What's the consensus on the rapid evolution of humans?

[bascule]

My own hypothesis has always been that the rapid evolution of humans came about through tribal warfare in which one tribe would wipe out all the (male) members of the other tribe, thus the best thinkers who were able to outsmart their enemy and the best communicators who were best able to work together against their enemy were favored by evolution, as those who lost out died. Thus we are descended from the best thinkers and speakers among the proto-humans. Is this how it happened?

 

Beyond that, I'd say socialization and forms of expression became intermingled with sex, and thus appreciation of music, dance, etc was genetically favored because it became a sex-linked behavior.

 

Am I at all on here with what SCIENCE has to say about it?

[Mayflower]

We weren't killing each other that often, were we?

[arkain101]

There is dozens of civilizations around the world that claim to be created in the same time era (10,000 year window). As far as I know these civilizations dont have much history or knowledge about life prior to their creation or beginning. They had gods.

 

Then you look at the proof of cave men style people that have left traces of evidence of there existance but there seems to be this large gap along the way where nothing leads up to the expansion of there populatoin around the world. It is like there was cave man.. then different cave men.. then a bit of a blank in recorded history then suddenly a bit of a wide spread upcoming of different style civilizations. I believe in evolution but I have been unable to fill this void in time where cave men style people evolved into social groups that understood construction and math and agricultrial knowledge. Its like you find caveman skulls and ancient human skulls but where are the half way in time skulls?

[j_p]

My own hypothesis has always been that the rapid evolution of humans came about through tribal warfare in which one tribe would wipe out all the (male) members of the other tribe' date=' thus the best thinkers who were able to outsmart their enemy and the best communicators who were best able to work together against their enemy were favored by evolution, as those who lost out died. Thus we are descended from the best thinkers and speakers among the proto-humans. Is this how it happened?

 

Beyond that, I'd say socialization and forms of expression became intermingled with sex, and thus appreciation of music, dance, etc was genetically favored because it became a sex-linked behavior.

 

Am I at all on here with what SCIENCE has to say about it?[/quote']

 

Well, you are leaving out half the human race, and the half with the better measurable communication skills at that. [This half is also the one that can be certain of passing on its genetic material, by the way].

 

And a brief glance at history indicates that assimilation has always been more successful a means of conquest that annihilation.

 

So, one could readily argue that the advancement of the species was brought about the female-gatherer [to accept a common assumption] sneaking off to the lower forty and figuring out how to seduce some cute lone male who was smart enough to escape anihilation in the battle.

 

And art and sex are different expression of the same impulse; art as an expression of the sublimation of the sexual impulse began and, thankfully, died with Joyce and Lawrence.

[lucaspa]

My own hypothesis has always been that the rapid evolution of humans came about through tribal warfare in which one tribe would wipe out all the (male) members of the other tribe' date=' thus the best thinkers who were able to outsmart their enemy and the best communicators who were best able to work together against their enemy were favored by evolution, as those who lost out died. Thus we are descended from the best thinkers and speakers among the proto-humans. Is this how it happened?

 

Beyond that, I'd say socialization and forms of expression became intermingled with sex, and thus appreciation of music, dance, etc was genetically favored because it became a sex-linked behavior.

 

Am I at all on here with what SCIENCE has to say about it?[/quote']

Have you done a PubMed search on this?

 

The consensus is that our intelligence and communication skills came about by cooperation and social interaction within the social group, not competition between social groups. If we look at stone age cultures today, they do not engage in warfare as a rule. So why would our ancestors have been different?

 

Remember, for most of our history, humans had primitive weapons and they were just as often prey as predator. Brains and communication were needed for cooperative behavior to both fend off predators and to cooperatively hunt large prey. For instance, the European cave bear makes the grizzly look like cuddly teddy bear. Yet when H. sapiens migrated into Europe, the cave bear went suddenly extinct. Both species wanted the same real estate -- caves -- but humans had better cooperation.

 

Since humans had to live in social groups to survive by cooperation, there was also the possibility of cheating by individuals within the group. So here too intelligence was needed both to 1) figure out new ways of cheating and 2) detect cheaters. A brain module to detect cheating is one of the few modules that evolutionary psychologists have really good data for.

[lucaspa]

Its like you find caveman skulls and ancient human skulls but where are the half way in time skulls?

??? The "cave men" skulls in Europe are Cro Magnon, who are us -- H. sapiens.

 

Now, if you mean going back to H. erectus (who was only sometimes a cave dweller) yes, there are skulls that are in between:

Erectus to sapiens: Omo valley. Omo-2 "remarkable mixture of Homo erectus and Homo sapiens characteristics" pg. 70.

Omo-1: another mix of erectus and sapiens

Omo Valley, Ethiopia: ~ 500,000 ya. mixture erectus and sapiens features

Sale in Morrocco: skull discovered in 1971, ~300,000 ya. also shows erectus and sapiens features.

Broken Hill skull: another skull with mixtures of erectus and sapiens features

 

Tautavel, 200Kya: large brow ridges and small cranium but rest of face looks like H. sapiens.

"We shall see the problem of drawing up a dividing line between Homo erectus and Homo sapiens is not easy." pg 65.

Ngaloba Beds of Laetoli, 120 Kya: ~1200 cc and suite of archaic (erectus) features.

Guamde in Turkana Basin, 180 Kya: more modern features than Ngaloba but in-between erectus and sapiens.

Skhul, Israel "posed a puzzle to paleoanthropologists, appearing to be almost but not quite modern humans"

Skhul and Jebel Qafza caves: "robust" H. sapiens at 120 Kya that have brow ridges like erectus but brain case like sapiens.

Bouri http://news.nationalgeographic.com/news/2003/06/0611_030611_earliesthuman.html

http://www.berkeley.edu/news/media/releases/2003/06/11_bones-background.shtml

actual paper: http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v423/n6941/full/nature01669_r.html

Vertesszollos, 400 Kya. Teeth like H. erectus but occipital bone like H. sapiens. brain ~ 1300 cc

 

As to civilization, we can see intermediates all over the planet today. Tribes that have agriculture and some building but not massive amounts of technology. The Masai and Zulus in the 19th century come immediately to mind.

 

The "Ice Man" discovered in the Alps dating to 15000 years ago shows intermediate civilization. It appears he was on a trading trip south of the Alps (commerce) but died on the return trip. Trading implies an economy where goods and services are traded, which in turn implies a civilization.

[bascule]

The consensus is that our intelligence and communication skills came about by cooperation and social interaction within the social group[/b'], not competition between social groups.

 

You are incorrectly interpreting my statements. That is exactly the point I was trying to make.

 

With tribal warfare, in-group communication is key to survival. From my original post:

 

...thus the best thinkers who were able to outsmart their enemy and the best communicators who were best able to work together against their enemy were favored by evolution[/b'], as those who lost out died.

 

Speech related traits became genetically fixed at an uncharacteristically fast rate. And from an evolutionary perspective this can be for one of two reasons:

 

Superior speech was a trait that was needed for reproduction (i.e. sex linked)

Superior speech was a trait that was needed for survival

 

So, I merely stated my hypothesis for the latter... tribal warfare. I was wondering what evidence there was for either of the above explanations...

 

Were the poor communicators shunned or otherwise sexually unattractive, and if so, wouldn't they simply reproduce among themselves?

 

My conjecture is that in order for speech to become genetically fixed as fast as it did, the poor communicators had to somehow be wiped out by the superior communicators. I think tribal warfare certainly fits that conjecture well. But since I have no evidence of this for my own, I'm basically looking for anything which would support or refute this...

[Ophiolite]

Speech related traits became genetically fixed at an uncharacteristically fast rate. .

Based on what evidence please? Uncharacteristically fast for what? A creature with a wholly unique brain that was in the process of developing culture. Why would you expect a 'characteristic rate' of 'genetic fixation'?

Superior speech was a trait that was needed for reproduction (i.e. sex linked)

Superior speech was a trait that was needed for survival

Superior speech was favoured through improved survival and reproduction. It was not needed by it. To phrase it in this way is to rewrite the principles of evolution.

 

You seem to be making an unwarranted leap into groundless, and unnecessary speculation. Lucaspa's summary of current thinking on this matter presents a much more cogent and cohesive explanation in my view.

[bascule]

Based on what evidence please? Uncharacteristically fast for what? A creature with a wholly unique brain that was in the process of developing culture. Why would you expect a 'characteristic rate' of 'genetic fixation'?

 

I'll get back to you on that once I can find something... little busy at the moment

 

Superior speech was favoured through improved survival and reproduction. It was not needed by it. To phrase it in this way is to rewrite the principles of evolution.

 

From my understanding the fixation of speech occured virtually overnight on evolutionary timescales. You're trying to describe the general principle and overlooking that I'm talking about a case instance (did you bother reading the thread topic?). In this case instance, my conjecture is that the rapidity was brought about by the necessity of the trait.

 

I could be wrong! I'll try to substantiate my claims.

 

You seem to be making an unwarranted leap into groundless, and unnecessary speculation. Lucaspa's summary of current thinking on this matter presents a much more cogent and cohesive explanation in my view.

 

It also agrees with exactly what I'm saying, but I'm trying to draw attention to what I understand to be a rather short timescale which lucaspa's sources and analysis omitted completely. Again, it could be because I'm wrong.

 

And honestly, is what I'm saying here that hard to comprehend? I feel like I have to keep reexplaining myself because people are misunderstanding me...

[j_p]

I'll try to substantiate my claims.

That would help.

 

And honestly' date=' is what I'm saying here that hard to comprehend? I feel like I have to keep reexplaining myself because people are misunderstanding me...[/quote']

I don't think that people are mis-understanding you; I think they are disagreeing with some premises.

 

My own hypothesis has always been that the rapid evolution of humans came about through tribal warfare ...

Lucaspa disagrees that warfare was the prime cause.

 

...in which one tribe would wipe out all the (male) members of the other tribe, ...

I pointed out that the other tribe's genetic material would not be wiped out.

 

...thus the best thinkers who were able to outsmart their enemy and ...

I pointed out that, if one is to accept your warfare-as-the-prime-cause premise, running and hiding would be an even more sucessful means of retaining the opportunity to pass on one's genetic material.

 

...the best communicators who were best able to work together against their enemy...

Lucaspa [and I] pointed out other advantages to good communication skills than making battle-plans; it just occurs to me that communicating during an attack does not particularly favor speech as a means of communication.

 

...were favored by evolution, as those who lost out died....

I'm going to go out a limb here, and propose that a lot of people on this board get really annoyed by gross simplifications of theories of evolutionary mechanisms.

 

... Thus we are descended from the best thinkers and speakers among the proto-humans. Is this how it happened?

Now that's a premise I would love to read an informed debate on.

 

Beyond that, I'd say socialization and forms of expression became intermingled with sex, and thus appreciation of music, dance, etc was genetically favored because it became a sex-linked behavior.

So, all the accomplishments of culture over entire history of humans and proto-humans except war is dismissed as other stuff, as sex.

 

You know, there are other human impulses than war and sex.

 

Take communication; why are we all on this board?

Sex? Charmed as I am by some posters, intelligible explanations of plate tectonics do not move me to irrestible passion.

To indulge aggressive impulses? Well ... only when I have had a really bad day at work...

To carve out virtual territory? Well, there are a few people who might have that impulse.

We are all here to just hang out, talk, and pick up a bit of interesting information; to refine our intellectual reality with debate and information.

 

I was going to gone on to discuss other human impulses, but I have convinced myself that the desire to communicate is the defining characteristic of humans, and not a result of mechanistic evolution.

 

War? A perversion of the desire to communicate, to force one's world view on another.

 

Sex? Hell, yes. There is no better form of communication that physical contact.

[JonM]

What about the ice age? I’ve heard that it wiped out most humans and the 1000 or so that survived went on to produce all of us? They had to be the smartest and most fit to survive that time.

 

 

Also the development of speech (and then later on language) sent our intelligence flying. Same thing with out ability to tame fire, or to use tools etc...

 

 

But I suppose if you look at it from a whole, its accelerating. Our development has been exponential and still is.

[lucaspa]

You are incorrectly interpreting my statements. That is exactly the point I was trying to make.

 

With tribal warfare, in-group communication is key to survival.

 

But your premise involves competition between the communication skills of one tribe vs the communication skills of another tribe. You have competition between tribes. I am saying that the competition was not with tribes, but with predators and prey and members of your own tribe: the cheaters. As far as I can see, the evidence is against frequent intertribal warfare. The same negotiating skills that allowed intratribal coopertation would work toward intertribal negotiations to avoid conflict.

 

Speech related traits became genetically fixed at an uncharacteristically fast rate. And from an evolutionary perspective this can be for one of two reasons:

 

Superior speech was a trait that was needed for reproduction (i.e. sex linked)

Superior speech was a trait that was needed for survival

What is your data for "uncharacteristically fast rate"? We get humans in social groups from at least 4 million years ago. Since you are talking 50,000 years ago, that is 3.95 million years for speech related traits to become genetically fixed.

 

Even the FOXP2 allele that allows more complex speech is 100,000 years old.

Molecular evolution of FOXP2, a gene involved in speech and language. Wolfgang Enard, Molly Przeworski, Simon E. Fisher, Cecilia S. L. Lai, Victor Wiebe, Takashi Kitano, Anthony P. Monaco, Svante Pääbo Nature 418, 869 - 872 (22 Aug 2002)

 

My conjecture is that in order for speech to become genetically fixed as fast as it did,

This seems to be your premise. Only it seems unjustified by the data.

 

I think tribal warfare certainly fits that conjecture well. But since I have no evidence of this for my own, I'm basically looking for anything which would support or refute this...

1. Modern tribes at that level of technology don't engage in frequent warfare. Why do you think tribes then did?

2. Of all the human and hominid fossils found, only a few neandertal fossils bear evidence of trauma due to human weapons. If tribal warfare were as common as you hypothesize, we should find that a large percentage of such fossils would bear testimony to old wounds.

[lucaspa]

What about the ice age? I’ve heard that it wiped out most humans and the 1000 or so that survived went on to produce all of us? They had to be the smartest and most fit to survive that time.

Where did you hear this? Neandertals lived near the ice.

 

Now, genetic data does show that about 200,000 years ago H. sapiens went thru a genetic bottleneck. Thus we are all descended from a small breeding pool. But I have never seen it connected to any of the ice ages.

9. A Gibbons, Studying humans -- and their cousins and parasites. Science 292:627-629, April 27, 2001.

 

Also the development of speech (and then later on language) sent our intelligence flying. Same thing with out ability to tame fire, or to use tools etc...

The use of tools sent our technology flying. That is different from intelligence, altho most people confuse technology with intelligence.

 

 

But I suppose if you look at it from a whole, its accelerating. Our development has been exponential and still is.

Again, our technological development is exponential. But that is NOT intelligence. Technology, in evolutionary terms, is a very small adaptation: the ability to make tools to make tools. An incremental step from chimps and other species that can make tools. But a step that has enormous results.

[arkain101]

I was refering the space where there was monkey shaped skulls H.sapiens then there was later on less monkey shaped h.sapiens. But there is this gap where tribes of H.sapiens learned how to build pyramids and make potery and make cloths.. I havnt studied it much but where does history have proof that the H.sapiens started building colonies on a mass scale. I just cant see cavemen (i am refering to sapiens living in caves) learning to speak difficult languages and build buildings and cities over a span of 100liftimes out of the blue. The gap between livingin tribes in caves to becoming city like colonies.

somewhere in the time there was an explosion in knowledge around all different kids of large grouped civilizations..

But the secluded tribal types were left as cavemen style people, who still exisit today. but these large groups became extensivly intelligent in a short period of time and write of visitors and teachers and gods and all this higher knowledge.. where did this come from.. I detect an influence.

[lucaspa]

I was refering the space where there was monkey shaped skulls H.sapiens then there was later on less monkey shaped h.sapiens. But there is this gap where tribes of H.sapiens learned how to build pyramids and make potery and make cloths.. I havnt studied it much but where does history have proof that the H.sapiens started building colonies on a mass scale. I just cant see cavemen (i am refering to sapiens living in caves) learning to speak difficult languages and build buildings and cities over a span of 100liftimes out of the blue. The gap between livingin tribes in caves to becoming city like colonies.

It is in recorded history that humans began living in large cities. So the proof is available.

 

But the secluded tribal types were left as cavemen style people, who still exisit today. but these large groups became extensivly intelligent in a short period of time and write of visitors and teachers and gods and all this higher knowledge.. where did this come from.. I detect an influence.

Notice that humans still living in hunter-gatherer tribes speak "difficult languages", by which I mean complex languages. So I don't see your problem in the paragraph above where you don't think "cavemen" could have difficult languages. Primitive technology does not = a lack of intelligence. Nor does technology = intelligence.

 

There are several articles and books discussing the rise of civiliations where stable agriculture became possible. The slash-and-burn style of agriculture does not lend itself to large civilizations because of the need to move frequently. In the Nile, Tigris-Euphrates, and Indus Valleys it was possible to farm the same fields year after year. Because of the need to calculate when the annual floods would happen, astronomy became necessary in the Nile Valley. The excess food meant more people since peoples did not starve or die of diseases made worse by malnutrition. With the increased food came the need to keep track of the food and the labor. Also, some people were not needed in producing food. These people were free to explore mathematics and technology.

 

Again, technology is NOT intelligence. Technology is cumulative. Also, the knowledge needed in a city is not the same knowledge needed for a hunter-gatherer society. Take most NYC natives out and dump them in the Kalahari desert and see who is "smarter", they or the :primitive" !Kung who live there.

 

3. WG Solheim II, An earlier agricultural revolution. Scientific American, April 1972 in Scientific American, The Origins of Technology.

 

Now it is your turn: please document the stories of visitors who taught the early civilizations their technology. What were your sources for this statement?

[bascule]

Just wanted to say I did a little research and I was way off on this thread. Thanks for pointing me in the right direction everyone.

[JonM]

 

Again' date=' our [b']technological[/b] development is exponential. But that is NOT intelligence. Technology, in evolutionary terms, is a very small adaptation: the ability to make tools to make tools. An incremental step from chimps and other species that can make tools. But a step that has enormous results.

 

I wasn't talking about our intelligence, I was talking about the development of humans, the steps we took to get where we are today. The transition from simple lives to complicated lives. Technology is part of this. It also includes our ideas, our creativity, our imagination, our emotions etc...

 

If a baby that was born 70,000 years ago were to be raised today, that person would grow up for the most part just as "smart" as the average person.

 

And the actual process of our ancestors making tools, working with thier hands, using logic did spur thier creative thought, ingenuity, and the rest of that great stuff that separates us from our ancestors.

[bascule]

Okay, I've done quite a bit more reading on the rapid evolutionary event I was curious about... the "Great Leap Forward" which occured 40-50,000 years ago. According to Dawkins it occured some 10-50,000 years after the initial development of language.

 

Anyway, this New York Times article seems to cover the issue fairly well:

 

http://query.nytimes.com/gst/health/article-page.html?res=9503E0DF173CF936A25754C0A9659C8B63

 

Bower birds are artists, leaf-cutting ants practice agriculture, crows use tools, chimpanzees form coalitions against rivals. The only major talent unique to humans is language, the ability to transmit encoded thoughts from the mind of one individual to another.

 

Because of language's central role in human nature and sociality, its evolutionary origins have long been of interest to almost everyone, with the curious exception of linguists.

 

As far back as 1866, the Linguistic Society of Paris famously declared that it wanted no more speculative articles about the origin of language.

 

More recently, many linguists have avoided the subject because of the influence of Noam Chomsky, a founder of modern linguistics and still its best-known practitioner, who has been largely silent on the question.

 

Dr. Chomsky's position has ''only served to discourage interest in the topic among theoretical linguists,'' writes Dr. Frederick J. Newmeyer, last year's president of the Linguistic Society of America, in ''Language Evolution,'' a book of essays being published this month by Oxford University Press in England.

 

In defense of the linguists' tepid interest, there have until recently been few firm facts to go on. Experts offered conflicting views on whether Neanderthals could speak. Sustained attempts to teach apes language generated more controversy than illumination.

 

But new research is eroding the idea that the origins of language are hopelessly lost in the mists of time. New clues have started to emerge from archaeology, genetics and human behavioral ecology, and even linguists have grudgingly begun to join in the discussion before other specialists eat their lunch.

 

''It is important for linguists to participate in the conversation, if only to maintain a position in this intellectual niche that is of such commanding interest to the larger scientific public,'' writes Dr. Ray Jackendoff, Dr. Newmeyer's successor at the linguistic society, in his book ''Foundations of Language.''

 

Geneticists reported in March that the earliest known split between any two human populations occurred between the !Kung of southern Africa and the Hadza of Tanzania. Since both of these very ancient populations speak click languages, clicks may have been used in the language of the ancestral human population. The clicks, made by sucking the tongue down from the roof of the mouth (and denoted by an exclamation point), serve the same role as consonants.

 

That possible hint of the first human tongue may be echoed in the archaeological record. Humans whose skeletons look just like those of today were widespread in Africa by 100,000 years ago. But they still used the same set of crude stone tools as their forebears and their archaic human contemporaries, the Neanderthals of Europe.

 

Then, some 50,000 years ago, some profound change took place. Settlements in Africa sprang to life with sophisticated tools made from stone and bone, art objects and signs of long distance trade.

 

Though some archaeologists dispute the suddenness of the transition, Dr. Richard Klein of Stanford argues that the suite of innovations reflects some specific neural change that occurred around that time and, because of the advantage it conferred, spread rapidly through the population.

 

That genetic change, he suggests, was of such a magnitude that most likely it had to do with language, and was perhaps the final step in its evolution. If some neural change explains the appearance of fully modern human behavior some 50,000 years ago, ''it is surely reasonable to suppose that the change promoted the fully modern capacity for rapidly spoken phonemic speech,'' Dr. Klein has written.

 

Listening to Primates

Apes' Signals Fall Short of Language

 

 

At first glance, language seems to have appeared from nowhere, since no other species speaks. But other animals do communicate. Vervet monkeys have specific alarm calls for their principal predators, like eagles, leopards, snakes and baboons.

 

Researchers have played back recordings of these calls when no predators were around and found that the vervets would scan the sky in response to the eagle call, leap into trees at the leopard call and look for snakes in the ground cover at the snake call.

 

Vervets can't be said to have words for these predators because the calls are used only as alarms; a vervet can't use its baboon call to ask if anyone noticed a baboon around yesterday. Still, their communication system shows that they can both utter and perceive specific sounds.

 

Dr. Marc Hauser, a psychologist at Harvard who studies animal communication, believes that basic systems for both the perception and generation of sounds are present in other animals. ''That suggests those systems were used way before language and therefore did not evolve for language, even though they are used in language,'' he said.

 

Language, as linguists see it, is more than input and output, the heard word and the spoken. It's not even dependent on speech, since its output can be entirely in gestures, as in American Sign Language. The essence of language is words and syntax, each generated by a combinatorial system in the brain.

 

If there were a single sound for each word, vocabulary would be limited to the number of sounds, probably fewer than 1,000, that could be distinguished from one another. But by generating combinations of arbitrary sound units, a copious number of distinguishable sounds becomes available. Even the average high school student has a vocabulary of 60,000 words.

 

The other combinatorial system is syntax, the hierarchical ordering of words in a sentence to govern their meaning.

 

Chimpanzees do not seem to possess either of these systems. They can learn a certain number of symbols, up to 400 or so, and will string them together, but rarely in a way that suggests any notion of syntax. This is not because of any poverty of thought. Their conceptual world seems to overlap to some extent with that of people: they can recognize other individuals in their community and keep track of who is dominant to whom. But they lack the system for encoding these thoughts in language.

 

How then did the encoding system evolve in the human descendants of the common ancestor of chimps and people?

 

(cont'd)