Cognitive archaeology may be divided into two branches. Evolutionary cognitive archaeology (ECA) is the discipline of prehistoric archaeology that studies the evolution of human cognition. Practitioners are united by a methodological commitment to the idea that archaeological traces of past activity provide access to the minds of the agents responsible. The second branch, ideational cognitive archaeology, encompasses archaeologists who strive to discover the meaning of symbolic system, primarily through the analysis of iconography. This approach differs from ECA in its epistemology, historical roots, and citation universes, and focuses on comparatively recent time periods (after 10,000 years ago). Evolutionary cognitive archaeologists are concerned with the nature of cognition itself, and its evolutionary development from the time of the last common ancestor with chimpanzees to the final ascendancy of modern humans at the end of the Pleistocene. Although ECA methods are primarily archaeological, its theoretical grounding is in the cognitive sciences, including cognitive psychology, neuropsychology, and cognitive neuroscience. It is by its nature interdisciplinary. ECA differs from the allied discipline of evolutionary psychology in several important respects. Methodologically, ECA is a macroevolutionary science that studies physical evidence of past human cognition, including archaeological and fossil remains. Evolutionary psychology relies heavily on reverse engineering from controlled experiments on living humans. Theoretically, ECA is more eclectic, drawing on a variety of cognitive and evolutionary models; evolutionary psychology is committed to a neo-Darwinian, selectionist understanding of evolutionary change. The two approaches tend to study different components of human mental life, but are not inherently contradictory. ECA practitioners reconstruct prehistoric activities using well-established archaeological methods and techniques, including morphological analysis of artifacts to identify action sequences and decision patterns, functional analyses (e.g., microwear) to identify use patterns, and spatial patterns within sites to recognize activity loci (e.g., hearths). An increasingly important method is the actualistic recreation of prehistoric technologies to identify features not preserved in the archaeological remains. Neuroarchaeologists enhance such actualistic research by imaging the brains of the participants (most typically using fMRI), an approach that also contributes directly to cognitive science’s understanding of the neural basis of technical cognition. ECA practitioners take two non-mutually exclusive approaches to documenting human cognitive evolution. The first approach enriches the understanding of specific hominin taxa (i.e., Homo sapiens and their direct ancestors since 6 million years ago) by providing accounts of their cognitive life worlds, or by contrasting two taxa with one another. This approach is famously exemplified by attempts to contrast the abilities of Neandertals with those of modern humans. The second approach traces the evolution of specific cognitive abilities from the first appearance of stone tools 3.3 million years ago to the emergence of city-states 5,000 years ago. The range of accessible cognitive abilities is limited by the nature of archaeological remains, but evolutionary cognitive archaeologists have been able to trace developments in spatial cognition, memory, cognitive control, technical expertise, theory of mind, aesthetic cognition, symbolism, language, and numeracy.
Recent origin of low trabecular bone density in modern humans