Dietrich Stout - US grants

In the distant past, our ancestors experienced highly variable environmental and climatic conditions. During the Middle Stone Age, a period extending from 250,000 to 30,000 years ago, early humans experienced a series of wet/dry cycles in Africa related to ice age climates in more temperate parts of the world. Although theories of modern human origins and the evolution of human-like culture and behavior are generally based in the Middle Stone Age of Africa, our understanding of what makes the Middle Stone Age so important for these modern human features is limited.

One avenue of research is to investigate the nature of these cycles of glaciation in equatorial and southern African habitats where the earliest evidence for evolution of our species exists. In this project, conducted by Emory University doctoral student Joshua Robinson, under the mentorship of Dr. John Kingston, a series of established Middle Stone Age sites in Kenya, Ethiopia, Zambia, and the Democratic Republic of Congo will be utilized to study the local manifestations of global and regional environmental and climatic events. Through chemical analyses of the teeth of fossil animals from these archaeological sites, the research will reconstruct dietary patterns and climatic conditions. Specifically, carbon and oxygen isotopic analyses will form the basis for reconstructing vegetation, humidity, and rainfall at eight sample sites. These analyses will directly test the hypothesis that regional records fail to document local conditions that might be associated with these evolutionary innovations.

The ultimate goal of the research is to improve our understanding of the development of distinctly modern human behaviors, and the relationship between behavior and climate. This relationship is one of the enduring questions in anthropology, and the data to be collected here will provide new insights into when modern behavior emerged and delineate possible reasons for this emergence. The high-resolution, long-term database of environmental and climatic data generated by the study also will find broader application as an innovative framework for contextualizing and understanding modern climate change.

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.

The human ability to create and use technology far surpasses that of any other species. How did our advanced technological skills evolve, and what can this evolutionary perspective tell us about the basis of modern human technological learning? A team of investigators from Georgia State University and Emory University will use a multidisciplinary approach, integrating expertise in neuroscience, informatics, anthropology, biomedical engineering, and educational psychology, to address three main questions: (1) What aspects of human brain connectivity show greatest variability across individuals? (2) Are these highly variable regions responsive to real-world technological skill training, and, if so, what are the factors mediating individual differences in response to this training? (3) Which aspects of the underlying brain networks are present in humans but not our closest living relatives, chimpanzees, and therefore implicated as a likely substrate for unique human abilities for technological learning? The findings will have the potential to reveal the functional significance of any unique features of human brain organization that may be related to the learning and transfer of complex technological skills, thereby expanding knowledge of ourselves and of the brain with implications for STEM education. The award is from the Integrated Strategies for Understanding Neural and Cognitive Systems program, with funding from the EHR Core Research (ECR) program, which supports fundamental research that advances the research literature on STEM learning, and the SBE Office of Multidisciplinary Activities (SMA) program.

The investigators hypothesize that the ability to learn complex technological skills evolved by means of adaptations to prefrontal-parietal-temporal association networks, and that the high individual variability of these regions is due to selection for increased plasticity and protracted development, allowing for a greater input of individual experience, social learning, and cultural context. The researchers will examine human brain morphology and connectivity before, during, and after two STEM learning experiences (tool making and computer programming) and relate the pre-post changes in the brain to differences in connectivity in humans and chimpanzees. The human brain map produced will also provide a normative foundation to support and stimulate research on other questions, such as neural predictors of individual variation in behavior or in disease states). Finally, the team will develop an open source analysis tool, voxel-based connectivity, that will help the field by closing a gap in current neuroimaging methodology.

Humans have remarkably plastic brains; adaptations for learning are perhaps the hallmark evolutionary trait of our species. This project will examine learning-related aspects of brain organization in great ape species that are close evolutionary relatives of humans – bonobos and chimpanzees – using noninvasive tests and archived brain samples and images. The work focuses on two learned skills that were important factors in human evolution: tool use and language. One analysis will use archived brain images from previous studies combined with new behavioral tests of skill learning. Apes will receive training in evolutionarily-relevant, naturalistic tool use skills, and the investigators will measure how individual variation in brain organization is related to skill learning. Another analysis will examine brain organization in apes that have and have not undergone training to use language-like systems, including hand signs and pictogram boards. The investigators will examine how language training is related to learning-related changes in the brain. Results are expected to shed light on probable brain changes during the evolution of the human species, provide insight on neural mechanisms of real-world skill learning in primate species closely related to humans, and facilitate understanding of how individual variation in brain structure is related to individual variation in behavior and cognition.<br/> <br/>This project will use a cross-disciplinary, comparative, integrative approach to examine how individual variation in brain anatomy influences learning trajectories in the context of real-world, evolutionarily relevant skills. It also examines the interaction between acquired, plastic changes in the brain resulting from learning during an individual’s lifetime, and evolved, heritable changes resulting from natural selection across generations. The project brings together methodological and theoretical approaches from neuroscience and neuroimaging, anthropology, archaeology, and animal behavior. Identification of plastic changes resulting from language training in great apes will provide a new window on the evolution of language circuits in our own species and will for the first time add crucial neurobiological information to landmark, long-running language-training studies in apes. Additionally, individual variation in chimpanzee and bonobo brain anatomy will be linked to differences in learning trajectories in two evolutionarily-relevant, real-world skills: simple stone tool knapping and nut cracking. Together, this research will provide important new insight on brain changes underlying acquisition of learned skills both on the timescale of individual lifetimes (plasticity) and the timescale of evolved, species-level change (adaptation).<br/><br/>This project is funded by the Integrated Strategies for Understanding Neural and Cognitive Systems (NCS) program, which is jointly supported by the Directorates for Computer and Information Science and Engineering (CISE), Education and Human Resources (EHR), Engineering (ENG), and Social, Behavioral, and Economic Sciences (SBE).<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.