This interdisciplinary research project will examine how language and technology, two defining human characteristics, are related to one another. The project will place emphasis on the development of human technology from early evolutionary transitions, such as stone tool-making and expansions of diets and habitats, to more recent transformations, such as agricultural, industrial, and information revolutions, in order to enhance basic understanding of these patterns of ever accelerating change, including the origins of language. The investigators will test the hypothesis that language is a special case of a more general capacity for complex, hierarchically structured, goal-oriented behavior evident in technology by integrating archaeological and neuroscience methods to investigate possible functional, anatomical, and evolutionary connections between language and tool-making. By investigating possible neural overlap between language and tool-making, the project will test major evolutionary hypotheses and promote integration between neuroscience and anthropology by developing new and broadly applicable methods for studying complex, naturalistic behavior. This project will pursue the hypothesis that hierarchical structure is a unifying principle in human cognition, crossing behavioral domains that are traditionally conceived as distinct. Project findings will have the potential to powerfully impact perceptions of the nature and origins of human intelligence.
To address questions regarding how language and technology are related to each other, this project will focus on the evolutionarily relevant, archaeologically visible behavior of stone tool-making. Louis Leakey commented that stone tools represent a form of "fossilised behavior" that can be used to make inferences about the evolution of human dexterity, cognition, and cultural transmission processes. The Early Stone Age accounts for roughly 90 percent of human prehistory, covering a time period from roughly 2.6 million years to 250,000 years before the present. The development of stone tools encompassed a technological progression from simple stone chips to skillfully shaped tools as well as a nearly three-fold increase in brain size. It is likely that many distinctive aspects of modern human brain structure and function evolved during this period. In order to study this proto-typical human technology using the modern methods of neuroscience, the investigators will teach experimental subjects to make Paleolithic tools. Cognitive, behavioral, and neurophysiological aspects of the learning process will be investigated using functional brain imaging, eye-tracking, the annotation and analysis of video-recorded tool-making action sequences, and archaeological analyses of the actual tools produced. Drawing on formal language theory, the researchers will develop new methods for describing the syntactic structure of these natural action sequences and for measuring their hierarchical complexity. Manual parsing of action sequences by expert observers will be compared with the data-driven segmentation of action streams based on the eye-movement patterns of research subjects in order to produce a robust consensus. These methods of "action syntax" analysis will be generalizable to other complex behaviors and will enable the direct comparison of hierarchical structure, information processing, and brain function across linguistic (story listening) and tool-making (action observation) behaviors in this study. This project is supported through the NSF Interdisciplinary Behavioral and Social Sciences Research (IBSS) competition.
