The Neolithic Age

The oldest stone tools in the archaeological record were made 3.3 million years ago in what is now northwestern Kenya.^[1] They are about 700,000 years older than the Oldowan tools, which had long been treated as the start of the stone tool record, and older than any known fossil of the genus Homo. The people who shaped them would be difficult for us to recognize as human in the modern sense.

The oldest known fossils of Homo sapiens come from Jebel Irhoud in Morocco and date to roughly 300,000 years ago. Their faces and teeth look modern, but their braincases are still longer and lower than ours.^[2] Between those two dates lies nearly the entire history of human tool use on Earth. What stands out about the 300,000 years that follow is how little changed for most of that time.

Around 7,000 BCE, the world's largest settlement held roughly 1,000 people. Writing did not exist. Cities did not exist. Yet humans already had modern brains, complex language, sophisticated tools, and thousands of years of agricultural experience. Why had civilizational development advanced so slowly relative to human capability? That is the central question Part 4 of this series sets out to answer.

Three Million Years of Tools

The Lomekwian tools from Kenya predate our genus. Homo habilis followed with the Oldowan tradition around 2.6 million years ago — stone cores and flakes, distributed across sites separated by thousands of miles and hundreds of thousands of years. Homo erectus carried tool use out of Africa into Eurasia.

What stands out in the Paleolithic (Old Stone Age) record is how slowly technology changed. Spanning roughly 3.3 million to 10,000 BCE, the Paleolithic covers most of human prehistory before agriculture, yet the basic toolkit remained remarkably stable across much of that period. Oldowan tools appear at archaeological sites separated by more than a million years. The evidence suggests that each generation often worked from much the same starting point, solving familiar problems without consistently building on the solutions developed by earlier generations.

Tool Use Is Not Uniquely Human

Most people assume that tool use is what makes humans distinctive. Studies of animal behavior show that tool use turns up in many unrelated species.

Ravens use objects as tools in at least eleven different ways, and sometimes make a tool by breaking off or trimming a piece of material.^[3] New Caledonian crows bend wire into hooks — a behavior that evolved independently of anything in the primate lineage. Bottlenose dolphins carry marine sponges to protect their beaks while foraging along the seafloor. Octopuses (Amphioctopus marginatus) carry coconut shell halves across open ground and assemble them into shelters.^[4] The octopus is a particularly striking example. Its evolutionary lineage diverged from that of vertebrates hundreds of millions of years ago, yet it has developed tool-related behaviors through an entirely independent evolutionary path.

The ability to use an object as a tool has evolved across a surprisingly wide range of nervous systems.

What distinguishes human technology is what the psychologist Michael Tomasello called the ratchet effect.^[5] Human cultural practices can accumulate improvements across generations. Each generation starts with what the previous one has learned: tools that have been refined through use, techniques improved through trial and error, and knowledge tested and corrected over decades or centuries. Tomasello's comparison is the chimpanzee. Chimpanzee groups have local tool traditions, e.g., fishing for termites with sticks. In his account, young chimpanzees mostly learn by watching what a tool does and then working out their own method. Because they don't copy the method itself, an improvement one chimpanzee makes tends to get lost before the next generation can build on it.

Human tool culture works differently. Each generation inherits a starting point that already incorporates the improvements of those who came before.

Over hundreds of generations, these gains compound, shaping technological progress far more than any individual act of tool use.

Language and the Ephemeral Record

Modern humans have language: a complex, syntactic system capable of expressing abstract thought and transmitting knowledge across generations. Archaeological evidence for behavioral modernity becomes widespread by around 50,000 years ago, during the Upper Paleolithic, and the biological capacity for language likely predates that period.

Language accelerates the ratchet considerably. A person can describe a technique they have never practiced, explain the reasoning behind a rule rather than simply pass on the rule itself, or tell someone about events that are past, distant, or hypothetical. Oral traditions can preserve substantial bodies of knowledge (including navigation, ecology, genealogy, and medicine) with considerable fidelity across generations.

But the medium is biological memory, and biological memory dies with the person who carries it. A failed experiment, forty years of astronomical observations, or the reasoning behind a disputed boundary can all be lost unless someone was present to hear and remember them. This constraint persisted throughout the roughly 250,000 years following the appearance of modern humans in the fossil record.

Agriculture and the Information Problem

Agriculture emerged around 10,000 BCE in the Fertile Crescent, marking the beginning of the Neolithic (New Stone Age) in that region. Hunter-gatherers had long tracked seasonal cycles: the movement of herds, the ripening of plants, and the arrival of rains. Agriculture did not create the need for this knowledge. It changed the consequences of getting it wrong.

When a food supply depends on planting at the right time and harvesting before the rains arrive, accurate seasonal knowledge becomes a matter of survival. The timing of solstices, the pattern of annual floods, and the temperature ranges required for germination all become critical variables. Knowledge that helped mobile foragers anticipate changing conditions became essential to farming communities that had invested in crops and could no longer simply move elsewhere when conditions turned against them.

Agriculture also generates a coordination problem that scales with population density. A group of thirty people coordinates through direct communication and shared memory. A community of several hundred needs to track land rights, stored grain, seasonal labor obligations, and transactions between households.

The demand for information grows faster than the population.

Together, these pressures (the need for reliable seasonal timing and the growing demands of economic coordination) created a problem that would shape technological development over the next several thousand years.

The Challenge of Persisting Knowledge

Around 7,000 BCE, during the early Neolithic, the world's largest settlement held roughly 1,000 people. Modern humans had existed for close to 300,000 years, and agriculture had been underway for roughly 3,000 years. The biological and cognitive capacities needed to build complex civilizations were already in place.

Yet the archaeological record shows no cities or writing, and little evidence of systems for preserving accumulated knowledge beyond the lifetimes of those who held it in memory. Somewhere in the roughly 4,000 years between early agriculture and the emergence of the first urban centers lies the answer. It begins with how communities learned to record and preserve what they knew.

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References

1. Harmand, S., Lewis, J. E., Feibel, C. S., Lepre, C. J., Prat, S., Lenoble, A., Boës, X., … Roche, H. (2015). 3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya. Nature, 521, 310–315.
2. Hublin, J.-J., Ben-Ncer, A., Bailey, S. E., Freidline, S. E., Neubauer, S., Skinner, M. M., Bergmann, I., Le Cabec, A., Benazzi, S., Harvati, K., & Gunz, P. (2017). New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens. Nature, 546, 289–292.
3. Jacobs, I., & Osvath, M. (2023). Tool use and tooling in ravens (Corvus corax): A review and novel observations. Ethology, 129(3), 169–181. DOI: 10.1111/eth.13352
4. Finn, J. K., Tregenza, T., & Norman, M. D. (2009). Defensive tool use in a coconut-carrying octopus. Current Biology, 19(23), R1069–R1070. DOI: 10.1016/j.cub.2009.10.052
5. Tomasello, M. (1999). The human adaptation for culture. Annual Review of Anthropology, 28, 509–529. DOI: 10.1146/annurev.anthro.28.1.509