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[link] Back to the trees

85 Post author: Konkvistador 04 November 2011 10:06PM

So we say we know evolution is an alien god, which can do absolutely horrifying things to creatures. And surely we are aware that includes us, but how exactly does one internalize something like that? Something so at odds with default cultural intuitions. It may be just my mood tonight, but this short entry on the West Hunter (thanks Glados) blog really grabbed my attention and in a few short paragraphs on a hypothesis regarding the Hobbits of Flores utterly changed how I grok Eliezer's old post.

There is still doubt, but there seems to be a good chance that the Flores Hobbit was a member of a distinct hominid species, rather than some homo sap with a nasty case of microcephalic dwarfism.   If this is the case, the Hobbits are likely descended from a small, Australopithecus-like population that managed to move from Africa to Indonesia without leaving any fossils in between, or from some ancient hominid (perhaps homo erectus) that managed to strand themselves on Flores and then shrank, as many large animals do when isolated on islands.

Island dwarfing of a homo erectus population is the dominant idea right now.  However, many proponents are really bothered by how small the Hobbit’s brain was.  At 400 cc, it was downright teeny, about the size of a chimpanzee’s brain.  Most researchers seem to think that hominid brains naturally increase in size with time. They also suspect that anyone with a brain this small couldn’t be called sentient – and the idea of natural selection driving a population from sentience to nonsentience bothers them.

They should get over it.  Hominid brain volume has increased pretty rapidly over the past few million years, but the increase hasn’t been monotonic.  It’s decreased about 10% over the past 25,000 years. Moreover, we know of examples where natural selection has caused drastic decreases in organismal complexity – for example, canine venereal sarcoma, which today is an infectious cancer, but was once a dog.

I have to break here to note that was the most awesome fact I have learned in some time.

There is a mechanism that might explain what happened on Flores – partial mutational meltdown.  Classic mutational meltdown occurs when a population is too small for too long. Selection is inefficient in such a small population: alleles that decrease fitness by less than 1/N drift fairly freely, and can go to fixation.  At the same time, favorable mutations, which are very rare, almost never occur.  In such a situation, mutational load accumulates – likely further reducing population size – and the population spirals down into extinction. Since small population size and high genetic load increase vulnerability to disaster, some kind of environmental catastrophe usually nails such doomed, shrinking populations before they manage to die off from purely genetic causes.

In principle, if the  population is the right size and one adaptive function is considerably more complicated than others, presenting a bigger mutational target,  you might see a population suffer a drastic decline in that function while continuing to exist. There is reason to think that intelligence is the most complex adaptation in hominids. More than half of all genes are expressed in the brain, and it seems that a given degree of inbreeding depression – say cousin marriage – depressesIQ more than other traits.

Flores is not that big an island and the population density of homo-erectus type hunter-gatherers must have been low – certainly lower than that of contemporary hunter-gatherers, who have much more sophisticated tools.  Thus the hobbit population was likely small.  It may not have been possible to sustain a high-performing brain over the long haul in that situation.  Given that their brains performed poorly – while the metabolic costs were as high as ever – selection would have shrunk their brains.  Over hundreds of thousands of years, this could well have generated the chimp-sized brain we see in the LB1 skeleton.

Of course, this could only have happened if there was an available ecological niche that did not require human-level intelligence.  And there was such an opening: Flores had no monkeys.

That last sentence just struck me with utter horror.

Comments (40)

Comment author: [deleted] 04 November 2011 10:57:21PM *  14 points [-]

They also suspect that anyone with a brain this small couldn’t be called sentient – and the idea of natural selection driving a population from sentience to nonsentience bothers them.

I'm a little confused by this use of the word sentient. I understand it to mean "qualia-bearing", and I believe that chimps and other animals probably have qualia. Perhaps they meant that it probably didn't have our depth of human experience, i.e. it probably had a similar degree of consciousness (or qualia) to a chimp.

Incidentally I am reminded of the disturbing science fiction novel Blindsight by Peter Watts, which explores (fictional insight only, of course!) similar ideas.

canine venereal sarcoma, which today is an infectious cancer, but was once a dog.

This is now my favourite fact.

That last sentence just struck me with utter horror.

It's the same kind of horror one feels after reading Eliezer's "Beyond the reach of God". I'd love to know what the neurological difference is between knowing something on a surface level, and actually internalising it such that the full horror of it is felt.

Comment author: Desrtopa 04 November 2011 11:16:29PM 17 points [-]

I'm a little confused by this use of the word sentient. I understand it to mean "qualia-bearing", and I believe that chimps and other animals probably have qualia. Perhaps they meant that it probably didn't have our depth of human experience, i.e. it probably had a similar degree of consciousness (or qualia) to a chimp.

I suspect that it's simply down to sentient vs. sapient being one of the most common word confusions in the English language.

Comment author: Nornagest 04 November 2011 11:25:47PM 10 points [-]

canine venereal sarcoma, which today is an infectious cancer, but was once a dog.

This is now my favourite fact.

Kind of throws the Azathoth metaphor into stark relief, doesn't it?

Comment author: pedanterrific 06 November 2011 05:04:03AM 24 points [-]

I have no mouth, and I must bark.

Comment author: FiftyTwo 18 January 2012 10:32:35PM *  7 points [-]

Incidentally I am reminded of the disturbing science fiction novel Blindsight by Peter Watts, which explores (fictional insight only, of course!) similar ideas.

I just read through that in one long sitting, profoundly existentially terrifying and disturbingly enthralling. Excellent book, but, irrationally, I really hope there's a good counter-argument to it somewhere.

Shiver. I need some chocolate now.

Edit Ended up watching "My little pony," the perfect anti-despair superstimulus. Thinking about it further I suspect theres something to be said in favour of self-awareness in terms of type one and type two processes, self awareness being energy expensive but actually making better decisions, but I don't know enough cognitive science to be sure.

Comment author: gwern 04 November 2011 11:11:48PM 4 points [-]

I'd love to know what the neurological difference is between knowing something on a surface level, and actually internalising it such that the full horror of it is felt.

Near vs Far?

Comment author: lukeprog 05 November 2011 08:56:27PM 5 points [-]

That's probably part of it. Here is a recent paper on the neuroscience of Near vs. Far (aka construal level theory).

Comment author: atucker 05 November 2011 01:54:09AM 1 point [-]

I'm a little confused by this use of the word sentient. I understand it to mean "qualia-bearing", and I believe that chimps and other animals probably have qualia.

Not all creatures with Qualia are self-aware, and I suspect that that's the property he's trying to talk about.

Dogs feel loyalty, but they don't necessarily know that they do. That is to say, if you somehow got a dog to talk, it wouldn't necessarily start talking about it's feeling towards others, or its thought processes.

Comment author: Grognor 05 November 2011 02:40:34AM 9 points [-]

Far Side on the subject.

Comment author: Logos01 05 November 2011 01:47:32AM 1 point [-]

canine venereal sarcoma, which today is an infectious cancer, but was once a dog.

This is now my favourite fact.

Fascinating conjecture; what path of history would be required for that strain of organisms to develop into a tool-manufacturing multicellular organism?

Comment author: DanielVarga 06 November 2011 05:16:33PM 10 points [-]

what path of history would be required for that strain of organisms to develop into a tool-manufacturing multicellular organism?

The first, hard step on that path would probably be surviving outside dogs. At least, I don't want to think about paths that miss this step.

Comment author: Konkvistador 06 November 2011 08:58:24PM *  10 points [-]

They seem more probable though. How familiar are you with this parasite?

Could this perhaps work with a brain?

Comment author: Dorikka 05 November 2011 04:03:34PM *  5 points [-]

Even after reading the Wikipedia article, I'm having trouble imagining how a small/medium mammal evolves into a tumor.

Comment author: AlexSchell 05 November 2011 04:57:45PM 34 points [-]

I think the trouble might come from imagining the process as a gradual process by which a dog population evolved into a tumor population (which is not what happened; the wording in the original post is pretty misleading). The dog-to-tumor part is actually the easier and less shocking part of the story. Tumors are basically just cells that by some mutation have trouble regulating cell division and then divide uncontrollably. Malignant tumors (what we call cancers) are just tumors that happen to harm the organism (and maybe metastasize). So this particular tumor was once a dog cell, just as every human cancer starts out as a human cell. The interesting part of the story is that the tumor got to have a limited ability to survive outside of the original dog's body, and got to be able to survive within other dogs and other canids.

Comment author: Tyrrell_McAllister 06 November 2011 06:58:35PM *  9 points [-]

The dog evolved into a tumor in the same sense in which Henrietta Lacks evolved into a cell line. If the cell lines descended from the original Lacks culture managed to spread into the wild, you would have essentially the same story. You might then say that Lacks evolved into a species of single-celled organisms.

Comment author: Konkvistador 06 November 2011 08:53:21PM *  12 points [-]

The genes that built her found a better vector to spread themselves.

Comment author: [deleted] 05 November 2011 04:03:42PM 8 points [-]

I don't know, but H.R. Giger needs to illustrate it.

Comment author: cousin_it 06 November 2011 04:37:48AM *  12 points [-]

This is creepily similar to the plot of Kurt Vonnegut's novel Galapagos, published in 1985 (Homo floresiensis was discovered in 2003). In the novel, all of humanity dies out due to an epidemic, except for a small band of humans who get stranded on the Galapagos islands (reference to Darwin's voyage). Over the following millennia these humans evolve into aquatic mammals with much smaller brains.

What's the critical population size for the effect to occur? Does it imply that SF "generation ships" are doomed? How about isolated arcologies?

Comment author: gwern 14 November 2011 07:53:45AM 8 points [-]

The canonical example is, I think, the aborigines of Tasmania after they were cut off from the mainland. Over the 8000 years of isolation, the ~10,000 Tasmanians lost most of their technology - fishing, the ability to make fire or bone tools, etc.

One would hope literacy would help a lot, but then again, a generation ship needs astoundingly more expertise than a hunter-gatherer tribal society.

Comment author: wedrifid 14 November 2011 08:16:16AM *  2 points [-]

The canonical example is, I think, the aborigines of Tasmania after they were cut off from the mainland. Over the 8000 years of isolation, the ~10,000 Tasmanians lost most of their technology - fishing, the ability to make fire or bone tools, etc.

The story, as I read when visiting relevant sites in Tasmania (and confirmed on wikipedia) is one of "necessity is the mother of invention" in reverse - Tasmania being a veritable paradise compared to most of the mainland. Fishing traps for scaled fish were not especially important given the effort they required compared to eating shellfish and seals while environmental changes and increasing tribal territory sizes made hunting land animals even easier. They also never lost fire.

This example isn't especially strong evidence that technology loss is caused by a 10k population size.

Comment author: gwern 14 November 2011 08:36:01AM 5 points [-]

And why didn't Malthusian limits encourage them to maintain their technology? (I also didn't say they lost fire, but the ability to make it.)

Comment author: sam0345 11 November 2012 09:40:54PM 2 points [-]

After 1830 or so there is a PC reluctance to mention certain facts about the Tasmanian aboriginals that people previous to that time found glaringly obvious.

Comment author: wedrifid 12 November 2012 12:34:02AM *  8 points [-]

After 1830 or so there is a PC reluctance to mention certain facts about the Tasmanian aboriginals that people previous to that time found glaringly obvious.

I was actually reading about Tasmanian aboriginals of that time last night. In particular I had been reminded that Melbourne was actually founded by Batman, which just seems kind of badass. Knowing that said Batman acquired some of the resources needed to found Melbourne (then "Batmania") by being rewarded for capturing a notorious bushranger made it seem even more badass. It was somewhat less rewarding to discover that Batman got most of his wealth and prominence from hunting down and massacring Tasmanian Aboriginals in the Black War, which was going on at the very time that you mention (1830).

The above leads me to devalue rather heavily that which was being said about the Tasmanian aboriginals at the time. People who are in the process of killing another group of people in order to take their land aren't the kind of people you go to for unbiased opinions about their victims.

Comment author: MugaSofer 13 November 2012 09:18:06AM 0 points [-]

What facts? That they were all bumbling idiots? That's just racism. You got that wherever European explorers went, and was demonstrably wrong in every case I've ever come across.

Comment author: RichardKennaway 06 November 2011 05:12:07PM *  0 points [-]

As I understand it, it's not that a small population directly causes intelligence loss, but that intelligence is less of a selective advantage in an isolated population with no big fierce predators, and the costs of growing a huge brain become unfavourable. Perhaps body size also comes into it: isolated populations on a small island are known to evolve towards smaller bodies, and smaller bodies generally go with smaller brains.

What is required of a successful generation ship to maintain and improve intelligence is to design it in such a way that intelligence remains a selective advantage. The simplest method in the context of speculative future technology would be controlled breeding, but that is not so easily applied to the generation ship that is this planet.

Comment author: jimrandomh 06 November 2011 05:24:40PM 10 points [-]

As I understand it, it's not that a small population directly causes intelligence loss, but that intelligence is less of a selective advantage in an isolated population

What is required of a successful generation ship to maintain and improve intelligence is to design it in such a way that intelligence remains a selective advantage. The simplest method in the context of speculative future technology would be controlled breeding, but that is not so easily applied to the generation ship that is this planet.

The article argues that small population does directly cause intelligence loss - or rather, that it breaks anything that depend on too many parts of the the genome to be too precisely balanced. But why would you let genetic drift and natural selection operate on a generation ship at all? That's a recipe for disaster; it's nearly impossible to predict what results would come out of it. It'd be much better to bring along frozen embryos (or something equivalent).

Comment author: beriukay 07 November 2011 08:03:45AM 5 points [-]

but how exactly does one internalize something like that?

There's a blog trying to do just that. Nature Wants To Eat You.

Comment author: Thomas 11 November 2011 08:53:51AM 3 points [-]

So ... after 20 k years or so, we have established that our skulls are shrinking and will probably continue to do so, until the gift of our intelligence will ceassed to be.

After - say 10 k years - we would be unable to spark a civilization, science and so on. It seems, ve bearly cought the train.

Comment author: JoshuaZ 11 November 2011 08:00:28PM 8 points [-]

It isn't clear if our skulls are becoming smaller means we are becoming stupider. It is possible that other changes were happening to our brains and the emphasis was on making brains faster and more efficient. Note also that if we have been in fact getting stupider, that could be due to civilization as it puts less pressure on needing high general intelligence.

Comment author: Izeinwinter 27 November 2014 12:10:48PM 0 points [-]

Pfffthfhhf. The most likely cause of the shrinkage, in terms of selective pressure, is that maternal mortality and starvation were big killers, and being smart didn't help much when it came to not dying from them. That's no longer the case. More importantly, natural selection for human beings is over. Seriously, the opinion of the blind god is no longer relevant because he is very slow and tech is very fast. Something else will remake our species profoundly long before genetic pressures have time to do anything whatsoever. AI, Genetech, uploading, cyborging... If human beings continue to exist at all, as opposed to just getting a game-over ? Evolution just isn't going to get a say. At all.

Comment author: JoshuaZ 27 November 2014 03:29:51PM 0 points [-]

The most likely cause of the shrinkage, in terms of selective pressure, is that maternal mortality and starvation were big killers, and being smart didn't help much when it came to not dying from them.

If this were the case, how would they have gotten large in the first place? What would have changed to make starvatio n and maternal mortality larger killers than they were earlier?

Comment author: Izeinwinter 27 November 2014 11:04:51PM 0 points [-]

"Agriculture" for the first. For the second, maternal mortality has always been the main limit on human cranial size, Giving birth is ridiculously dangerous to human beings compared with other mammals, and our infants are much less developed, both of which is directly linked to the fact that our heads are such outliers in size, and there is in addition a whole host of finicky adaptions to accommodate the largest head possible. - the infant soft spot in the skull, the extra wide pelvis.. There must have been really absurdly strong selection pressure for "bigger brains" for a long time to create all that, and it pushes the envelope on what is biologically practical for our bodyplan quite hard.

Comment author: Nisan 06 November 2011 05:52:28PM 1 point [-]

There was an illustrated book floating around in pdf form a few years ago, but now I can't find it. It describes the history of the next several billion years of history in our galaxy. In an act of revenge, the most powerful branch of Homo sapiens decides to bioengineer all other intelligent species, including all descendants of humans. The bulk of the book is a taxonomy of the results. Some lineages lose the capacity for self-awareness. Others are reduced to flat, square laminae without hands or locomotion, but retain their self-awareness, the better to appreciate their condition.

Comment author: Tyrrell_McAllister 06 November 2011 07:10:15PM 3 points [-]

Stephen Baxter's Evolution has (rot13) aba-fncvrag qrfpraqragf bs uhznaf jub unir orra qbzrfgvpngrq ol vagryyvtrag qrfpraqragf bs engf (VVEP).

Comment author: summerstay 07 November 2011 11:57:18AM *  2 points [-]

I'm guessing you mean Man After Man: An Anthropology of the Future by Dougal Dixon. More a horror book than a rational extrapolation of future human evolution. For a great early attempt at this kind of thing, take a look at Olaf Stapledon's Last and First Men, published in 1930.

Comment author: J_Taylor 08 November 2011 05:46:57PM *  1 point [-]

Man After Man is similar. However, there is another book which he or she may be referring to.

Comment author: Nisan 08 November 2011 06:42:44PM 2 points [-]

Yeah, I took a look at After Man and Man After Man, and neither is the book I was thinking of, although they are similar.

Comment author: J_Taylor 03 August 2013 05:55:25PM 2 points [-]
Comment author: Nisan 03 August 2013 08:01:31PM 4 points [-]

Yeah, that's it! Here's a pdf.

Comment author: more_wrong 02 June 2014 01:09:40PM 0 points [-]

Moreover, we know of examples where natural selection has caused drastic decreases in organismal complexity – for example, canine venereal sarcoma, which today is an infectious cancer, but was once a dog.

Or human selection. Henrietta Lax (or her cancer) is now many tonnes of cultured cells; she has become an organism that reproduces by mitosis and thrives in the niche environment of medical research labs.