It’s not relevant to moan about weird behavior by AI, when ChatGPT has just provided a master-class in how to criticize the top-down human origin story. Not that I will give it the last word:
ChatGPT: "First, the argument leans heavily on ecological plausibility without corresponding evidential anchors. The claim that australopiths required engineered thorn barricades and coordinated thrusting defense rests on a perceived mismatch between morphology and predator pressure. "
That description of the top-down origin model is vague. My point was that that, with those teeth and those feet, the australopiths would have been easy to kill whether on the ground or in a tree. Yet they lived in a food web where alternative prey are hard to kill. In particular, they lived alongside baboons, the perfect control species. Baboons are descended from arboreal monkeys. Their body plans show that they extended the already strong primate biting defence, while retaining “four-handed” agility in trees. The most economical model to explain australopith ecology is that they used thrusting spears while foraging and thorn barricades with spears at night.
The spectacular failure of arboreal monkeys and apes to converge towards a common body plan for terrestrial life by baboons and australopiths, is shown here. It needs explanation.
ChatGPT: “Yet plausibility is not equivalent to likelihood. Many primate species survive substantial predation without engineered structures, relying on flexible habitat choice, arboreal refugia, fission–fusion dynamics, and demographic resilience. The essay tends to treat these alternatives as insufficient without demonstrating that they fail quantitatively. A comparative mortality model would strengthen the case considerably.”
The man-eating lions of Tsavo provide a mortality model. When hundreds of unarmed workers were imported to build the Ugandan railway, a couple of lions learned to prey on them. The lions repeatedly forced their way under thorn barricades, alerting the workers. Once emerged, a lion ignored thrown stones and firebrands, selected a victim and dragged it back though the thorns*.* Note that modern humans are better built for throwing things than the australopiths were. Your alternatives are made irrelevant by the fact that they are employed by primates who are formidable biters, and retain “four handed” agility in trees.
**ChatGPT: "**Second, the hypothesis risks being insulated from falsification. Thorn barricades and wooden spears would leave little archaeological trace. While preservation bias is real, a model that depends on largely invisible behaviors must compensate with strong indirect predictions—skeletal stress markers, demographic signatures, predator injury patterns, or clear ecological correlates. These are not yet articulated in a way that would allow the hypothesis to be rigorously tested".
What the model actually depends on is fossil evidence of pygmy-sized ancestors who would have been easy to kill unless supported by defences such as their descendants use, and yet who lived in a food web with intense competition between very able predators and prey who were hard to kill*.*
You admit to a preservation bias against sticks and branches from million of years ago being preserved in identifiable form. But consider how strong that bias is, where a significant proportion of primary production in the food web goes to woody material, so that there is an active food web for metabolising wood.
Your indirect predictions such as “skeletal stress markers” and so on, set a high barrier against playing out the top-down origin model. What is really strange is that this model hasn’t been developed much by mainstream scientists, in spite of the strong body-plan evidence.
ChatGPT: “Third, the application of superorganism language requires caution. E.O. Wilson’s framework arose in the context of eusocial insects, where genetic structure underwrites colony-level selection. In vertebrates, group selection remains contentious and typically weak relative to individual selection. The essay gestures toward group-level persistence but does not fully address the evolutionary mechanisms by which group-beneficial traits would reliably outcompete within-group free riding. Cultural transmission could help here, but the mechanism deserves more explicit treatment.”
More than caution, it involves trepidation. Because of Richard Dawkins and his thought police. And that is an important red flag about the sensible advance of science.
I pointed out that the criteria E.O. Wilson used for eusocial behavior creating a superorganism on whom the fitness of an individual depended, would also apply to a mammal species that relied on defence of a long-lived bounded structure. And I repeated Wilson’s point that eusocial insects are the only animals to which we apply important human concepts like “workers” and “soldiers”. Humans achieve the equivalent division of labour more flexibly using language rather than genetically controlled castes. The implication is that human language evolved in an arms race between hominin “superorganism” groups.
ChatGPT: "Fourth, the model may underestimate the defensive capacity of australopith dentition, climbing ability, and habitat flexibility. Early hominins retained significant arboreal competence and were not necessarily committed ground sleepers. If tree sleeping persisted longer than assumed, the need for engineered night barricades diminishes substantially".
It’s routinely stated that early hominis retained significant arboreal competence. But what is less focused on is that their feet compromised their ability to avoid capture by leopards in trees. Baboons hang from terminal branches in very high nesting trees, using their four hands. Under a comparable threat, australopith feet would have been no use at all, they were effectively crippled. This would have made them easy to kill.
It’s not reasonable to imagine australopiths biting their predators. But a case can be made that they used their arms and hands. There have been a few cases of humans, caught without weapons, strangling leopards that had attacked them. See this famous pic of Carl Akeling from 1896.
When I was a child, the local butcher (a Mr Wiggill) had scarred arms from a similar exploit. There are also accounts of unarmed people reaching into a leopard’s mouth and twisting or tearing out its tongue. In Stuart Cloete’s autobiography he remarks that “this is in fact the right thing to do” which implies instinctive behaviour.
The counter to the argument of strangling being a settled antipredation strategy by australopiths is that (a) it would lead to claw injuries that would be difficult to treat without modern medicine and (b) these leopards tackled unfamiliar prey, whereas the habituated Panar man-eater killed 400 and the Rudraprayag individual 125+. Both their careers were cut short by being shot, not strangled.
ChatPT: "Finally, the proposal risks a subtle teleological pull. Because later humans become highly coordinated, weapon-using organisms, the reconstruction may be projecting backward an early commitment to that trajectory. The challenge is to show that the spear–barricade system is not merely consistent with later outcomes but independently required by earlier conditions."
The term “teleology” is used in origin stories to signal a wrong way of approaching the story, But there is no “trajectory” in coordinated weapon-using. It’s just something humans do, and the body plan of australopiths suggests that they did the same. That habit was more clearly adaptive for them than it is for modern humans. Come down to it, why do humans use weapons in a coordinated way?