A new paper on ancient humans points to the beads found in the Blombos cave in South Africa dating from about 75,000 years ago. They were fashioned from marine shells and perforated for stringing, likely with bone awls or crab claws. The authors ask, what can we infer from such finds about the minds of our ancient ancestors?

Generally, beadcraft, which later featured in trade across Africa, is thought to show modern human behavior.

After all,

According to one influential team of archaeologists, an assemblage of 41 perforated Nassarius kraussianus shells (Figure 1) uncovered at Blombos Cave, South Africa—and dated to roughly 75,000 years ago—are evidence of modern symbolic behavior and fully syntactic language (Henshilwood et al., 2004; see also d’Errico et al., 2005; Henshilwood & Dubreuil, 2009, 2011). We’ll follow their reasoning and use it to analyze inferences in cognitive paleoanthropology. Henshilwood and colleagues begin by demonstrating that the shells were beads; they were strung and worn as personal adornments. This involves ruling out alternative explanations of the shells’ deposition (behavior of natural predators, accidental human transport, etc.). Blombos Cave is many kilometers away from where the snails lived, and the collection contains only mature adult shells rather than a naturally occurring age range. Thus, deliberate collection and transportation are extremely likely. Microscopic analysis of the shells distinguishes their perforations and other modifications (e.g., flattened facets) from naturally occurring patterns. Their profile is consistent with the friction expected from beads: rubbing against thread, clothes, and other shells. Replication experiments with simulacra of bone tools utilized by the inhabitants of Blombos Cave produced similarly perforated shells. Additionally, ochre residues were detected, revealing that the beads, or the materials they were rubbing up against, were colored a striking red.

Adrian Currie, Anton Killin, Mathilde Lequin, Andra Meneganzin, Ross Pain Past materials, past minds: The philosophy of cognitive paleoanthropology Philosophy Compass First published: 18 June 2024 https://doi.org/10.1111/phc3.13001 Open access.

What can — and can’t — we infer from a find like this?

This type of reasoning is called minimum capacity inference and it is part of a newer discipline called cognitive paleoanthropology — the attempt to understand what was going on in the minds of ancient humans. The researchers infer not only that the Blomberg Cave dwellers were capable of symbolic thought but also that they had syntactic language (language with grammar). For example, “If symbolic behavior is necessary (or very likely necessary) for bead production and adorning use, and if we can show that the Blombos Cave beads are adornments, then they are strong evidence for symbolism as well. If such links can be forged between material remains and cognitive capacities, then they can be used to piece together a picture of our cultural and cognitive evolution.” They admit that this type of interpretation may be “extremely complex.”

For one thing, researcher Rudolf Botha has come forward to disagree. He argues that “that the inferential step from symbolic behaviour to modern language lacks the required warrant.”

After all, as Currie et al themselves admit,

Perforated shells don’t equal beads (they could have been manufactured for other purposes), beads don’t equal symbolically mediated behavior (they could index group membership), and symbolically mediated behavior doesn’t equal syntax. Considered in isolation, Henshilwood and colleagues’ interpretation of personal adornments as straightforward proxies for symbolically mediated behavior reflected what was then a common (though not uncontroversial) assumption about what prehistoric ornamentation reveals, or very likely reveals, which Botha challenged.

Currie et al., Past materials, past minds

Image Credit: Natael - Adobe Stock

Ah, but as they also go on to point out,

However, when not considered in isolation, but as part of a larger repertoire of materials associated with ancient humans—musical instruments, statuettes, and cave paintings, for example—the shell beads, ochre, and other traces of Paleolithic personal ornamentation highlight the deep importance of (let’s call it) “proto aesthetics” to the human lineage. The time and effort ancient foragers invested into collecting, transporting, and modifying the materials (time that could have been spent on more utilitarian pursuits) demands explanation. Beads, in the absence of other signals of symbolism, are one thing; the absence of symbolic thinking is harder to maintain when those beads are combined with traces of many other potentially symbolic behaviors … If this holds, demonstrating a fairly strict connection between beads, adornment, and symbolism becomes somewhat less of a requirement for licensing the inference (especially in light of the increasingly complex picture of human evolution, see below).

Currie et al., Past materials, past minds

In short, participation in a pattern gives strength to an inference — in this case, a design inference: The beadcrafters were capable of symbolic thought.

But can we infer that they used language?

A critical question that remains is whether we can assume that a culture that prized beadwork must also have had language. Tools, for example, have been found from about 3.3 million years ago. But, until people started writing things down, language was written on air. Oral recitation of history and scripture is probably very old but, if the text did not die with the orator, it died with the language. The mystery remains.

It’s a sign of progress, perhaps, that researchers are defending the role of parsimonious inference. It’s possible to see too much in a scattering of beads — but it is also possible to see too little.

You may also wish to read: The human mind has no history. There is no good reason to assume that human intelligence evolved from mud to mind via a long slow history. When we look at the human past, we see lights flashing on suddenly. Technology evolves but not the mind as such.