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The Psychological Diversity of Mankind

76 Post author: Kaj_Sotala 09 May 2010 05:53AM

The dominant belief on this site seems to be in the "psychological unity of mankind". In other words, all of humanity shares the same underlying psychological machinery. Furthermore, that machinery has not had the time to significantly change in the 50,000 or so years that have passed after we started moving out of our ancestral environment.

In The 10,000 Year Explosion, Gregory Cochran and Henry Harpending dispute part of this claim. While they freely admit that we have probably not had enough time to develop new complex adaptations, they emphasize the speed at which minor adaptations can spread throughout populations and have powerful effects. Their basic thesis is that the notion of a psychological unity is most likely false. Different human populations are likely for biological reasons to have slightly different minds, shaped by selection pressures in the specific regions the populations happened to live in. They build support for their claim by:

  • Discussing known cases where selection has led to rapid physiological and psychological changes among animals
  • Discussing known cases where selection has led to physiological changes among humans in the last few thousand years, as well as presenting some less certain hypotheses of this.
  • Postulating selection pressures that would have led to some cognitive abilities to be favored among humans.

In what follows, I will present their case by briefly summarizing the contents of the book. Do note that I've picked the points that I found the most interesting, leaving a lot out.

They first chapter begins by discussing a number of interesting examples:

  • Dogs were domesticated from wolves around 15,000 years ago: by now, there exists a huge variety of different dog breeds. Dogs are good at reading human voice and gestures, while wolves can't understand us at all. Male wolves pair-bond with females and put a lot of effort into helping raise their pups, but male dogs generally do not. Most of the dog breeds we know today are no more than a couple of centuries old. There is considerable psychological variance between dog breeds: in 1982-2006, there were 1,110 dog attacks in the US that were attributable to pit bull terriers, but only one attributable to Border collies. Border collies, on average, learn a new command after 5 repetitions and respond correctly 95 percent of the time, while a basset hound needs 80-100 repetitions for a 25 percent accuracy rate.
  • A Russian scientist needed only forty years to successfully breed a domesticated fox. His foxes were friendly and enjoyed human contact, very unlike wild foxes. Their coat color also lightened, their skulls became rounder, and some of them were born with floppy ears.
  • While 50,000 years may not be enough for new complex adaptations to develop, it is enough time for them to disappear. A useless but costly adaptation will vanish in a quick period: fish in lightless caves lose their sight over a few thousand years at most.
  • An often-repeated claim is that there's much more within-group human genetic variation than between-group (85 and 15 percent, to be exact). While this is true, the frequently drawn conclusion, that phenotype differences between individuals would be larger than the average difference between groups, does not follow. Most (70 percent) of dog genetic variation is also within-breed. One important point is that the direction of the genetic differences tends to be correlated: a particular Great Dane may have a low-growth version of a certain gene while a particular Chihuahua has a high-growth version, but on the whole the Great Dane will still have more high-growth versions. Also, not all mutations have the same impact: some have practically no effect, while others have a huge one. Since the common ancestry of humans (or dogs) is so short, observable differences between populations must have evolved rapidly, which is only possible if the mutations had a strong selective advantage.
  • There are gene variants causing observable differences in appearance between human populations, such as the ones causing light skin color or blue eyes. For such systematic differences to appear, there must have been big effects on fitness, anything up from a 2 or 3 percent increase. From the rate at which new alleles have spread, this must be the case at least for genes that determine skin color, eye color, lactose tolerance, and dry earwax.
  • Molecular genetics has found hundreds of cases of mutations that indicate recent selection. Many of them are very recent. A significant number of Europeans and Chinese bear mutations that originated at about 5,500 years ago. The rate at which new mutations have been popping up and spreading over the past few thousand years is on the order of 100 times greater than the long-term rate over the past few million years.

The second chapter of the book is devoted to a discussion about the "big bang" in cultural evolution that occured about 30,000 to 40,000 years ago. During that time, people began coming up with technological and social innovations at an unprecedented rate. Cave paintings, sculpture and jewelry starting showing up. Tools made during this period were manufactured using materials hundreds of miles away, when previously they had been manufactured with local materials - implying that some sort of trade or exchange developed. Humans are claimed to have been maybe 100 times as inventive than in earlier times.

The authors argue that this was caused by a biological change: that genetic changes allowed for a cultural development in 40,000 BC that hadn't been possible in 100,000 BC. More specifically, they suggest that this could have been caused by interbreeding between "modern" humans and Neanderthals. Even though Neanderthals are viewed as cognitively less developed than modern humans, archeological evidence suggests that at least up to 100,000 years ago, they weren't seriously behind the modern humans of the time. Neanderthals also had a different way of life, being high-risk, highly cooperative hunters while the anatomically modern humans probably had a mixed diet and were more like modern hunter-gatherers. It is known that ongoing natural selection in two populations can allow for simultaenous exploration of divergent development paths. It would have been entirely possible that the anatomically modern humans interbred with Neanderthals to some degree, the Neanderthals being a source of additional genetic variance that the modern humans could have benefited from.

How would this have happened? In effect, the modern humans would have had their own highly beneficial alleles, in addition to which they'd have picked up the best alleles the Neanderthals had. Out of some 20,000 Neanderthal genes, it's highly likely that at least some of them were worth having. There wasn't much interbreeding, so Neanderthal genes with a neutral or negative effect would have disappeared from the modern human population pretty quickly. On the other hand, a beneficial gene's chance of spreading in the population is two times its fitness advantage. If beneficial genes are every now and then injected to the modern human population, chances are that eventually they will end up spreading to fixation. And indeed, both skeletal and genetic evidence shows signs of Neanderthal genes. There are at least two genes, one regulating brain size that appeared about 37,000 years ago and one playing role in speech that appeared about 42,000 years ago, that could plausibly have contributed to the cultural explosion and which may have come from the Neanderthals.

The third chapter discusses the effect of agriculture, which first appeared 10,000 or so years ago. 60,000 years ago, there were something like a quarter of a million modern humans. 3,000 years ago, thanks to the higher food yields allowed by agriculture, there were 60 million humans. A larger population means there's more genetic variance: mutations that had previously occurred every 10,000 years or so were now showing up every 400 years. The changed living conditions also began to select for different genes. A "gene sweep" is a process where beneficial alleles increase in frequency, "sweeping through" the population until everyone has them. Hundreds of these are still ongoing today. For European and Chinese samples, the sweeps' rate of origination peaked at about 5,000 years ago and at 8,500 years ago for one African sample. While the full functions of these alleles are still not known, it is known that most involve changes in metabolism and digestion, defenses against infectious disease, reproduction, DNA repair, or in the central nervous system.

The development of agriculture led, among other things, to a different mix of foods, frequently less healthy than the one enjoyed by hunter-gatherers. For instance, vitamin D was poorly available in the new diet. However, it is also created by ultraviolet radiation from the sun interacting with our skin. After the development of agriculture, several new mutations showed up that led to people in the areas more distant from the equator having lighter skins. There is also evidence of genes that reduce the negative effects associated with e.g. carbohydrates and alcohol. Today, people descending from populations that haven't farmed as long, like Australian Aborigines and many Amerindians, have a distinctive track record of health problems when exposed to Western diets. DNA retrieved from skeletons indicates that 7,000 to 8,000 years ago, no-one in central and northern Europe had the gene for lactose tolerance. 3,000 years, about 25 percent of people in central Europe had it. Today, about 80 percent of the central and northern European population carries the gene.

The fourth chapter continues to discuss mutations that have spread during the last 10,000 or so years. People in certain areas have more mutations giving them a resistance to malaria than people in others. The human skeleton has become more lightly built, more so in some populations. Skull volume has decreased apparently in all populations: in Europeans it is down 10 percent from the hight point about 20,000 years ago. For some reason, Europeans also have a lot of variety in eye and hair color, whereas most of the rest of the world has dark eyes and dark hair, implying some Europe-specific selective pressure that happened to also affect those.

As for cognitive changes: there are new versions of neurotransmitter receptors and transporters. Several of the alleles have effects on serotonin. There are new, mostly regional, versions of genes that affect brain development: axon growth, synapse formation, formation of the layers of the cerebral cortex, and overall brain growth. Evidence from genes affecting both brain development and muscular strength, as well as our knowledge of the fact that humans in 100,000 BC had stronger muscles than we do have today, suggests that we may have traded off muscle strength for higher intelligence. There are also new versions of genes affecting the inner ear, implying that our hearing may still be adapting to the development of language - or that specific human populations might even be adapting to characteristics of their local languages or language families.

Ruling elites have been known to have far more offspring than those of the lower classes, implying selective pressures may also have been work there. 8 percent of Ireland's male population carries an Y chromosome descending from Niall of the Nine Hostages, a high king of Ireland around AD 400. 16 million men in central Asia are direct descendants of Genghis Khan. Most interestingly, people descended from farmers and the lower classes may be less aggressive and more submissive than others. People in agricultural societies, frequently encountering lots of people, are likely to suffer a lot more from being overly aggressive than people in hunter-gatherer societies. Rulers have also always been quick to eliminate those breaking laws or otherwise opposing the current rule, selecting for submissiveness.

The fifth chapter discusses various ways (trade, warfare, etc.) by which different genes have spread through the human population throughout time. The sixth chapter discusses various historical encounters between humans of different groups. Amerindians were decimated by the diseases Europeans brought with them, but the Europeans were not likewise decimated by American diseases. Many Amerindians have a very low diversity of genes regulating their immune system, while even small populations of Old Worlders have highly diverse versions of these genes. On the other hand, Europeans had for a long time difficulty penetrating into Africa, where the local inhabitants had highly evolved genetic resistances to the local diseases. Also, Indo-European languages might have spread so widely in part because an ancestor protolanguge was spoken by lactose tolerant herders. The ability to keep cattle for their milk and not just their flesh allowed the herders to support larger amounts of population per acre, therefore displacing people without lactose tolerance.

The seventh chapter discusses Ashkenazi Jews, whose average IQ is around 112-115 and who are vastly overrepresented among successful scientists, among other things. However, no single statement of Jews being unusually intelligent is found anywhere in preserved classical literature. In contrast, everyone thought that classical Greeks were unusually clever. The rise in Ashkenazi intelligence seems to be a combination of interbreeding and a history of being primarily in cognitively challenging occupations. The majority of Ashkenazi jews were moneylenders by 1100, and the pattern continued for several centuries. Other Jewish populations, like the ones the living in the Islamic countries, were engaged in a variety of occupations and do not seem to have an above-average intelligence.

Comments (153)

Comment author: JenniferRM 10 May 2010 08:26:49PM *  14 points [-]

(EDITED TO ADD: Do not reply to this comment. There is now a top level post for Q&A with the authors of the book which is a better place for you to post your questions than here. The text below is being left "as is" for historical purposes.)

Henry Harpending, one of the authors of the book being reviewed, has already posted a comment here. In order to maximize the value of his attention, I requested and received his permission by email to post this.

The goal is to have a relatively clean "Q&A" grow out of this comment, with interesting child questions posted by members of the community and grandchild answers posted by Henry Harpending or Gregory Cochran which a reader can easily peruse.

If you have any questions for either Harpending or Cochran, please reply to this comment with a question addressed to one or both of them. Material for questions might be derived from their blog for the book which includes stories about hunting animals in Africa with an eye towards evolutionary implications (which rose to my attention based on Steve Sailor's prior attention).

Please do not kibitz in this Q&A... instead go to the kibitzing area to talk about the Q&A session itself. Eventually, this comment will be edited to note that the process is been closed at which time there should be no new questions.

Comment author: RichardKennaway 10 May 2010 10:18:07AM 14 points [-]

People in agricultural societies, frequently encountering lots of people, are likely to suffer a lot more from being overly aggressive than people in hunter-gatherer societies. Rulers have also always been quick to eliminate those breaking laws or otherwise opposing the current rule, selecting for submissiveness.

On the other hand, submissiveness is surely selected against in rulers, who as noted in the posting leave more descendants than proles. So perhaps in a society in which the strong rule and the weak submit there is some evolutionarily stable distribution along a submissive/aggressive spectrum, rather than favouring one or the other?

Comment author: harpend 09 May 2010 04:01:10PM 35 points [-]

Very nice summary--thanks.

@SilasBarta:re our careers:

I would certainly never encourage a graduate student to follow up in this area because it would be a career kiss of death. But I am at retirement age, no one is going to fire me, and most important of all I do not have federal grant support. Cochran is not an academic: his real career is in laser physics. So we enjoy a kind of freedom that few academics do.

@JanetK re skin color:

According to standard ag-sci 101 theory the number of loci makes no difference at all to the speed of change of a multi-locus trait. Six is close enough to infinity that skin color should change no faster than, say, IQ. OTOH you may be right in the real world because of the complexities of epistasis of loci.

Comment author: thomblake 10 May 2010 07:03:40PM 4 points [-]

Welcome to Less Wrong!

Note that there are threaded comments here - you can click 'reply' on the bottom of any comment.

Comment author: teageegeepea 09 May 2010 09:54:32PM 2 points [-]

Cochran was a laser physicist who came to dabble in the biology of infectious diseases with Paul Ewald. He is now an anthropologist at the University of Utah. Harpending is as well, and has been for some time.

Comment author: Jack 09 May 2010 10:41:36PM 13 points [-]

Harpending is as well, and has been for some time.

...pretty sure you're talking to him.

Comment author: teageegeepea 11 May 2010 01:53:11AM 4 points [-]

Doh! I should really not rush so much.

Comment author: ObliqueFault 09 May 2010 04:20:49PM 9 points [-]

I'm going to nitpick a couple points here.

"There is considerable psychological variance between dog breeds: in 1982-2006, there were 1,110 dog attacks in the US that were attributable to pit bull terriers, but only one attributable to Border collies"

Though pit bull terriers are indeed much more dangerous than collies, it may not be entirely behavioral genetics. Unlike collies, pits are often trained to be aggressive. Pits are also simply much stronger and more resistant to pain than than collies, so their attacks are more difficult to defend against, and thus more likely to cause injury, and thus more likely to be reported.

"A larger population means there's more genetic variance: mutations that had previously occurred every 10,000 years or so were now showing up every 400 years. "

True, but a larger population also means that "genetic sweeps" would take longer, especially given our relatively long life spans. If agricultural humans evolved more rapidly I'd say it was more likely due to new selection pressures that their hunter-gatherer ancestors didn't have.

Comment author: jimmy 09 May 2010 07:50:26PM 5 points [-]

It only takes longer by a logarithmic factor, so overall, new genes are picked up at a higher rate.

Comment author: Johnicholas 10 May 2010 08:19:47PM 5 points [-]

Another point about the (IMO, dubious) "pit bulls are more dangerous" claim.

It's possible that young/aggressive/defensive male humans more often purchase dog breeds that look aggressive (or have an aggressive reputation) and young/aggressive/defensive male humans more often mistreat their dogs, leaving them chained and untrained.

Similarly, dog breeds that look aggressive (or have an aggressive reputation) may elicit different, more dangerous, patterns of behavior (fear, fear-based-defensiveness, et cetera) than "Lassie dogs".

Comment author: PhilGoetz 10 May 2010 10:18:42PM 5 points [-]

But how did these dogs get the aggressive reputation in the first place?

Comment author: gwern 11 May 2010 03:02:17AM 7 points [-]

And really, a stereotype leads to a 1110:1 ratio? Mighty powerful things, those stereotypes.

Comment author: Sticky 15 May 2010 07:20:48PM 3 points [-]
Comment author: TobyBartels 08 October 2012 07:00:32PM 2 points [-]
Comment author: Johnicholas 12 May 2010 06:37:38PM *  1 point [-]

How did they get an aggressive reputation in the first place? Perhaps, by fighting other dogs publicly, with advertising for the fights focusing on their aggressiveness.

Comment author: timtyler 09 May 2010 08:16:05AM *  7 points [-]

I checked the Wiki here: http://wiki.lesswrong.com/wiki/Human_universal

"Let's say that you have a complex adaptation with six interdependent parts, and that each of the six genes is independently at ten percent frequency in the population. The chance of assembling a whole working adaptation is literally a million to one; and the average fitness of the genes is tiny, and they will not increase in frequency. "

Right - but look at the premise. Genes have linkage to other genes on the same chromosome - and so their frequencies may be far from independent. The existence of this possibility actually creates a selection pressure for interdependent genes that contribute to an adaptation to migrate towards each other on chromosomes - so they have more chance of being inherited together.

Comment author: Fly 11 May 2010 03:49:19AM 0 points [-]

Two other factors: 1) Population sub structure matters. Suppose a population of one million is divided into mating bands with 30 individuals. Small bands tend to lose diversity so some bands would have some of the minor alleles at higher frequency. Now suppose band X has minor alleles A1, A2, and A3 at high frequency while band Y has minor alleles A4, A5, and A6 at high frequency. The two bands meet and party. The result is kids with all 6 minor alleles. Those kids have big fitness advantage and those minor allele frequencies are significantly boosted in those bands. The high local concentration of those alleles means even more kids with all 6 alleles are born, further increasing their frequency. (If individuals were equally likely to mate with anyone in the population then local concentrations would be diluted in one generation and there would be no effective selection. But individuals are far more likely to mate with related nearby bands, so high local concentrations of the minor alleles are maintained while the minor alleles slowly become the major alleles.)

2) Gene variants tend to have additive affects. Also most genes affect multiple traits simultaneously. So the all or nothing scenario given above would be rare. More likely you would have a diversity of environmental niches. In some of those niches the minor alleles would provide benefit due to one of their affected traits becoming more important. The frequencies of that minor allele would locally rise (while its frequency in the total population would remain low). E.g., a minor allele might provide protection against a specific pathogen. So there might be local environments where the probability of 6 minor alleles combining could be much higher than would occur in one large population in a uniform environment mating randomly.

Comment author: JanetK 09 May 2010 10:35:22AM 16 points [-]

I see the differences between this post and the psychological unity of mankind one is akin to two ships passing in the night - not talking about the same thing. In general the arguments do not contradict each other.

I would like to make a few additions:

1) We cannot compare the speed of change in dogs (or pigeons) with that in wild populations. Mongrel and feral dogs are under selection in their normal environment and without control of their breeding therefore they resemble one another much, much more than do pure bred animals. The tame foxes if freed would return fairly quickly to being foxy. Humans on the other hand have continuously changed the environment in which they live (for say 50,000 years). Therefore the selective pressure is not static. So it is not surprising that new genes can arise and flow through populations. Dogs are not relevant here.

2) Genetics is more complex than algebra. In many cases there is an advantage to having two different alleles and both alleles in double dose are disadvantageous. Genes are duplicated (as a mutation) and then one allele can be conserved while another evolves under selective pressure. There are genes that control the use of groups of other genes and mutations in these can effect hundreds of genes. Epigenetic changes to genes can give very complex effects. Environmental control of genetic expression is important. Genetics is probably like an iceberg that we have not glimpsed the complexity of yet.

3) Eliezer was talking about the deep structure of our anatomy and physiology while the 10,000 year explosion book is about fairly surface differences. For example, skin colour is under the control of a small number of genes and responds relatively quickly to differences in environments sunlight (say 20-50,000 years to lighten or darken to ideal when a population moves). But human skin differs in more fundamental ways from that of other animals -amount of hair, sweat glands, amount of fat etc. Human skin is universal while its colour tracks the environment.

So in general there is nothing terribly wrong with either Eliezer's post or the present one - except nit picking complaints (The dog thing is maybe me nitpicking). They are not opposed unless you have a hangup about whether genetics is important or not.

Comment author: SilasBarta 09 May 2010 11:06:10AM *  8 points [-]

I don't understand. How are they not different? EY's post said that the time since leaving the ancestral environment is too short to allow significant divergence, including for psyche-related genes (except across genders). This book says that certain selective pressures do permit variation to happen much faster, and there is evidence that this effects the psyche. This contradicts the basis for EY's claiming that there can't have been much divergence.

Also, regarding your 1), humans can go feral if they they go into the wild before significant assimilation into their birth culture.

Comment author: Kutta 09 May 2010 01:17:37PM *  9 points [-]

This contradicts the basis for EY's claiming that there can't have been much divergence.

I think all this talk is rather non-rigorous as of now. How much exactly is "much" divergence and how great part of the disagreements here is semantic ambiguity and smuggled-in meanings and how great part is different beliefs on matters of fact? I for one agree with JanetK that basically both the OP and Eliezer's notion of psychological unity hold water. SilasBarta, you think that OP contradicts psychic unity, so you have to mean a different thing by unity than what I mean.

When I think about psychic unity I visualize a cosmopolitan scale that includes rocks, lizards and humans. The perceived degree of cross-cultural and individual differences should be weighed together by our being adapted to notice very fine differences between humans, I think (and that implies that one's assessment of divergence and unity is definitely not binary but is on a continuum).

Also, as it has been said many times, current science on human genetic variance is muddled and politically charged. This situation will hopefully be improved with mass gene sequencing, but I think that as of now many of our beliefs (mine for sure) rely greatly on personal impressions and musings, especially when it's about variance's implications on moral philosophy.

Comment author: Konkvistador 12 November 2011 10:53:58AM *  0 points [-]

The tame foxes if freed would return fairly quickly to being foxy. Humans on the other hand have continuously changed the environment in which they live (for say 50,000 years). Therefore the selective pressure is not static. So it is not surprising that new genes can arise and flow through populations. Dogs are not relevant here.

Arguably while conditions have changed for humans massively in the recent past the same could be said of many domesticated animals or at least dogs (as a fun exercise check out how often the primary used and role of dogs has changed in say Anatolia over recorded history).

And more importantly all this time we humans have basically been self-domesticating ourselves.

So dogs are relevant.

Comment author: JenniferRM 10 May 2010 08:31:19PM *  5 points [-]

This is a parent for comments about Q&A with the authors of "The 10,000 Year Explosion".

If you have a question for either Harpending or Cochran, please post the question as a response there. If you'd like to talk about the Q&A, this is the place to do it.

Comment author: JenniferRM 10 May 2010 08:51:04PM *  4 points [-]

It occurred to me while I was arranging "infrastructure comments" for Q&A with Harpending and Cochran that my unilateral action to set this up might be seen by the community as inappropriate or poorly executed for various reasons.

If you'd like to express displeasure with my efforts please downvote this comment and send me a PM by clicking on my name and then hitting the "Send message" button. If I receive private messages by this method I will attempt to summarize their contents and post the lessons learned in this same kibitzing area.

Hopefully, before criticizing, you will first ask a question of the authors, and then provide feedback on the process by which this was set up :-)

Comment author: Blueberry 12 May 2010 06:38:29PM 0 points [-]

Upvoted to express pleasure for your efforts, which were appropriate and well executed. :)

Comment author: mattnewport 11 May 2010 12:37:18AM 1 point [-]

Moved this here from the Q&A thread.

Simple traits (such as an organism's height) are probably relatively easy to alter via genetic mutations, without needing to combine many different genes chosen from huge populations. So, e.g., dog breeding altered dogs’ size relatively easily.

Complex adaptations aren’t nearly so easy to come by.

I don't think your example supports your claim. It certainly appears that much more complex adaptations have been successfully bred into dogs. Kaj gave the examples of pit bulls and border collies. I grew up with border collies as pets and it is quite easy to observe their selected herding behaviour compared to other breeds - they want to herd everything, complex behaviour that is not typically observed in other breeds.

Casual observation strongly suggests much more complex adaptations than size in differing dog breeds and this appears to be supported by statistics like those Kaj cites. The superior sense of smell and tracking ability of bloodhounds is another example that springs to mind.

Comment author: AnnaSalamon 11 May 2010 01:33:46AM 3 points [-]

Your example of collie herding behavior is cool; I'm not sure what to make of that. Do wolves herd their pups? Or are there other plausible precedents? How complicated is collie "herding" behavior?

As to smell and tracking ability in blood hounds: given that these same abilities occur in wolves (though to a lesser extent?), my guess would be that these adaptations are relatively simple to acquire, if you have a wolf's genome as your starting point. Designing smell for the first time would be complicated, but designing a better sense of smell from a wolf's sense of smell might just require sending more brain cells to the "process smells" brain center, or building more of the kinds of olfactory receptors dogs already have, or some other simple shift. (OTOH, if blood hounds are sensitive to many compounds that wolves aren't sensitive to, or if they exhibit many strategies in tracking that wolves don't exhibit, I'd be wrong and surprised. Let me know if that's so.)

Comment author: Kaj_Sotala 11 May 2010 01:37:54AM 4 points [-]

IIRC, herding is explicitly mentioned in the book as a behavior that wolves do and which has been strengthened by selection in some dog races.

Comment author: harpend 11 May 2010 03:51:24AM 4 points [-]

Right, wolves pack-hunt which involves pretty complex management of prey herds including something like a "theory of prey mind" to predict what the prey will do.

There is a lot known about cape dog hunting because they are in fairly open country and can be observed. Not only do they predict where the prey herd will go, they coordinate and signal to each other with postures during the chase. It is absolutely beautiful to watch, like stop-action ballet.

HCH

Comment author: mattnewport 11 May 2010 01:55:29AM *  2 points [-]

How complicated is collie "herding" behavior?

It can get quite complicated. That video has some post-production trickery but supposedly the majority of the herding is real. Sheep herding is sufficiently complicated that there was an English TV show devoted to it for many years called One Man and His Dog. I believe border collies dominate sheepdog trials but there are other herding breeds.

Comment author: MugaSofer 21 January 2013 11:03:05PM 0 points [-]

I think he was referring to instinctive herding behaiviors, not trained ones.

Comment author: MugaSofer 21 January 2013 11:05:45PM 0 points [-]

As to smell and tracking ability in blood hounds: given that these same abilities occur in wolves (though to a lesser extent?), my guess would be that these adaptations are relatively simple to acquire, if you have a wolf's genome as your starting point. Designing smell for the first time would be complicated, but designing a better sense of smell from a wolf's sense of smell might just require sending more brain cells to the "process smells" brain center, or building more of the kinds of olfactory receptors dogs already have, or some other simple shift.

It's worth noting that size and shape differences are unusually easy to get from wolves, something to do with unusually flexible genes for skeletal morphology in the womb IIRC.

Comment deleted 09 May 2010 02:30:43PM [-]
Comment author: Nanani 11 May 2010 02:39:01AM 1 point [-]

Well put!

We might want to come up with another name for (2). Humans are closer to each other in mindspace than they are to any alien mind, but it does not follow that, close up, all humans have the exact same psychology.

There may be more than zoom-degree involved in the difference.

Comment deleted 09 May 2010 02:35:09PM [-]
Comment author: Jack 11 May 2010 12:27:12AM 5 points [-]

After thinking about this I'm not sure AS entails an attraction to consequentialist morality so much as it does an attraction to consistent, axiom-based and systematized theories plus a willingness to ignore (or a lack of) situational and emotional reactions that contradict their systematized view. Consequentialism is just the obvious consistent and systematized view suggested by contemporary post-Enlightenment Western culture. I mean, unless the autism spectrum was empty prior to Bentham it seems likely people with AS were engaged in convoluted theological arguments and Natural law ethics during the middle ages. It is plausible Kant himself had AS. The only difference is that he was ignoring the intuition that it is okay to lie to compliment grandma's poor cooking and to keep a murder from killing your friend where is today, people are ignoring the intuition that it isn't okay to push the guy onto the track to stop a trolley or carve up the homeless guy for his organs.

I'd predict you'd see over-representation of AS among the followers of other contemporary philosophies that are highly consistent and axiom-based but also at odds with majority intuitions: For example, libertarian rights-based morality and Objectivism.

Comment author: SilasBarta 10 May 2010 02:05:53AM *  7 points [-]

Yes, and I often see stark examples of how this difference in psychology reveals itself. It typically involves a NT joking about the observed behavior of an AS, where the "funny" bit takes the form, "[AS person] performed [action X], when you're OBVIOUSLY supposed to do ~X, though I am completely incapable of saying how ~X inexorably follows as the right one based on typical social experience."

Real example (some details may be off) that's representative of what I see a lot: "Yeah, there's this real weird kid in this class I teach who had read about the Protestant Reformation, but get this -- he actually pronounced it 'pro-TEST-ant'! It was SO funny [because obviously English has a really rigorous orthography that's designed to prevent this kind of thing]!"

I would like to see Eliezer Yudkowsky address the issues raised by NT/AS and by this book, because his position does have a lot of tension with it, even if there's no direct contradiction. (I'm guessing he can dismiss the NT/AS issues a being relatively small in the grand scheme of things.)

Comment author: NancyLebovitz 10 May 2010 11:59:54AM *  10 points [-]

It was SO funny [because obviously English has a really rigorous orthography that's designed to prevent this kind of thing]!"

I'm pretty sure that's not how that sort of neurotypical is thinking. It's more like "of course everyone is always alert to get the social details right, and it's shocking incompetence to fall down on the job!".

If so, we're back to psychological unity of the human race-- geeks sneering at people who can't manage to understand completely obvious things about computers are showing the same lack of imagination.

Comment author: SilasBarta 10 May 2010 07:15:23PM 3 points [-]

I'm pretty sure that's not how that sort of neurotypical is thinking. It's more like "of course everyone is always alert to get the social details right, and it's shocking incompetence to fall down on the job!".

My point was that such instances reveal psychological diversity, and the characterization of such a mistake as incompetence is the proof of diversity, so I don't see how that contradicts my point. With psychological unity, people might still see it as funny (maybe because pro-TEST-ant is a weird sound), but not on the basis of it revealing incompetence.

If so, we're back to psychological unity of the human race-- geeks sneering at people who can't manage to understand completely obvious things about computers are showing the same lack of imagination.

If you're saying that geeks laugh at how non-geeks fail to make the correct inference about computers from the same experience, that looks like more evidence of psychological diversity.

Comment author: NancyLebovitz 10 May 2010 07:22:34PM 7 points [-]

My point was that it's common for people to think of their own skills as normal, and to think it's ridiculous when other people don't have those skills.

The skills may be different, but the assumption that everyone should have at least moderate skill at what comes easy to you is the same.

Comment author: SilasBarta 10 May 2010 07:46:05PM *  -1 points [-]

The skills may be different, but the assumption that everyone should have at least moderate skill at what comes easy to you is the same.

And the belief that "Y, rather than Z is the obvious inference given X " is different across people, and is evidence of psychological diversity, and is the case frequently, including here. The universal presence of a belief of the form "You should have moderate skill at X" does not contradict this.

Comment author: JohannesDahlstrom 16 May 2010 11:13:10PM *  2 points [-]

If Oceanians consider Eur...Eastasians, their mortal enemies, unworthy of human dignity, and Eastasians regard Oceanians, their hated antagonists, as little more than maggots to be crushed, then that is not an example of psychological diversity; instead, it's two different instances of underlying psychological unity - in this case, of the universal "Us vs. Them" heuristic.

Comment author: SilasBarta 17 May 2010 12:20:57AM *  0 points [-]

But this doesn't map to an "us vs. them" heuristic; it maps to an "X implies Y vs. X implies ~Y". The fact that the differing beliefs about what X implies leads to a universal dislike of the "other" does not deny the neurodiversity in the former heuristic.

Comment author: alecrene 17 May 2010 10:50:55AM *  1 point [-]

Yes but the term "psychological unity" is about hardware. Neurodiversity in terms of magazine selection does not necessarily have a genetic link even though it will show that we are neurodiverse. Difference in magazine selection can lead to a difference in what one believes X implies.

Comment author: MugaSofer 21 January 2013 11:19:08PM -1 points [-]

People are not necessarily born with their current skill set, though, yes?

Comment author: MugaSofer 21 January 2013 11:17:24PM 0 points [-]

geeks sneering at people who can't manage to understand completely obvious things about computers are showing the same lack of imagination.

Upvoted for pointing this out.

Comment author: RobinHanson 10 May 2010 09:36:51PM 7 points [-]

Perhaps someone could outline the perceived tension in more detail? We already knew humans weren't identical. So just how much variation is how much of a problem for what?

Comment author: PhilGoetz 10 May 2010 10:21:58PM 3 points [-]

Wait, what? Can you give some references on Aspergers => different axiology (new word for me)? And how does Aspergers => consequentialist morality, and how does not compartmentalizing + consequentialism => singulatarianism?

It sounds interesting, but there are 3 unsupported and dubious-sounding links in that chain.

Comment deleted 10 May 2010 10:56:14PM [-]
Comment author: PhilGoetz 11 May 2010 10:28:02PM *  1 point [-]

I have often seen that people who support more consequentialist inferences display lower social skills and abilities.

The "theory theory of mind" says that autistics lack the ability to simulate someone else's reasoning. If this is true, and Asperger's is like autism, people with it might be likely to judge people on the basis of consequences, since they have no model of other peoples' intentions.

Although, now that I think about it, if someone has no cognitive model, but just observes a large set of instances of

<situation, action, outcome>

and finds a way to classify them as "good(action)" or "bad(action)"; and if situation + action usually determines outcome; is there any difference between being a consequentialist (making a lookup table of outcome -> action), or a deontologist (making a lookup table of situation -> action)?

I still don't understand the connection between Asperger's and compartmentalizing.

if you are an altruistic consequentialist, and you search heard for the most important charitable cause, you'll find that Singularitarianism is it.

How does that argument rely on you being a consequentialist? Other ethical systems have to do with, eg., measuring intended consequences instead of actual consequences, not ignoring consequences.

Comment deleted 11 May 2010 10:37:13PM *  [-]
Comment author: PhilGoetz 11 May 2010 11:17:44PM 1 point [-]

The biggest dividing-line that I've observed between value systems is between people who believe that a decision was right if it produced good consequences; and people who believe that a decision was right if, given the information available when the decision was made, it was expected to have good consequences.

If both are consequentialism, then what terminology do you use to distinguish them?

Comment author: steven0461 10 May 2010 09:24:25PM 2 points [-]

Yet tons of non-AS people are consequentialists, so maybe AS people just happen to have a head start in reaching a conclusion that informed people eventually reach anyway.

Comment author: thomblake 10 May 2010 09:53:02PM 3 points [-]

Yet most AS people that are studied are fairly young, so maybe it's fully explainable by the hypothesis that consequentialism is an ethical position held by immature people.

Comment author: BenAlbahari 09 May 2010 02:57:33PM *  3 points [-]

Voted up because I think AS is a great example of psychological diversity. I'm curious however as to the origin of your belief that AS people are more attracted to decompartmentalization than neurotypicals are.

Comment deleted 09 May 2010 04:24:00PM *  [-]
Comment author: ata 09 May 2010 04:55:04PM *  8 points [-]

I've picked up some anecdotal evidence for that over the past few months. Just a week ago I was talking with one guy with AS about some ethics problems; he brought up an example where you're with 20 other people, including a baby who won't stop crying, hiding from an approaching army. Under some simplified assumptions, if the baby keeps crying, the army will find and kill all of you, and if the baby stops, they probably won't. If killing the baby is the only way to stop it, is it moral to do so? The consequentialist answer seemed obvious to both of us, even when he specified that the army would spare the baby's life but kill the rest of you. He told me that this is a characteristically autistic way of thinking about moral problems, and he's had more contact with autistic/AS people than I have (aside from being one himself), so I'm inclined to believe him. (I'm not AS myself, but I'm apparently close enough that several people at several points in my life have suspected it, but not enough to be diagnosed with it.)

Edit: He wasn't sure about torture vs. dust specks, but that seemed to be more because he didn't see how a problem involving such impossibly huge numbers of people could have any useful implications about more realistic ethical scenarios. I disagreed — the math is the same, and I think pathological cases are useful for testing the integrity and consistency of ethical theories and for testing how seriously a person takes the theory/methodology they profess to follow — but he didn't find that particular point to be relevant.

Comment deleted 09 May 2010 10:42:29PM [-]
Comment author: Vladimir_M 09 May 2010 11:03:55PM *  11 points [-]

Are you sure "flummoxed" is the right word? I don't think "neurotypicals" are confused by the mathematics involved. They just dispute that the utilitarian math represents an accurate theory of ethics. Would you use the word "flummoxed" for a physicist who understands the mathematics of a theory but disputes that it says anything relevant about the real world, even if he has no alternative theory to offer?

For full disclosure, I am not convinced by utilitarian arguments at all, both in these problems you mention and in most other widely disputed ones. I understand them with perfect clarity; I just dispute that they have any relevance beyond the entertainment value of the logical exercise, and possibly propaganda value for some parties in some situations. I certainly wouldn't describe my situation as "flummoxed."

Comment deleted 10 May 2010 01:05:08AM *  [-]
Comment author: SilasBarta 10 May 2010 02:14:38AM *  10 points [-]

Many neurotypicals I have spoken to will take really extreme positions on the fat man trolley problem, saying that they wouldn't push the fat man off the bridge even if a million people were on the trolley.

Eh, as I've argued before on LW, there are utilitarian, AS-compatible justifications for such a position: specifically, that your heroic act shuffles around the risk profiles of various activities in unpredictable ways, thus limiting the ability of people to manage risks, leading them to waste significant resources (perhaps exceeding the amount that would otherwise save more than a million lives) returning to their preferred risk profile.

The key part:

By intervening to push someone onto the track, you suddenly and unpredictably shift around the causal structure associated with danger in the world, on top of saving a few lives. Now, people have to worry about more heros drafting sacrificial lambs "like that one guy did a few months ago" and have to go to greater lengths to get the same level of risk.

In other words, all the "prediction difficulty" costs associated with randomly changing the "rules of the game" apply. Just as it's costly to make people keep updating their knowledge of what's okay and what isn't, it's costly to make people update their knowledge of what's risky and what isn't (and to less efficient regimes, no less).

Note that this doesn't argue for a deontological prohibition, but rather, argues about the consequences of sudden deviations from social norms, without assumption of their categorical justness.

ETA: In terms of Timeless Decision Theory, you could put it this way: if people knew that bridge-walkers are drafted for deadly work on a moment's notice, it's much less likely you'd have a fat person handy to begin with. So, the way TDT calculates probabilities, the EU of pushing the fat guy off is very small on account of its low TDT-probability, eliminating the supposed utility gain.

Comment author: NancyLebovitz 10 May 2010 08:05:49PM 7 points [-]

It' isn't just about being fat while being on a bridge over trolley tracks, of course. It might be a worse world if people generally believed they should take deadly action when they see a utilitarian win.

Comment author: CarlShulman 10 May 2010 06:27:34PM 3 points [-]

Much less likely? That would require that such drafting be more likely on bridges than elesewhere (how often do these train accidents happen?) Also, ex ante one is more likely to find oneself one of the million saved than the one person sacrificing, so most everyone should agree to a policy that those in positions to offer incredible help be drafted.

Comment author: SilasBarta 10 May 2010 07:10:13PM 3 points [-]

Much less likely? That would require that such drafting be more likely on bridges than elesewhere

The problem induced by pushing the fat guy off is that people don't know which zones now count as "sacrificial lamb" zones (because of the bizarreness of the deviation from social norms), except that bridges over densely-populated trolley tracks are one of them, so I think the resulting world meets this criterion.

one is more likely to find oneself one of the million saved than the one person sacrificing, so most everyone should agree to a policy that those in positions to offer incredible help be drafted.

But people are already choosing risk profiles that, under present social norms, cause them to die when near tracks that have an errant trolley coming, so it's not clear why they'd make tradeoffs (giving up other things they value) for greater near-trolley safety, and thus not clear why they'd prefer this at all.

In this case, the cost (borne by everyone in the area, not just people near tracks) is that they have to re-organize their lives around choosing routes that avoid sacrificial lamb zones. But -- by the scenario's stipulation -- people aren't currently choosing to bear the additional cost to be on the safer bridge rather than the dangerous track. (If they were, the scenario would involve millions crossing the bridge and few near the track.) What they are choosing is to bear the risk of death because of the convenience it affords.

And because the option of pushing someone off the track tells people, "Okay, you have to be a lot more risk averse to get your current level of risk", they're forced to pay more for the same safety.

Comment author: Vladimir_M 10 May 2010 02:21:42AM *  14 points [-]

On the other hand, don't forget that talk is cheap, and actions speak louder than words. I doubt that many utilitarians would be willing to follow their conclusions in practice in situations such as the fat man/trolley problem. To stress that point even further, imagine if you had to cut the fat man's throat instead of just pushing him (and feel free to increase the cost of the alternative if you think this changes the equation significantly relative to pushing). I'd bet dollars to donuts that a large majority of the contemporary genteel utilitarians couldn't bring themselves to do it, no matter how clear the calculus that -- according to them -- mandates this course of action.

This suggests to me that this "dumbfoundedness" might be in fact a consequence of more clear and far-reaching insight, not confusion. Biting moral bullets is easy in armchair discussions; what you'd actually be able to bring yourself to do is another question altogether. Therefore, when I see people who coolly affirm the logical conclusions of their favored formal ethical theories even when they run afoul of common folks' intuition, I have to ask if they are really guided by logic to an exceptional degree in their lives -- or do they simply fail to see, out of sheer mental short-sightedness, how remote their armchair theorizing is from what they'd be willing and capable to do if they, God forbid, actually found themselves in some such situation.

(This is not the reason why I don't see any validity in utilitarianism; that would be a topic for another discussion altogether. The point here is that logical consistency in ethical armchair discussions could in fact be a consequence of myopia, not logical clear-sightedness.)

Comment deleted 10 May 2010 02:34:45AM [-]
Comment author: Vladimir_M 10 May 2010 02:54:52AM *  4 points [-]

You're allowed to say "X is the action I would want to take, but I wouldn't be able to"

I don't think this statement is logically consistent. Unless you're restrained by some outside force, if you don't do something, that means you didn't want to do it. You might hypothesize that you would have wanted it within some counterfactual scenario, but given the actual circumstances, you didn't want it.

The only way out of this is if we dispense with the concept of humans as individual agents altogether, and analyze various modules, circuits, and states in each single human brain as distinct entities that might be struggling against each other. This might make sense, but it breaks down the models of pretty much all standard ethical theories, utilitarian and otherwise, which invariably treat humans as unified individuals.

But regardless of that, do you accept the possibility that at least in some cases, bullet-biting on moral questions might be the consequence of a failure of imagination, not exceptional logical insight?

Comment author: Kaj_Sotala 10 May 2010 02:32:33AM *  9 points [-]

Interesting. This implies that there are actually two ways of interpreting such moral dilemmas: either as A) "what would you actually do in this situation", or B) "what would be the right thing to do in this situation, regardless of whether you'd actually be capable of doing it".

I've always interpreted the questions as being of type B, but the way you write suggests you're thinking of them as being type A. I wonder how much of the disagreement relating to these questions is caused by differing interpretations.

Comment author: Vladimir_M 10 May 2010 03:33:15AM *  16 points [-]

It's more complicated than that. Most people would say that there are imaginable situations where a certain course of action is right, but they'd be strongly tempted to act differently out of base motives. For example, if you ask a typical person whether it would be right to gain a large amount of money by some sort of cheating, assuming you know for sure there won't be any negative consequences, they'll immediately understand that the question is about what's normatively right, not how they'd be tempted to act. Some very sincere people would probably admit that they might yield to the temptation, even though they consider it wrong.

Now, imagine you're introduced to someone who had the opportunity to cheat a business partner for a million dollars with zero risk of repercussions, but flat-out refused to do so out of sheer moral fiber. You'll immediately perceive this person as trustworthy and desirable to deal with -- a man who acts according to high principles, not base passion and instinct. In contrast, you'd shun and despise him if you heard he'd acted otherwise.

However, let's now compare that with the extreme fat man problem (where you'd have to cut the fat man's throat to avert some greater loss of life). Imagine you're introduced to someone who was faced with it and who slit the fat man's throat without blinking. Would you feel warm and fuzzy about this person? Would any of the bullet-biting utilitarians fail to be profoundly creeped out just by the knowledge that they are standing next to someone who actually acted like that -- even though they'd all defend (nay, prescribe!) his course of action relentlessly when philosophizing? Moreover, I would again bet dollars to donuts that our genteel utilitarians would be much less creeped out by someone who couldn't bring himself to butcher the fat man.

When I think about this, I honestly can't but detect severe short-sightedness in moral bullet-biters.

Comment author: NancyLebovitz 10 May 2010 12:03:31PM 6 points [-]

I can believe that a neurotypical person would be more likely to imagine themselves doing the actual killing, while someone on the AS would be more likely to stay with the abstract problem.

Comment author: Jack 10 May 2010 01:33:02AM 4 points [-]

I was going to dispute your use of "flummoxed" as well but then I realized my position on normative ethics is basically an extended defense of moral dumbfoundedness and decided that I wouldn't be the best person to make that argument.

I think anyone who is biting bullets and defending rational principles broadly applied is just more comfortable dropping intuitions (or holds them less strongly) and less comfortable with logical inconsistency (sound like anyone you know?). But I don't think that makes their claims about morality any truer than the dumbfounded. I disagree that the right answer to inconsistent intuitions is just deciding to pick some intuitions and ignore them.

Comment deleted 10 May 2010 02:01:51AM [-]
Comment author: Jack 10 May 2010 02:16:36AM *  3 points [-]

You can keep all of them if you're okay saying that sometimes there are only immoral choices (or at least no moral ones) and that sometimes the action we ought to take is under-determined by our moral intuitions.

Comment author: Jack 09 May 2010 10:54:35PM *  3 points [-]

I wonder if the higher rate of consequentialists here relative to the general population or the population of ethicists might be explained solely by differing rates of AS plus self-selecting consequentialists here because they have found kindred hearts.

Have we ever polled for demographics on neurotypicality?

Comment deleted 10 May 2010 12:59:35AM *  [-]
Comment author: neq1 10 May 2010 03:27:58PM 3 points [-]

This is an interesting thread. Admittedly, I've often thought to myself when reading LW posts: "this post was clearly written by someone with AS". If people with AS are drawn to sites like this, maybe that, in part, explains why there seems to be many more men here than women. I wonder if the male:female LW ratio is similar to the male:female AS ratio in the general population.

Comment author: Alicorn 10 May 2010 04:15:04PM *  3 points [-]

Autism in general affects four times as many men than women in the general population; but I've noticed that a surprisingly high proportion of the autistic "public figures" - given that ratio - are women. Temple Grandin, for instance, may be the most famous person with autism around; and a majority of the autism bloggers I've run across are female. I don't know why this is.

Comment author: Vladimir_M 10 May 2010 07:09:31PM *  7 points [-]

Autism in general affects four times as many men than women in the general population;

Does this statistic refer only to severe cases of autism that are likely to be noticed and diagnosed whenever they occur, or also to the milder, high-functioning autism spectrum disorders? Because if the latter, I would expect that mildly autistic men are much more likely to be noticed as weird and dysfunctional than women, so this might account for at least a part of the discrepancy in the rate of diagnosis.

The explanation for the greater public prominence (and presumably social acumen) of female autistics is probably similar. In most situations, it's probably harder for autistic men than women to avoid coming off as creepy or ridiculous.

Comment author: MC_Escherichia 10 May 2010 04:24:43PM 1 point [-]

Are the words "women" and "men" reversed in your opening sentence?

Comment author: Nanani 11 May 2010 02:36:14AM 0 points [-]

Does "autism bloggers" mean "people who blog specifically about autism"?

If so, it might be instructive to check how many bloggers in other subjects also happen to have autism. It might be dificult to verify but the blogosphere is large enough to dig up a usefully-sized sample and disentangle to some degree the autism-blogging link.

Comment author: steven0461 10 May 2010 09:25:20PM 2 points [-]

e.g. think that destruction of the world is OK, but be horrified by the death of a particular person

This seems like exactly the sort of attitude that would disappear in any reasonable preference extrapolation algorithm.

Comment author: SilasBarta 10 May 2010 03:00:02PM 1 point [-]

I don't have evidence for that proposition, but I wanted to (shamelessly) point out that attraction to decompartmentalization can be phrased as a willingness to go from Level 1 to Level 2 in my hierarchy. That is, to go from understanding domains independently, to checking for global consistency and multi-directional implication across them.

Comment author: SilasBarta 09 May 2010 08:37:18AM 7 points [-]

Sounds neat! Thanks for going to the effort to summarize it!

However, now I'm worried. Your summary indicates that Cochran and Harpending are saying a lot of stuff that suggests a genetic basis for intelligence. How long until their careers are over?

Comment author: gaffa 09 May 2010 04:42:50PM 5 points [-]

If we're looking to find out if humans vary significantly in their psychological phenotypes, why not compare these phenotypes directly rather than appealing to highly shaky evolutionary speculations about genotypes?

(Sure, environmental variation also contributes to phenotypic variation, but we have no reason to believe that the current level of human psychological variation is masked by environmental factors - especially since right now environmental variation is probably at its peak in human history)

Comment author: PhilGoetz 10 May 2010 10:16:16PM *  10 points [-]

I'm sure the NIH would love to fund research comparing cognitive phenotypes of different races! Just remember to budget for nails and a cross in your proposal.

From Science, March 12 2010, p. 1316:

'Elsevier told Charlton [editor of a controversial Elsevier non-peer-reviewed journal that published AIDS denial articles] on 22 January that Medical Hypothesis would have to become a peer-reviewed journal. Potentially controversial papers should receive careful scrutiny, the publisher said, and some topics - including "hypotheses that could be interpreted as supporting racism" - should be off-limits.'

Comment author: MugaSofer 21 January 2013 11:12:49PM -1 points [-]

Did I see the word "race" in the comment you're replying to? No I did not.

To be clear, you made an excellent point, I just think it could be worked around by simply not basing it on race - by location, say, or grandparents location, or surveying a bunch of pheotypes - some physical, some psychological - and identifying clusters (could seems either racist or anti-racist depending on wording.)

Comment author: PhilGoetz 10 May 2010 10:28:45PM *  2 points [-]

Great post!

The rise in Ashkenazi intelligence seems to be a combination of interbreeding and a history of being primarily in cognitively challenging occupations.

Or of having very high selection for being able to predict when your neighbors are going to try to kill you again. Or of being the only major group of people not having high selection pressure for skill at war for the past 2000 years, letting traits that give other advantages spread more rapidly.

(I don't think interbreeding can raise a population's intelligence. It can just keep it from dissipating.)

Comment author: NihilCredo 17 May 2010 04:18:48PM 2 points [-]

I think it can, e.g. if it takes an unusual open-mindedness for a local to marry into a despised and/or feared subgroup.

Comment author: xamdam 09 May 2010 06:44:00PM 2 points [-]

Superb review - the book has been lingering on my stack for a while, now I feel I've read 1/2 of it.

Comment author: JoelSammallahti 09 May 2010 07:36:09AM *  2 points [-]

Damn, looks like an interesting book! Is it entertainingly written? (Looking for a belated mother's day gift.)

Comment author: Kaj_Sotala 09 May 2010 09:07:52AM 3 points [-]

I'd say that, yeah - some of the subheadings are pop culture references, and there are occasional jokes scattered among the text. Like, when discussing the origin of the protolanguage that Indo-European languages descended from:

It's fair to say that the problem of the location of the Indo-European homeland, called "the Urheimat" (German for "original homeland"), has been a subject of controversy - indeed, the question has had a tendency to drive men mad. Various fruitcakes have suggested Tibet, North Africa, the shores of the Pacific, and the North Pole. There's a distinct tendency for scholars to place the wellspring of the European peoples somewhere in their own backyard. So far, thank God, we haven't seen any American linguists try that.

Comment author: timtyler 09 May 2010 07:53:45AM *  4 points [-]

It seems to be a fairly trivial observation that all adult men and all women do not share the same underlying psychological machinery - because machinery malfunctions - during development, because of bad genes, and as a result of trama and other pathology - so there are quite a few people who are broken and have missing pieces.

There are, of course, also sex and age differences - if you consider all humans.

I argued against the premise of the "The Psychological Unity of Humankind" essay long ago here: http://alife.co.uk/essays/species_unity/

Comment author: Kaj_Sotala 09 May 2010 09:13:08AM 3 points [-]

Indeed. The "psychic unity of mankind" is probably true to some degree on the level of different cultures, but far less so on the level of individuals. (I mean, we even have people who've had half their brain removed and are seemingly of normal intelligence, and that's not even going to the weird neuroscience cases.)

Comment author: timtyler 09 May 2010 01:04:26PM 2 points [-]

"More specifically, they suggest that this could have been caused by interbreeding between "modern" humans and Neanderthals."

Probably bunk, IMO. An entertaining story, but lacking supporting evidence.

Comment author: ObliqueFault 09 May 2010 04:28:11PM 6 points [-]

Actually, there is genetic evidence now.

http://www.sciencedaily.com/releases/2010/05/100506141549.htm

There are genes lacked by Africans that are shared by Neanderthals and non-Africans. Interbreeding seems the most likely explanation for this pattern.

Comment author: timtyler 09 May 2010 07:04:12PM 3 points [-]

I wasn't doubtful about interbreeding - that is all over the news. I was doubtful about interbreeding being the cause of the cultural explosion. Like I said, no evidence. In fact, contrary evidence, since Neanderthals were largely a European phenomenon.

Comment author: ObliqueFault 09 May 2010 07:35:03PM 4 points [-]

Neanderthals were also in the Near East.

http://en.wikipedia.org/wiki/List_of_Neanderthal_sites

You have a point about the cultural explosion, though. Africans don't seem to be less cultural than non-Africans, despite the fact that they don't seem to have any links to Neanderthals. It occurs to me that this lack of a link, after all this time, exemplifies how slow gene sweep is in a population as numerous, long-lived, and spread out as humanity.

Comment author: gaffa 09 May 2010 04:55:44PM 2 points [-]

Where on Earth have you been for the last couple of days? : ] Hiding in a Croatian cave?

That being said, we currently have no reason to believe that this interbreeding had any phenotypic effects on the human lineage.

Comment author: timtyler 09 May 2010 07:07:22PM 4 points [-]

I am not aware of any evidence that "the "big bang" in cultural evolution that occured about 30,000 to 40,000 years ago" was caused by interbreeding with Neanderthals. That is probably bunk, IMHO. An entertaining story, but lacking in supporting evidence.

Comment author: knb 09 May 2010 11:14:23PM *  1 point [-]

Great post. However I would contend that psychological unity of mankind seems more like a minority belief on LW.

Comment author: PhilGoetz 10 May 2010 10:01:25PM 3 points [-]

Eliezer's writings about FAI and CEV, and most discussion about them here, assume that the psychological unity of mankind is great enough that you can build one FAI that tries to optimize human experience WRT one value system, and this will be (in some sense that I don't understand) the "right thing to do".

Comment author: CarlShulman 10 May 2010 10:15:28PM *  3 points [-]

FAI that tries to optimize human experience

For idealized human preference.

Comment author: PhilGoetz 10 May 2010 10:35:06PM 2 points [-]

I don't see how that makes a difference WRT the required degree of psychological unity. Just talking about "idealized human preference" assumes either psychological unity, or moral realism.

Comment author: DuncanS 10 May 2010 09:32:29PM *  1 point [-]

This is a really interesting subject with so many possible theses.

To state the obvious, we are all intellectually very different. And I don't think the difference between now and 40,000 years ago has to be all that significant. The less intelligent half of the population is fully human, obviously, but if everybody were at that level of intelligence, we would quite clearly still be making simple stone tools and living in caves. The difference between now and 40,000 years ago is therefore less than the natural variation in the population we see today. So I don't think the question of the psychological unity of mankind is really answered by considering selection over the last 40,000 or so years.

This isn't to say there might not be some quite significant changes in the population - even over historic time. If significant changes can happen in the way we digest milk in the time between now and the Romans, it's possible that average psychology has changed too. Our psychological environment has certainly been different over that period from our stone age forbears. Are we less aggressive? Brighter? On average, I mean.

One more thought. The average sweeping change in our genome, the author says, is about 5500 years old. This figure is almost certainly wrong, as it has a visibility bias. Mutations from that long ago have had time to become numerous, and so we have discovered them. But there must be many more such changes that one would have expected to have arisen in the far more numerous modern populations. These mutations probably exist in only tens, hundreds or thousands of people at the moment, and have therefore not been discovered. But if they have a selective advantage, they will grow. Assuming population genetics as usual, in 5500 years, there will be perhaps 10, 20, 50 times as many genes obviously sweeping the population as are obvious today.

Comment author: steven0461 10 May 2010 09:04:47PM *  1 point [-]

We already knew individuals vary in intelligence and personality, so those examples don't seem to me to provide any new evidence against psychological unity in the sense we've mostly been using it. Does the book give other examples of human psychological differences that might have arisen in the recent past?

Comment author: Jack 09 May 2010 08:22:13PM 1 point [-]

It would have been entirely possible that the anatomically modern humans interbred with Neanderthals to some degree, the Neanderthals being a source of additional genetic variance that the modern humans could have benefited from.

Can someone square this hypothesis with my understanding that Africa is the mos genetically diverse place on Earth. It seems like an culture explosion has to have at least as much to do with selection pressure as genetic diversity or else the beneficial genes present in the various African clusters would have spread.

Comment author: PhilGoetz 10 May 2010 10:12:52PM 2 points [-]

Non-Africans did interbreed with Neanderthals, as someone posted a few days ago. The recent article on the subject concluded that only Africans lack the Neanderthal genes.

Most genes present in Africa didn't have a chance to spread outside of Africa, because the people carrying the genes didn't spread outside of Africa. (There's a bit of chicken-and-egg to that answer.) The Sahara is a major barrier today. I don't know if it existed 20,000 years ago.

I don't know if it's known whether the diversity of genes in Africa developed historically, or recently. It's possible that the abundance of human parasites and diseases in Africa causes faster adaptation in response to them. The longer species X has been present in an area, or the higher the density of species X there, the better other species there are adapted to species X, the harder life is for species X, the faster species X evolves.

Comment author: thomblake 10 May 2010 10:17:58PM 2 points [-]

According to Wikipedia, the Sahara is about as dry now as it was 13,000 years ago, and has been around in some form or another for millions.

Comment author: Thomas 09 May 2010 08:03:53AM *  0 points [-]

Speaking about "big bang" here, one could extend this parallel to a lesser known fact, that our human genetic diversity is increased every day, every hour. Our "genetic universe" appears to be expanding at an increasing rate. Possibly the cultural also, despite the globalization and global culture, everybody talks about.

What could also be another major point of this interesting book, you have found somewhere in the bookspace.

Comment author: rpavellas 11 May 2010 04:28:51AM -1 points [-]

I'm not a scientist, so I'm looking at the subjects here from a different angle. I've read the Harpending/Cochran book and I've read the book "Born on a Blue Day" by Daniel Tammet, on his Asperger's Syndrome. I wrote an article offering the notion that perhaps we are all somewhere on the autism disorder spectrum: http://pavellas.wordpress.com/2008/05/21/where-are-you-on-the-autism-disorder-spectrum/ Best wishes, Ron Pavellas http://pavellas.com.

Comment author: Sniffnoy 11 May 2010 05:13:13AM *  9 points [-]

I'm not sure that statement is really meaningful in a nontrivial way. If we just consider autism, then there's some opposite end of that spectrum; of course everyone's somewhere on it, but you would expect most people to be at 0, or as near as makes no difference.

This seems a good time to point out that actually, there's now pretty good evidence that that spectrum does not end at neurotypicality, but continues past it to an actual "opposite" of autism - schizophrenia. Assuming this is correct, everyone is indeed somewhere on that spectrum!

Comment deleted 23 March 2011 10:43:05AM [-]
Comment author: RichardKennaway 23 March 2011 10:57:59AM -1 points [-]

I request that anupriya28 be excluded from this web site. He/she/it is touting web sites by making fake postings all over the Internet. I guess this is the next thing in spam after bots: fake postings written by people in sweatshops somewhere in the Third World.

What are they paying you, anupriya28? Is pissing in everyone else's soup the only way you can feed yourself?

Comment author: Vladimir_Nesov 23 March 2011 11:08:35AM 1 point [-]

Thanks, but it's sufficient to click the "report" link. (Also more reliable, since I can't read all comments on LW, and could miss the one you've made, but I do read all reported comments now.)

Comment author: RichardKennaway 23 March 2011 11:15:38AM 0 points [-]

I reported all of his comments, but I thought it worth giving public notice as well.

Comment author: Vladimir_Nesov 23 March 2011 11:21:48AM 1 point [-]

Maybe, though the way you phrased it doesn't sound optimal (as if you expected to convince the spammer, who is probably not a human), and there was little point in substantiating the claim that this is spam, an out-of-context external link to a trash commercial resource in spammer's comment was sufficient evidence.