Ancient human relative used fire, discoveries suggest | Hacker News Reader

Ancient human relative used fire, discoveries suggest

washingtonpost.com

89 pointsbenbreen50 comments

I'll believe it when they release geochemical data for the soot and plot the locations of the "hearths" on the cave map. Where is the published peer reviewed paper associated with this announcement?

This discovery was made in 2013, in a cave that was believed by the SA caving community to be well understood. Where are the hearths they claim to have found? Why did nobody in the previous 9 years of exploration and decades of caving see this? What makes them certain these are not carbide dumps from humans in the last 50 years? [1] Or organic matter that may have fallen from roof cracks? Also, what has happened to the 1500 bone fragments they have excavated

Baboons in modern times are known to navigate caves without fire [2], the paleoanthropology community should still consider the possibility that H. Naledi had no need for light to place their dead these caves.

[1] https://en.wikipedia.org/wiki/Carbide_lamp [2] https://www.youtube.com/watch?v=9letjf7ZZGA

Yeah, I'm very skeptical. Just the decision to announce this by press release rather than peer reviewed paper suggests there are a lot of uncomfortable questions, similar to what you raised, that the authors are trying to avoid.

Berger's been taking some heat on Twitter where he announced this [1]. Apparently he considers a public-interest lecture and a publicity tour equivalent to a preprint on something like SSRN. Can't say I agree, but it seems to have been effective in getting people to talk about it.

[1] https://twitter.com/LeeRberger/status/1599965297993129984?s=...

I mean he's kind of right. A preprint is just a badly formatted blog post published in a pdf. Until its finished and published. At least if one see peer-review journal literature as the gold standard of scientific discourse. Maybe this Berger thing has more to it, but scientists can (and maybe even should) talk about their ongoing research before there is a paper behind it.

It's not the public awareness stuff that I'm concerned about. That's just a necessary fact of life that I've also been involved with on my own digs.

I'm personally simply skeptical that the research conditions necessary to make a Netflix special (premiering in May-June apparently) are also conducive to high quality academic work.

Publishing a preprint goes partway to addressing that by showing everyone where their results will fit into the existing literature and strengthen the published paper by hearing / addressing public criticisms before they actually publish.

> he's kind of right. A preprint is just a badly formatted blog post published in a pdf. Until its finished and published

No, it has empirical data, most importantly, and also methods, analysis, conclusions, citations. It's nothing like a blog post, or another way of looking it it - it is an extraordinary blog post.

Oh yeah all those things have never been seen in a blog post. But you are missing the point.

Twitter - that's become the perfect venue for this kind of thing, but not in the way Berger imagines.

> he considers a public-interest lecture and a publicity tour equivalent to a preprint on something like SSRN

There's all the difference in the world: A preprint has empirical data (not to mention an hypothesis, methods, analysis, conclusion).

> it seems to have been effective in getting people to talk about it

That has nothing to do with science. No scientific advance is connected to the public talking about it.

Being skeptical makes sense. Abandoning science is less of an obvious step. This consists primarily of some initial observations and speculations being shared. These could potentially lead to a testable hypothesis which could then in time lead to a published peer reviewed paper. Initial observations and speculations never lead directly to published peer reviewed papers in the short term because those require work to prepare and verify. That you are responding to some initial observations and speculations with demands for a published peer review paper indicates that you lack interest and understanding in the actual work of science. If you really are not engaged then maybe it would make more sense to allow others to investigate findings to see if they are truly interesting and perhaps could lead to robust results.

If any skeptic here likes nature documentaries, I'd recommend "Our Great National Parks" on Netflix. I found it unique in that it documented exceptionally intelligent and complex behavior by a number of animals we don't normally consider as being intelligent. For example, tool use by mongooses (cracking a snail shell with a rock) and a monkey riding a deer for fun, as well as frequent cooperation between species.

I don't find it so difficult to believe that a slightly larger encephalization quotient than our nearest competitors (chimps) could lead to an ability to control fire.

I love nature documentaries, I'll have a look at that one!

I agree, lots of animals use tools in one way or another. Starting or even just controlling a chemical reaction does seem like a big step above mechanical methods though. I wouldn't really be that surprised overall if we eventually discover that H. Naledi or other hominids had some control of fire. I will be surprised if the Dinaledi site turns out to be the first evidence of it

> a monkey riding a deer for fun

I used to have a neighbour with a goat and chickens, and at least one of the chickens would ride around on the goat's back. There are a decent number of YouTube videos of other chickens riding goats, so it seems fairly common.

> we don't normally consider as being intelligent

I'm curious what "we" you refer to, because I've seen years of articles about tool use and play and intelligence across all sorts of mammals and birds.

> the possibility that H. Naledi had no need for light to place their dead

There are also sources of light other than fire, such as bio-luminescence.

Are there many bioluminescent creatures in North-Central South Africa?

One million years ago, I don't know. Also bio-luminescent fungi are a possibility.

Be careful, there were distinct developmental steps:

opportunistically using fire

keeping and transporting fire

making fire, intentionally and controlled

the last step may have been discovered only in the last 10-100000 years, expert opinions diverge a lot here

No way this is true. This would mean humans domesticated animals and began to develop farming before (or right as) they discovered how to make fire.

A big reason humans developed our modern brains ~35kya is because of them cooking food (which makes digestion on proteins easier on the stomach)

Instead of speculating based on ignorance - which traps us in a loop of our own ignorance, and of each other's ignorance - let's break out of that loop and check with someone who has seen the evidence and knows it well:

* Fire use: ~1.42 million years ago is estimate, but uncertain

* Homo sapiens: Estimates range from 160,000 - 315,000 years ago.

* Controlled fire use: ~9,000 years ago; also uncertain

https://www.britannica.com/topic/Homo-sapiens

https://www.britannica.com/science/fire-combustion

Tip: If Britannica gives you a paywall, find the article via a search engine. Or maybe pay them - it's nice to have experts at your fingertips. The Homo Sapiens article is by the Curator of the Department of Anthropology at American Museum of Natural History.

Are you missing a zero? Anatomically modern humans are significantly older than 35,000 years.

It's plausible that a larger brain developed because it offered advantages. But later that brain was optimized without increasing in size.

For example, my current desktop computer is the same size as my stone age IBM PC.

There’s a reason we call them anatomically modern and not just humans. There is a period ~35kya where we get “Modern man” and it correlates with increased brain activity.

Things like “complex” cave paintings, tally marks etc take off right after (in evolutionary terms) as we marched towards farming and the written word

I do believe that "anatomically modern" includes brains. https://en.wikipedia.org/wiki/Brain_size#Variation_and_evolu...

Can you provide any sources for claims about brain size? I admit I'm not an expert, but I've never heard claims that brain size significantly increased in that period.

A few other facts that I can't say rule out what you're saying, but make it counter-intuitive:

Mitochondrial Eve was 150,000 years ago, Y Chromosome Adam was > 200000 years ago. Aboriginal populations in Australia are descended from populations that reached the island close to 50000 years ago. The Bering Strait was crossed close to 20000 years ago.

P.S. I do agree that saying fire might've been discovered within the past 10,000 years is unbelievable.

Edit: I belatedly see you might be talking about other changes to brains that aren't associated with increased brain size. Still, I'd ask whether there's evidence that anything about our brains changed 35,000 years ago, as opposed to us having accumulated knowledge and culture over time.

> A big reason humans developed our modern brains ~35kya is because of them cooking food (which makes digestion on proteins easier on the stomach)

Probably a bizarre question/thought experiment , and no way we'll know in our lifetime - if we start feeding cooked food to some animal, will it develop a larger brain?

Only if it _needed_ a larger brain to get that cooked food. Humans feed cooked food to ourselves, and our big brain helps us to discover and remember new sources of food, and how they need to be treated to become edible (e.g., https://en.wikipedia.org/wiki/Cassava#Toxicity). Without this pressure it’s hard to see how plentiful, nutritious food would do anything other than make the animal sedentary, slow, and stupid (e.g., to one degree or another, koalas, sloths, gorillas, modern humans).

No, there has to be selective pressure if we're not just talking about random drift. For hominids, sophisticated brains have been an incredibly rewarding evolutionary strategy despite the staggeringly expensive energetic costs they incur. Foraging is an intellectually demanding activity as we do it, so anything evolution can do from minimizing other expensive tissues (expensive tissue hypothesis) to high calorie oriented food selection to prosociality feeds back into improving fitness.

The timeline is pretty suspect there though. 35kya is far, far too late for any sort of behavioral modernity as that term is typically used.

My guess is that it would depend on the animal. Most carnivore stomachs are highly optimized for digesting raw meat. My layman's understanding is that because humans are fairly balanced omnivores, we get more benefit from cooking meat.

The pH of human stomach acid is on par with that of many scavengers, such as vultures.

Anthropological evidence indicates that early hominids, as they began their transition to a more carnivorous diet, were feeding on the left overs from other carnivorous predators - which would explain the need for such an extremely acidic stomach

Fascinating, does that mean vultures are just as susceptible to e.coli, salmonella, etc as we are? I always presumed they could handle "slightly spoiled" meat without food poisoning better than us.

Interesting!

perhaps (and i don't know) the added nutrition from eating cooked food had greater benefit at time T for individuals with slightly better brains via natural variation a la genetics/mutation...and if so they'd slightly be more active and slightly be more reproductive, correlating advent of cooked food with improving brains, but not as causally as suggested?

Just the timeline given here is very suspect, my understanding is human brains were roughly the same size they are today 35000 years ago. Did you mean 350k?

Has the causal and temporal relationship between cooking and modern brain development been firmly established? The last time I looked into the literature I could find (a decade ago), there seemed to be a tantalizing correlation but enough noise in the timing of cooking to place it well short of being an well-accepted theory. And the question of what constitutes a "modern brain" and when our ancestors had it was an even fuzzier area.

A lot of these things we don't have accurate timelines for because they're all pre-history. We find evidence of things, but no records.

keeping fire alive was a real thing way before making it ex nihili. so this wouldn't contradict the correlation with brain size. if it went or you could get it from your neighbor or long distance transport from natural sources.

is there a citation for that? i don't mean i think it's wrong, just want to learn more why you said that.

> 10-100000 years

I'm confident it was more than 10 years. :-P

Of course they did, even birds use fire [0]

[0] https://wildlife.org/australian-firehawks-use-fire-to-catch-...

Is this that surprising? There was certainly lava in those times. Lightning strikes, bushfires. Any intelligent creature would be aware of the phenomenon and would be able to use it.

Lava is a very rare occurrence, the vast majority of all pairs of eyes that have ever lived have never seen any. And intelligent awareness of fire is hardly an inevitable path to utilization, individuals might just as well use all that to keep a safe distance. I guess what I'm trying to say, to my own surprise I might add, is that the key evolutionary requirement for for utilization is perhaps not so much intelligence, but a mating process involving a certain element of bravado.

Over the span of thousands of years and many many of these beings, it only takes a few to witness lava and learn about it. It's like ants finding sugar. Give it time and they'll come across it and then the whole nest will know about it fairly quickly.

How many places do accessible pits of lava even exist? Isn't it rare enough that you'd have to live in exremely few places for that information to even be helpful?

The surprising bit seems to be that this ancestor had a much less developed brain (according to the article, a brain the size of an orange). Besides that, the importance is that it further pushes back the point where our ancestors initially learned to harness fire.

Plus, I think this might demonstrate a bit more advanced thinking than expected because they would've been using these fires to light the path into apparently fairly dangerous caves. Suggesting planning ability and some amount of comfort making and manipulating fire.

Seeing how unnecessarily intelligent the human brain is, for most environments, I would be more surprised if earlier humans (maybe later than these) didn't use fire than if they did. It's very doubtful that there was some step function in intelligence, to make that possible, since step functions are extremely rare in evolution.

The "unnecessarily intelligent" nature of a lot of humans was something I was thinking about too. For example, crows obviously have significantly smaller brains, yet demonstrate enough intelligence for at least basic tool use. So, in a biological sense it shouldn't be too surprising to find fire use at that point in evolution.

But perhaps it's more interesting because of how that would relate to human level intelligence in general. If they were capable of manipulating fire and were capable of enough planning to use them to maintain a path within a deep cave, they would probably have had some ability to communicate as well.

In which case, was our larger brain mass due to it simply not being enough of a detriment to survival or was there some big cognitive difference between these ancestors and modern humans that was also so much more advantageous to lead to our much larger brains?

Yes, step functions don't really exist in evolution, but even for gradual changes it's worthwhile to understand why we specifically were successful in comparison to others which seem to meet the requirements we think might be important.

Black Kites will carry burning twigs and fly them elsewhere to spread fire and force prey into the open.

Consider fire for light vs. warmth vs. cooking vs. ritual vs. safety vs. hunting.

One hypothesis: They lit fires to scare out bats to eat, possibly catching them in nets at the cave mouth. After decimating the population, they were forced to push deeper in to the cave system.

I would really like to plat a RTS game where instead of wizards it is homonid evolution

off topic, but the title made me think of my dad with the Weber charcoal grill, instead of last decades of microwave for most everything

> Ancient human relative used fire, discoveries suggest

and the wheel.

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