The collection of 27 bones, now fossilized, that had been fashioned into hand tools has certainly upended tidy theories of gradual human mental development:

Early human ancestors known as hominins (human ancestors who could walk upright) had already been making tools out of stone in some capacity for at least a million years, but there’s been scant evidence of widespread toolmaking out of bones before about 500,000 years ago.

The hominins who shaped the recently-discovered bone tools did so in a manner similar to how they made tools out of stone, by chipping away small flakes to create sharp edges — a process called ‘knapping’…

Co-author Dr Renata F. Peters (UCL Archaeology) said: “The tools show evidence that their creators carefully worked the bones, chipping off flakes to create useful shapes. We were excited to find these bone tools from such an early timeframe. It means that human ancestors were capable of transferring skills from stone to bone, a level of complex cognition that we haven’t seen elsewhere for another million years.”

University College London. “Prehistoric bone tool ‘factory’ hints at early development of abstract reasoning in human ancestors.” ScienceDaily, 5 March 2025.

The shaped bones were mostly the strong limb bones of hippos and elephants, possibly used for processing animal carcasses.

From stone to bone

The researchers offer some background:

The bone tools reported in this study were from the time that the ancient human ancestors were progressing into the “Acheulean” age which began as far back as about 1.7 million years ago. The Acheulean technology is best characterised by the use of more intricate handaxes that were carefully shaped by knapping — allowing the production of tools through more standardised means.

The bone tools show that these more advanced techniques were carried over and adopted for use on bones as well, something previously unseen in the fossil record for another million years, much later into the Acheulean age.

Prior to this find, bones shaped into tools had only been identified sporadically in rare, isolated instances in the fossil record and never in a manner that implied that human ancestors were systematically producing them. “Abstract reasoning”

But how uncommon were such “bone tool factories” really?

True, researchers have only found one. But it’s helpful to keep in mind that the vast majority of human beings who lived during the subsequent million years have lived and died without leaving any record of their existence. We really don’t know what they were doing, let alone thinking. Thus, a single find like this one may challenge widely accepted theories. Perhaps it’s best if the theories are only lightly held in the first place.

From the open-access paper:

Before our discovery, bone artefact production in pre-Middle Stone Age African contexts was widely considered as episodic, expedient and unrepresentative of early Homo toolkits. However, our results demonstrate that at the transition between the Oldowan and the early Acheulean, East African hominins developed an original cultural innovation that entailed a transfer and adaptation of knapping skills from stone to bone. By producing technologically and morphologically standardized bone tools, early Acheulean toolmakers unravelled technological repertoires that were previously thought to have appeared routinely more than 1 million years later.

Ignacio de la Torre, Luc Doyon, Alfonso Benito-Calvo, Rafael Mora, Ipyana Mwakyoma, Jackson K. Njau, Renata F. Peters, Angeliki Theodoropoulou, Francesco d’Errico. Systematic bone tool production at 1.5 million years ago. Nature, 2025; DOI: 10.1038/s41586-025-08652-5

Why new technologies can be very slow to get started

While this find suggests that very ancient humans were capable of abstract thought, it also shows that abstract thought, all by itself, did not rapidly lead to many further advances.

One reason for that might be that many technologies can’t get started until a fundamental underlying technology is developed. It’s not because humans are not smart enough to think of the idea.

For example, most new technologies depend on metals at some point. But metallurgy starts with mining, which itself requires the development of tunnel technologies. The earliest mines must have been constructed largely without metal tools because troves of metals deep underground were precisely what the miners didn’t have and thus were seeking. And next comes the development of smelting and refining… The more such technologies exist, the faster the development, because the technologies complement and assist each other. But perhaps we should not be surprised that the development is very slow at first.

In the same way, the capacity for abstract thought enables us to imagine flying to the moon. So legends from around the globe tell us of such feats and have probably done so from time immemorial. But literally going to the moon requires technologies that were not available before the mid-twentieth century.

It does not require the development of a greater capacity for abstraction than before. The evolution was in the technology, not the mind.

Did humans ever not have the capacity for abstract thought?

As paleontological discoveries that show evidence of abstract thought get pushed back further into human history, the question naturally arises, was the normally developed human mind ever incapable of abstract thought? Approved theories of human evolution assume so. They need such a human. For want of evidence, for quite a while, Neanderthal man was forced into that role. Eventually, the keepers of his legacy rebelled.

So where are we now? So far we have found cultures that are slow to change but we haven’t found the unthinking human. And we are getting deeper and deeper into the past. At some point the evidence is going to demand an accounting from the theory.