Neuroarchaeology is a “new science” that aims to find out how we became Homo sapiens.
A seated woman vigorously beats a stone against the other, making some stone chips blow away. He’s trying to get a sharp, knife-like edge. In the previous weeks, she has practiced diligently and is now able to produce a fairly efficient Olduvaian ax. Oldowan stone knives – so called because they were first found in the Gorgia of Olduvai in Tanzania – date back to a period that extends between 2.5 million and 250,000 years ago. The woman we are talking about, however, is a contemporary of ours: she is sitting in a laboratory of the University of Indiana and wearing a headset from which dozens of electrical wires connected to a machine sprout.
He is participating in a study that tests some theories on the evolution of modern human cognition. This, specifically, is an experiment that aims to understand whether the neural structures that guide the construction of the stone axes overlap at least in part with those of language (in our brain of contemporary Homo sapiens and presumably also in that of our paleolithic ancestors ). According to the hypothesis currently in vogue among scholars in the field, in fact, the cognitive processes required for the processing of stone tools were then in the course of our evolutionary history also used for language.
Unlike other similar works, Shelby Putt’s latest study found no such overlap in our brains. The research (published in Nature Human Behavior), however, fits into a new and promising sector called neuroarchaeology. Its “specific purpose”, explains Putt a il Tascabile, “is to explore the evolution of the cognitive system in order to better understand the human condition”. According to his supporters, it could help tackle problems that neuroscience and archeology have not been able to solve separately, and “help us resolve some great questions: what makes us human, how and why we have developed a cognitive system that allows us to speak, build and manipulate tools … “.
Neuroarchaeology, currently welcomed by archaeologists (especially in the field of experimental archeology), is still little considered by neuroscientists, and it is still too early, in general, to say if we are facing the birth of a new and influential trend research or if it is a new entry in the list of the many “neuro-something” that have appeared in recent decades and then remained in the background. The promises, however, are very interesting.
By combining the methods and theories of neuroscience with those of archeology, there is a good chance to understand how and why we became Homo sapiens.
According to the findings we know that Homo sapiens appeared, according to the latest research, 300,000 years ago. The behavioral aspects of our state of “wise minds” emerged quite a bit later, especially with the cultural explosion of the early Palaeolithic era. Why all this time? Establishing “when” and “where” we have become human, however fascinating and important, is not enough to understand our nature. We also need to know, and above all, “how” and “why”. By combining the methods and theories of neuroscience with those of archeology, many believe, we have a good chance of getting there.
Ancient history for a new science
Not even ten years have passed since, for the first time, the need was felt to bring archeology and neuroscience into a hybrid discipline. The occasion was the symposium, entitled “The sapient mind: archeology meets neuroscience”, held at the University of Cambridge, which brought together researchers who until then had moved more or less implicitly on the border between the two disciplines. A “founding act” from which some key figures immediately emerged, including the conference organizers, Colin Renfrew, archaeologist, paleolinguist and radiocarbon dating expert at the University of Cambridge, and Lambros Malafouris, a neuroscientist with great interest in l archeology of the University of Oxford. Renfrew and Malafouris were also the editors of a special issue of the journal Philosophical Transactions B (published by Royal Society Publishing), which gathered the most significant contributions from that meeting, laying the foundations for future developments in these researches.
“From many points of view, neuroarchaeology”, another leading figure in the sector, explains to Il Tascabile Dietrich Stout, “is simply the latest embodiment of the tradition inaugurated by cognitive archeology”. Stout, professor of anthropology at Emory University in the United States, has conducted extensive research on the construction of stone tools and is the author, together with Erin Hecht (who was a doctoral student of Stout and now works at Georgia State University), of one of the few chapters dedicated to neuroarchaeology included in a text for university courses: “Human Paleoneurology”, published by Springer.
From many points of view, neuroarchaeology is the latest incarnation of cognitive archeology, which aims to infer mental patterns starting from archaeological studies.
As Stout explains, cognitive archeology, born around the sixties and seventies, aims to infer mental skills and thought patterns starting from archaeological studies using the theories and methods of cognitive sciences. Neuroarchaeology, similarly, introduces further experimental rigor, new high-tech investigation methods and greater attention to the biological substrate (the brain) as well as to cognitive functions (the mind).
In the depths of time
The evolutionary perspective is today a fundamental element in any biological science. In brain research there is a long tradition of comparative studies which, by comparing the brain and human cognition with those of other species, have contributed enormously to reconstructing some stages of the evolution of our cognitive system. However, many shortcomings remain: “we can certainly identify the last common ancestor without a certain brain structure or cognitive function, such as chimpanzees who do not have the human brain specializations for language, the use of tools and social cognition,” explains Stout, “but this does not answer the question of how and when these specializations emerged in the next 7-8 million years”.
Neuroarchaeology could fill these gaps, thanks to the support of archaeological methods and theories: “Archeology can in fact document the chronology, geography and context in which new behaviors emerge in our species – and in the ancestors”, specifies Stout.
To clarify the steps, a concrete example is useful. Cerebral lateralization is an important feature of our brain: cognitive functions are distributed asymmetrically, with the areas of language located mainly in the left hemisphere. The predominance of the use of the right hand is a visible indication of this lateralization. We can then ask ourselves if we have always been right-handed or if this specialization emerged at some point in the course of our evolutionary history. To answer this question it is possible to observe the archaeological finds. According to a 1985 study by Nicholas Toth, the shape of prehistoric axes dating back to 1.5 million years ago shows a slight preference in the use of the right hand (about 56%), while the analysis of more recent records, the cave paintings dating back to about 30,000 years found in France and Spain show that around 75% of the individuals who designed them used their right hand. These and other observations support the idea that the preference for the right hand has evolved throughout human history, suggesting the possibility of progressive cerebral lateralization, with consequences perhaps on the development of language.
The tools of archeology, intertwined with those of neuroscience, allow us to formulate hypotheses on the behaviors related to objects and tell a story that otherwise it would not have been possible to reconstruct.
The tools of archeology, which thanks to experimental replication and ethnographic analogy allow researchers to formulate hypotheses on the behaviors that objects imply (the use of the right or left hand), are intertwined with those of neuroscience (knowledge on lateralization cerebral) and allow us to tell a story that with other methods it would not be possible to reconstruct.
The object is everything
Archeology has developed precise and codified methods for deducing human behavior from the study of objects. This “focus” on the object could be the card that neuroarchaeology can play to gain a prominent position within neuroscience. To understand this passage, a brief review of the recent history of scientific studies on mind and brain is perhaps useful.
In the second half of the last century, the cognitivist approach dominated: the mind is a system of elaboration of abstract symbols. The information collected by the sensory systems, which maintain a form of analogy with the material world, is encoded and processed in a symbolic, abstract form, completely unrelated to the material nature of the input. Thought and the external world are therefore completely different things.
In reaction to this approach, in the last decades, starting from the nineties, a new paradigm has taken hold, usually identified with the term embodied cognition, embedded cognition (but we also speak of grounded cognition, extended mind, etc.) which gives great emphasis to the “material” aspect of human cognition. According to this approach, the mind also at the coding and processing level maintains an analogy with sensory stimulation (or motor output). According to built-in theories, for example, when we have to understand the word that indicates a color in our brain, the perceptual areas that process the color are also activated.
The most recent neurosciences see in the material world a fundamental element of cognitive functions, to the point that man-made objects would be at the same time products and extensions of the cognitive system.
Therefore, the importance of objects in more recent neurosciences appears clear, seeing the material world as a fundamental element of cognitive functions. According to the most “pushed” versions of these approaches, man-made objects are at the same time products and extensions of the cognitive system. “Like the Mycenaean tablets,” explains Stout, used as accounting documents, “which according to some scholars become extensions of the memory of a cognitive system that includes reading and writing among its functions”.
Some “race” neuroscientists have already made “neuroarchaeological” incursions, such as Ramachandran Vilayanur, who in 2000 suggested that the cultural explosion of the Upper Palaeolithic era could be explained by mirror neurons (which would have favored learning by observation).
“The future of neuroarchaeology as a simple niche within archeology or as a science in its own right will ultimately depend on its relevance to the problems and scientific agendas of neuroscientists,” explains Stout. He adds jokingly: “If you ask me, of course, I will tell you that there will never be enough attention. But, seriously, I must say that I am very pleased to see how curiosity is increasing and, above all, that there is an increasing interest on the part of the scientific community to collaborate with us neuroarchaeologists “.