We live in an era of mass migration. According to the United Nations’ World Migration Report 2022, there were 281 million international migrants in 2020, equaling 3.6 percent of the global population. That’s well over twice the number in 1990 and over three times the estimated number in 1970. In countries that receive them, migrants are often blamed, rightly or wrongly, for everything from higher crime to declining wages to social and cultural disruption.
But the frictions provoked by migration are not new problems; they are deeply embedded in human history and even prehistory. Taking a long-term, cultural-historical perspective on human population movements can help us reach a better understanding of the forces that have governed them over time, and that continue to do so. By anchoring our understanding in data from the archeological record, we can uncover the hidden trends in human migration patterns and discern (or at least form more robust hypotheses about) our species’ present condition—and, perhaps, formulate useful future scenarios.
Globalization in the modern context, including large-scale migrations and the modern notion of the “state,” traces back to Eurasia in the period when humans first organized themselves into spatially delimited clusters united by imaginary cultural boundaries. The archeological record shows that after the last glacial period—ending about 11,700 years ago—intensified trade sharpened the concept of borders even further. This facilitated the control and manipulation of ever-larger social units by intensifying the power of symbolic constructions of identity and the self.
Then as now, cultural consensus created and reinforced notions of territorial unity by excluding “others” who lived in different areas and displayed different behavioral patterns. Each nation elaborated its own story with its own perceived succession of historical events. These stories were often modified to favor some members of the social unit and justify exclusionist policies toward peoples classified as others. Often, as they grew more elaborate, these stories left prehistory by the wayside, conveniently negating the common origins of the human family. The triggers that may first have prompted human populations to migrate into new territories were probably biological and subject to changing climatic conditions. Later, and especially after the emergence of our own species, Homo sapiens, the impulse to migrate assumed new facets linked to culture.
From Nomadism to Migration
The oldest migrations by hominins—the group consisting of humans, extinct human species, and all our immediate ancestors—took place after the emergence of our genus, Homo, in Africa some 2.8 million years ago and coincided roughly with the appearance of the first recognizably “human” technologies: systematically modified stones. Interestingly, these early “Oldowan” tool kits (after the Olduvai Gorge site in Tanzania) were probably made not only by our genus but also by other hominins, including Paranthropus and Australopithecines.
What role did stone tools play in these early steps along our evolutionary path? Archeology tells us that ancient humans increasingly invested in toolmaking as an adaptive strategy that provided them with some advantages for survival. We see this in the noticeable increase in the geographical distribution of archeological sites beginning about 2 million years ago. This coincided with rising populations and also with the first significant hominin migrations out of Africa and into Eurasia.
Toolmaking in Oldowan technocomplexes—distinct cultures that use specific technologies—shows the systematic repetition of very specific chains of operations applied to stone. This suggests that the techniques must have been learned and then incorporated into the sociobehavioral norms of the hominin groups that practiced them. In fact, there are similarities between the first Eurasian stone tool kits and those produced at the same time in Africa. Technological know-how was being learned and transmitted—and that implies that hominins were entering into a whole new realm of culture.
While the archeological record dating to this period is still fragmentary, there is evidence of a hominin presence in widely separated parts of Eurasia—China and Georgia—from as early as 2 million to 1.8 million years ago; we know that hominins were also present in the Near East and Western Europe by around 1.6 million to 1.4 million years ago. While there is no evidence suggesting that they had mastered fire making, their ability to thrive in a variety of landscapes—even in regions quite different from their original African savannah home—demonstrates their impressive adaptive flexibility. I believe that we can attribute this capacity largely to toolmaking and socialization.
How can we envision these first phases of human migrations?
We know that there were different species of Homo (Homo georgicus, Homo antecessor) and that these pioneering groups were free-ranging. Population density was low, implying that different groups rarely encountered each other in the same landscape. While they certainly competed for resources with other large carnivores, this was probably manageable thanks to a profusion of natural resources and the hominins’ technological competence.
From around 1.75 million years ago in Africa and 1 million years ago in Eurasia, these hominins and their related descendants created new types of stone tool kits, referred to as “Acheulian” (after the Saint-Acheul site in France). These are remarkable for their intricacy, the standardization of their design, and the dexterity with which they were fashioned. While the Acheulian tool kits contained a fixed assortment of tool types, some tools for the first time displayed regionally specific designs that prehistorians have identified with specific cultural groups. As early as 1 million years ago, they had also learned to make fire.
Acheulian-producing peoples—principally of the Homo erectus group—were a fast-growing population, and evidence of their presence appears in a wide variety of locations that sometimes yield high densities of archeological finds. While nomadic, Acheulian hominins came to occupy a wide geographical landscape. By the final Acheulian phase, beginning around 500,000 years ago, higher population density would have increased the likelihood of encounters between groups that we know were ranging within more strictly defined geographical radiuses. Home base-type habitats emerged, indicating that these hominin groups returned cyclically to the same areas, which can be identified by characteristic differences in their tool kits.
After the Oldowan, the Acheulean was the longest cultural phase in human history, lasting some 1.4 million years; toward its end, our genus had reached a sufficiently complex stage of cultural and behavioral development to promulgate a profoundly new kind of cognitive awareness: the awareness of self, accompanied by a sense of belonging within a definable cultural unit. This consciousness of culturally based differences eventually favored the separation of groups living in diverse areas based on geographically defined behavioral and technological norms. This was a hugely significant event in human evolution, implying the first inklings of “identity” as a concept founded on symbolically manufactured differences: that is, on ways of doing or making things.
At the same time, the evidence suggests that networking between these increasingly distinct populations intensified, favoring all sorts of interchange: exchange of mates to improve gene pool variability, for example, and sharing of technological know-how to accelerate and improve adaptive processes. We can only speculate about other kinds of relations that might have developed—trading of stories, beliefs, customs, or even culinary or medicinal customs—since “advanced” symbolic communicative networking, emblematic of both Neandertals and humans, has so far only been recognized from the Middle Paleolithic period, from 350,000 to 30,000 years ago.
Importantly, no evidence from the vast chronological periods we have outlined so far suggests that these multilayered encounters involved significant inter- or intraspecies violence.
That remained the case moving into the Middle Paleolithic, as the human family expanded to include other species of Homo over a wide territorial range: Neandertals, Denisovans, Homo floresiensis, Homo luzonensis, Homo naledi, Nesher Ramla Homo, and even the first Homo sapiens. Thanks to advances in the application of genetic studies to the paleoanthropological record, we now know that interbreeding took place between several of the species known to have coexisted in Eurasia: humans, Neandertals, and Denisovans. Once again, the fossil evidence thus far does not support the hypotheses that these encounters involved warfare or other forms of violence. By around 150,000 years ago, at least six different species of Homo occupied much of Eurasia, from the Siberian steppes to the tropical Southeast Asian islands, and still no fossil evidence appears of large-scale interpopulational violence.
Some 100,000 years later, however, other varieties appear to have died away, and Homo sapiens became the only Homo species still occupying the planet. And occupy it they did: By some time between 70,000 and 30,000 years ago, most of the Earth’s islands and continents document human presence. Now expert in migrating into new lands, human populations flourished in constantly growing numbers, overexploiting other animal species as their dominion steadily enlarged.
Without written records, it’s impossible to know with any certainty what kinds of relationships or hierarchies might have existed during the final phases of the Paleolithic. Archeologists can only infer from the patchy remains of material culture that patterns of symbolic complexity were intensifying exponentially. Art, body decoration, and incredibly advanced tool kits all bear witness to socially complex behaviors that probably also involved the cementing of hierarchical relationships within sharply distinct social units.
By the end of the last glacial period and into the Neolithic and, especially, protohistoric times—when sedentarism and, eventually, urbanism, began but before written records appear—peoples were defining themselves through distinct patterns and standards of manufacturing culture, divided by invented geographic frontiers within which they united to protect and defend the amassed goods and lands that they claimed as their own property. Obtaining more land became a decisive goal for groups of culturally distinct peoples, newly united into large clusters, striving to enrich themselves by increasing their possessions. As they conquered new lands, the peoples they defeated were absorbed or, if they refused to relinquish their culture, became the have-nots of a newly established order.
An Imagined World
After millions of years of physical evolution, growing expertise, and geographic expansion, our singular species had created an imagined world in which differences with no grounding in biological or natural configurations coalesced into multilayered social paradigms defined by inequality in individual worth—a concept measured by the quality and quantity of possessions. Access to resources—rapidly transforming into property—formed a fundamental part of this progression, as did the capacity to create ever-more efficient technological systems by which humans obtained, processed, and exploited those resources.
Since then, peoples of shared inheritance have established strict protocols for assuring their sense of membership in one or another national context. Documents proving birthright guarantee that “outsiders” are kept at a distance and enable strict control by a few chosen authorities, maintaining a stronghold against any possible breach of the system. Members of each social unit are indoctrinated through an elaborate preestablished apprenticeship, institutionally reinforced throughout every facet of life: religious, educational, family, and workplace.
Peoples belonging to “alien” constructed realities have no place within the social unit’s tightly knit hierarchy, on the assumption that they pose a threat by virtue of their perceived difference. For any person outside of a context characterized by a relative abundance of resources, access to the required documents is generally denied; for people from low-income countries seeking to better their lives by migrating, access to documents is either extremely difficult or impossible, guarded by sentinels charged with determining identitarian “belonging.” In the contemporary world, migration has become one of the most strictly regulated and problematic of human activities.
It should be no surprise, then, that we are also experiencing a resurgence of nationalistic sentiment worldwide, even as we face the realities of global climate deregulation; nations now regard the race to achieve exclusive access to critical resources as absolutely urgent. The protectionist response of the world’s privileged, high-income nations includes reinforcing conjectured identities to stoke fear and sometimes even hatred of peoples designated as others who wish to enter “our” territories as active and rightful citizens.
Thanks to the very ancient creation of these conceptual barriers, the “rightful” members of privileged social units—the haves—can feel justified in defending and validating their exclusion of others—the have-nots—and comfortably deny them access to rights and resources through consensus, despite the denigrating and horrific experiences these others might have undergone to ameliorate their condition.
Incredibly, it was only some 500 years ago that an unwieldy medieval Europe, already overpopulated and subject to a corrupt and unjust social system, (re)discovered half of the planet, finding in the Americas a distinct world inhabited by many thousands of peoples, established there since the final phases of the Upper Pleistocene, perhaps as early as 60,000 years ago. Neither did the peoples living there, who had organized themselves into a variety of social units ranging from sprawling cities to seminomadic open-air habitations, expect this incredible event to occur. The resource-hungry Europeans nevertheless claimed these lands as their own, decimating the original inhabitants and destroying the delicate natural balance of their world. The conquerors justified the genocide of the Indigenous inhabitants in the same way we reject asylum seekers today: on the grounds that they lacked the necessary shared symbolic referents.
As we step into a newly recognized epoch of our own creation—the Anthropocene, in which the human imprint has become visible even in the geo-atmospheric strata of our planet—humans can be expected to continue creating new referents to justify the exclusion of a new kind of migrant: the climate refugee. What referents of exclusion will we invoke to justify the refusal of basic needs and access to resources to peoples migrating from inundated coastal cities, submerged islands, or lands rendered lifeless and non-arable by pollutants?