÕs area reveal several assumptions about the cognitive mechanisms that underlie both functions, including: (1) an accurate, finely controlled body schema, (2) increasing syntactical abilities, particularly for goal-oriented actions, and (3) bilaterality and fronto-parietal connectivity. Although these characteristics are supported by experimental paradigms, many researchers have failed to acknowledge a major line of evidence for the evolutionary development of these traits: stone tools. The neuroscience of stone tool manufacture is a viable proxy for understanding evolutionary aspects of manual praxis and language, and may provide key information for evaluating competing hypotheses on the co-evolution of these cognitive domains in our species.