Cognitive archaeology, and the psychological assessment of extinct minds

Evolutionary anthropology relies on both neontological and paleontological information. In the latter case, fields such as paleoneurology, neuroarchaeology, and cognitive archaeology are supplying new perspectives in prehistory and neuroscience. Cognitive archaeology, in particular, investigates the behaviors associated with extinct species or cultures according to specific psychological models. For example, changes in working memory, attention, or visuospatial integration can be postulated when related behavioral changes are described in the archaeological record. However, cognition is a process based on different and partially independent functional elements, and extinct species could hence have evolved distinct combinations of cognitive abilities or features, based on both quantitative and qualitative differences. Accordingly, differences in working memory can lead to more conceptual or more holistic mindsets, with important changes in the perception and management of the mental experience. The parietal cortex is particularly interesting, in this sense, being involved in functions associated with body-tool integration, attention, and visual imaging. In some cases, evolutionary mismatches among these elements can induce drawbacks that, despite their positive effects on natural selection, can introduce important constraints in our own mental skills. Beyond the theoretical background, some hypotheses can be tested following methods in experimental psychology. In any case, theories in cognitive evolution must acknowledge that, beyond the brain and its biology, the human mind is also deeply rooted in body perception, in social networks, and in technological extension.

The parietal lobe evolution and the emergence of material culture in the human genus

Traditional and new disciplines converge in suggesting that the parietal lobe underwent a considerable expansion during human evolution. Through the study of endocasts and shape analysis, paleoneurology has shown an increased globularity of the braincase and bulging of the parietal region in modern humans, as compared to other human species, including Neandertals. Cortical complexity increased in both the superior and inferior parietal lobules. Emerging fields bridging archaeology and neuroscience supply further evidence of the involvement of the parietal cortex in human-specific behaviors related to visuospatial capacity, technological integration, self-awareness, numerosity, mathematical reasoning and language. Here, we complement these inferences on the parietal lobe evolution, with results from more classical neuroscience disciplines, such as behavioral neurophysiology, functional neuroimaging, and brain lesions; and apply these to define the neural substrates and the role of the parietal lobes in the emergence of functions at the core of material culture, such as tool-making, tool use and constructional abilities.

Visuospatial Integration and Hand-Tool Interaction in Cognitive Archaeology

Testing cognitive hypotheses in extinct species can be challenging, but it can be done through the integration of independent sources of information (e.g., anatomy, archaeology, neurobiology, psychology), and validated with quantitative and experimental approaches. The parietal cortex has undergone changes and specializations in humans, probably in regions involved in visuospatial integration. Visual imagery and hand-eye coordination are crucial for a species with a remarkable technological and symbolic capacity. Hand-tool relationships are not only a matter of spatial planning but involve deeper cognitive levels that concern body cognition, self-awareness, and the ability to integrate tools into body schemes, extending the body's functional and structural range. Therefore, a co-evolution between body and technology is to be expected not only in terms of anatomical correspondence but also in terms of cognitive integration. In prehistory, lithic tools are crucial in the interpretation of the cognitive abilities of extinct human species. The shape of tools and the grasping patterns associated with the corresponding haptic experience can supply some basic quantitative approaches to evaluate changes in the archaeological record. At the physiological level, electrodermal activity can be used as proxy to investigate the cognitive response during haptic experiences, revealing differences between tools and between subjects. These approaches can be also useful to evaluate whether and to what extent our complex cognitive resources are based on the capacity to export and delegate functions to external technological components.

Experimental heat treatment of silcrete implies analogical reasoning in the Middle Stone Age

Siliceous rocks that were not heated to high temperatures during their geological formation display improved knapping qualities when they are subjected to controlled heating. Experimental heat treatment of South African silcrete, using open fires of the kind used during the Middle Stone Age, shows that the process needed careful management, notwithstanding recent arguments to the contrary. Silcrete blocks fractured when heated on the surface of open fires or on coal beds, but were heated without mishap when buried in sand below a fire. Three silcrete samples, a control, a block heated underground with maximum temperature between 400 and 500 °C and a block heated in an open fire with maximum temperature between 700 and 800 °C, were analysed with X-ray powder diffraction (XRD), X-ray fluorescence (XRF), optical microscopy, and both Fourier transform infrared (FTIR) and Raman spectroscopy. The results show that the volume expansion during the thermally induced α- to β-quartz phase transformation and the volume contraction during cooling play a major role in the heat treatment of silcrete. Rapid heating or cooling through the phase transformation at 573 °C will cause fracture of the silcrete. Successful heat treatment requires controlling surface fire temperatures in order to obtain the appropriate underground temperatures to stay below the quartz inversion temperature. Heat treatment of rocks is a transformative technology that requires skilled use of fire. This process involves analogical reasoning, which is an attribute of complex cognition.

The modularity debate in evolutionary psychology

The adherence of evolutionary psychology (EP) to the massive modularity thesis has generated considerable controversy. Barrett and Kurzban argue that much of the debate is misplaced because critics have incorrectly characterized the sense of modularity involved in EP. They offer an account centered on “functional specialization,” an emphasis on formal properties of representations, and an eschewing of references to content domains. We argue that their concept of modularity is at odds with the claims made by EP advocates. Indeed, their definition of modularity is so broad that it includes mechanisms traditionally rejected by EP. Furthermore, their concept of modularity has limited usefulness in explaining the existence of mechanisms designed to deal with novel challenges and with the development of novel solutions to longstanding adaptive problems. A model based on Potts’ concept of “variability selection” is offered as an explanation of such mechanisms.

Evolution, Psychology, and a Conflict Theory of Culture

This article develops an evolutionary theory of conflict over the construction of culture that is informed by current knowledge of psychological mechanisms. Psychological mechanisms important for the production of culture include (1) general intelligence (including the ability to engender hypothetical scenarios and means-end reasoning necessary for constructing tools and other exemplars of technology); (2) explicit processing mechanisms (e.g., symbolic representations of the world). Explicit processing allows humans to regulate modular mechanisms in accordance with culturally constructed norms and culturally constructed cost/benefit payoff schedules. It also enables active attempts to construct culture in accordance with explicit perceptions of possible costs and benefits. Because people have different construals of the costs and benefits of particular forms of culture, there is conflict over the construction of culture. Social controls and ideologies are introduced as general cultural categories that are enabled by explicit processing and which are able to regulate and motivate behavior within particular historical contexts, at times in ways that conflict with evolved predispositions. Ideologies are often intimately intertwined with various social controls but are logically and psychologically independent from social controls. Ideologies typically rationalize extant social controls but they also benefit from the power of social controls to enforce ideological conformity in schools or in religious institutions. Because of the control of explicit processing over behavior, this theory predicts that conflicts over culture will often be intense. Discussion deals with the implications of this model for group selection, cultural transmission, gene-culture co-evolution, and the various types of conflicts of interest apparent in conflicts over the construction of culture.

"Neuroarchaeology": exploring the links between neural and cultural plasticity

This paper aims primarily at two things: The first is to present an overview of the newly developed field of "neuroarchaeology" and discuss its theoretical grounding in Material Engagement Theory (MET) and the extended mind hypothesis. The second is to use the above overview as a basis for advancing some tentative proposals about the role that neuroarchaeology, by placing the mutual constitution of brain, mind, and culture in evolutionary perspective, can play within the field of cultural neuroscience and about the common benefits that can arise out of such a cross-disciplinary coalition.

The expert Neandertal mind

Cognitive neuropsychology, cognitive anthropology, and cognitive archaeology are combined to yield a picture of Neandertal cognition in which expert performance via long-term working memory is the centerpiece of problem solving. This component of Neandertal cognition appears to have been modern in scope. However, Neandertals' working memory capacity, which is the ability to hold a variety of information in active attention, may not have been as large as that of modern humans. This characteristic helps us understand features of the archaeological record, such as the rarity of innovation, and allows us to make empirically based speculations about Neandertal personality.