Why haven't other organisms evolved humanlike intelligence?

[gravenewworld]

From an evolutionary molecular biology perspective, this may be controversial in some circles and it isn't my field of expertise, but one idea that has been floated out there is related to the absolutely unique ways that humans postranslationally modify proteins. For example, sialic acids became prominent late in evolution, primarily in animals of deuterostome lineage which comprises the vertebrates and some “higher” invertebrates that emerged at the Cambrian expansion. With rare exceptions, sialic acids are not generally found in plants or in most prokaryotes or invertebrates. There have been a few reports of sialic acids in mollusks, such as octopus and squid, and insects such as Drosophila. Genes structurally related to those involved in vertebrate sialic metabolism have been reported in insects and plants, and even in Archaea. Sialic are now often found in membrane macromolecules of microorganisms with newer lab techniques. Overall, it appears that sialic acids may be a more ancient Precambrian invention, but they were then either eliminated or used only sparingly in many lineages—finally flowering into prominence only in deuterostome lineage. Genetic evidence also suggests that the original invention of sialic acids may have derived from homologous gene products that synthesize keto-deoxyoctulosonic acid (Kdo). Certain strains of bacteria can contain large amounts of sialic acids or other 2-keto-3-deoxynononic acids in their capsular polysaccharides and/or lipooligosaccharides. Some of these bacteria are pathogenic and cell-surface sialic acids protect them from complement activation and/or antibody production. Thus, although definitive proof has not been obtained, the possibility of gene transfer from host eukaryotes exists. Interestingly, there is wide variation in sialic acid expression and complexity within deuterostome lineage, with the sialome of echinoderms appearing very complex and that of humans being more simple. However, expression of hydroxylated forms of sialic acids and O-acetylated sialic acids is highly conserved in deuterostomes, although exceptions exist, such as the lack of hydroxylated sialic acids in man, chicken, and some other birds.


So what does this have to do with evolution and why haven't other species involved intelligence like us? The most prominent example in this case is related to polysialylic acid (PSA) addition on neural cell adhesion molecule 1 (NCAM1). NCAM1 is a cell surface adhesion protein on neurons that is vitally important for memory, learning, and plasticity. NCAM1, along with another protein called L1, interact homophilically to fasiculate neurons together. However, when PSA is added to NCAM1, NCAM1 and L1 can no longer interact--in otherwords, PSA addition to NCAM1 is another layer of control over the way neurons can remodel themselves. The importance of PSA on NCAM1s can not be overstated. In addition to regulating the way neurons in the adult brain can remodel, NCAM1s and PSA regulate the way neurons move throughout the body espeically in neural crest-derived tissues during development. Additionally, genetic variation of ST8SIA2, the gene responsible for polysialylation of NCAM1, is associated with increased susceptibility to bipolar disorder, schizophrenia, and autism. More and more evidence piles on all of the time for the role of polysialylation in the brain development.

To visualize PSA, see here (top polymer):

http://glycoforum.gr.jp/science/word/gif9909/gt-c01-fig1.gif


During metabolism of glucose into sialic acids in organisms other than huamans a gene named CMAH encodes for the enzyme that hydroxylates sialic acid into Neu5Gc the structure of which is here:

http://www.glycoforum.gr.jp/science/glycogenes/06/1.gif


As was stated above, one of the things that makes us uniquely human is the fact that we do no have Neu5Gc on our cells. The explanation for this is due to an inactivating exon deletion in the CMAH gene that occurred after our last common ancestor with the African great apes. If you can see what I'm getting at, the monomers that make up PSA in humans are not hydroxylated, and PSA in humans is not made out of a polymer of Neu5Gcs. The importance of this slight chemical alteration is quite profound--many experiments have been performed that have shown that when Neu5Gc is engineered onto the surface of human cells, you can induce immune responses. And as was previously discussed, PSA modulation of NCAM1s has a profound influence on brain development, learning, and memory. Why haven't animals evolved human like intelligence? One reason could be due to either lack of proper sialic acid metabolism and/or deletion or mutational impairment of their CMAH gene which is responsible for their production of Neu5Gc that may be preventing their brains from rewiring themselves to develop human like intelligence.

 

[Pythagorean]

I haven't dived deep into this thread, so I apologize if I'm restating something, but human intelligence has a lot of contributing factors. Some we share with other animals (the versatility of the neocortex, for instance). But others are unique (afaik) to humans, such as well-known jaw muscle "maladaptation" (presumably) that allowed for larger brain growth. The molecular story here involves MYH16.http://www.nature.com/news/2004/040322/full/news040322-9.html

 

[Acid92]

"Human-like" intelligence, and I think this is most usefully defined in the evolutionary-biological sense as the ability to solve novel problems (as opposed to merely recurring ones) in the organisms environment via "learning" (see article below) -or to put it another way, take most species out of their natural habitat and they tend to go extinct but throw a group of even ancient humans nearly anywhere on land on the planet and they just may survive-, is obviously an absolute advantage in survival. The problem is getting there in the first place since evolution is a continuous process. Here is a pertinent article I found that describes some research addressing just this very question. The research was on the relationship between "learning ability" in animals like fruit flies and fitness: turns out that "learning ability" actually has fitness costs.

http://www.nytimes.com/2008/05/06/science/06dumb.html?8dpc=&pagewanted=all

My impression of all this in quantitative terms: suppose we could describe evolutionary fitness as a function of "learning ability"/intelligence, then if increased intelligence has fitness costs (of course you could eventually evolve ways to deal with those costs but local costs if you will, will always exist), the function would be fraught with local extrema in spite of the fact that the general trend will be a positive relationship between fitness and intelligence. Once you get to a local maxima on that function, evolving higher intelligence would actually be maladaptive, and all else being equal, natural selection has no reason to go any further. To top it all, as the article points out too, increasing intelligence is merely one way to deal with the problem of a changing environment. So all in all, "human-like" intelligence appears to be an incredibly adaptive trait in an "absolute" sense but that is only after you have the trait, evolving it in the first place is an entirely different thing.

 

[Doofy]

I'm eagerly awaiting your updated commentary once you have a "bad trip."

Been there. Unpleasant to say the least. Some people claim there's more to be gained from a bad trip than a good one... but I am not one of those people, lol.

Our primate ancestors spent plenty of time on the ground whereby they would have come in contact with said mushrooms before coming down from the trees. I highly doubt there's any connection. Is it true that the most popular current model is that environmental changes roughly 8 mya drove many primates out of the trees. The evolutionary consequence of this, however, was not a "rocket-propelled" brain growth due to the injestion of psychedelics, it was the bipedalism that resulted so they could see above the grasslands on the savanna.

How sure are people about that grasslands thing? I've heard talk of us having stood upright because of starting to wade through water like this actually:

which seems to vibe with the whole aquatic ape thing (http://en.wikipedia.org/wiki/Aquatic_ape_hypothesis) but I don't know if the experts have decided they don't like this one.

Bipedalism freed the hands to manipulate objects, create tools, etc., which gave a selective advantage for regions of the brain to develop to facilitate a more hierarchically complex manipulation of these objects. It had nothing to do with getting stoned. What about the hundreds of other quadrupedal mammalian species wandering around the planet at that time consuming magic mushrooms? Why didn't they develop human-like intelligence?

Let's see if I understand... walking upright -> more freedom for hands -> brain develops more to get more hand control -> ? -> advanced reasoning / imagination / etc.

Seems straightforward up until the -> ? -> but gets vague at that point. Could it be that mammals other than primates lacked whichever brain receptors the psilocybin binds to?

 

[Drakkith]

which seems to vibe with the whole aquatic ape thing (http://en.wikipedia.org/wiki/Aquatic_ape_hypothesis) but I don't know if the experts have decided they don't like this one.

From the article you linked:

Extant scientific consensus is that humans first evolved during a period of rapid climate fluctuation between wet and dry, and that most of the adaptations that distinguish humans from the great apes are adaptations to a terrestrial, as opposed to an earlier, arboreal environment. Few paleoanthropologists have explicitly evaluated AAH in scientific journals, and those that have reviewed the idea have been critical. The AAH is one of many hypotheses attempting to explain human evolution through a single causal mechanism, but the evolutionary fossil record does not support any such proposal. The proposal itself has been criticized by experts as being internally inconsistent, having less explanatory power than its proponents claim, and suffering from the feature that alternative terrestrial hypotheses are much better supported. The attractiveness of believing in simplistic single-cause explanations over the much more complex, but better-supported models with multiple causality has been cited as a primary reason for the popularity of the idea with non-experts.[3]

It is extremely unlikely that the AAH is responsible for human evolution, either by itself or as a primary factor.

 

[DiracPool]

Some people claim there's more to be gained from a bad trip than a good one...

The only insight I ever gained from having a bad trip is a clear understanding that it sucks to have a bad trip, and that it's much better to find natural ways to get your buzz on other than ingesting psychoactive substances.

Let's see if I understand... walking upright -> more freedom for hands -> brain develops more to get more hand control -> ? -> advanced reasoning / imagination / etc.

Seems straightforward up until the -> ? -> but gets vague at that point.

There's a large body of literature linking hierarchically sequenced manual manipulations and hierarchically organized cognitive processes. I suggest reading Jean Piaget's work or some of the many neo-Piagetian scholars/authors that abound today. There's even a Journal published by the Jean Piaget Society if you want to peruse that: http://www.journals.elsevier.com/cognitive-development/

Could it be that mammals other than primates lacked whichever brain receptors the psilocybin binds to?

Not likely. Neurotransmitters and receptors are highly conserved in mammals, which is why we can feel confident that experiments conducted on these animals have relevance to human brain function. My guess is that there's probably a fair number of empirical studies on the effects of psilocybin and LSD on animals published out there if you look around.

 

[Doofy]

The only insight I ever gained from having a bad trip is a clear understanding that it sucks to have a bad trip, and that it's much better to find natural ways to get your buzz on other than ingesting psychoactive substances.

Actually I consider it totally natural behaviour, it's not even confined to our species, but enough of the psychedelics talk before I derail the thread too much.

There's a large body of literature linking hierarchically sequenced manual manipulations and hierarchically organized cognitive processes. I suggest reading Jean Piaget's work or some of the many neo-Piagetian scholars/authors that abound today. There's even a Journal published by the Jean Piaget Society if you want to peruse that: http://www.journals.elsevier.com/cognitive-development/

Sounds interesting and I will certainly have a read about it when I've got time. What is really meant by 'hierarchically sequenced/organized'? Is that about, say, wrist motion -> multi-finger motion (gripping hold of something) -> individual finger motions? And as for the hierarchy of brain activities...?

Does this Piaget stuff mean that, as a rule of thumb, animals that have to perform more intricate/complex motions with their body parts should be smarter? How do dolphins fit into this with their clumsy flippers?

Not likely. Neurotransmitters and receptors are highly conserved in mammals, which is why we can feel confident that experiments conducted on these animals have relevance to human brain function.

Ah, that does make sense.

My guess is that there's probably a fair number of empirical studies on the effects of psilocybin and LSD on animals published out there if you look around.

I haven't really looked for them but I have heard plenty of talk about early ones being conducted badly and deliberately for government propaganda purposes, and their illegality meaning research into them has been very handicapped since then.

 

[bobze]

How sure are people about that grasslands thing? I've heard talk of us having stood upright because of starting to wade through water like this actually:

which seems to vibe with the whole aquatic ape thing (http://en.wikipedia.org/wiki/Aquatic_ape_hypothesis) but I don't know if the experts have decided they don't like this one.

Junk to say the least;
[/PLAIN]
aquaticape.org

Why have I done this site?
Two reasons:

1) Because AAT/H proponents ask why don't people take their theory seriously as science, and the way you take a theory seriously as science is to examine it for accuracy and criticize it where it falls short, because...

2) "Valid criticism does you a favor" Carl Sagan, page 32 of The Demon-Haunted World (1995).

I am doing what many AAT/H proponents -- including its principal proponent, Elaine Morgan -- have repeatedly claimed they want done: treating the AAT/H as befits a serious scientific theory.

Accepting any new theory uncritically is foolish. When doing a critique of any theory of human evolution, you check the facts the authors use to support the theory.

All scientific theories need to be examined for accuracy; it's an essential component of the process of science. I'm afraid that when the Aquatic Ape Theory is examined, it does not fare well. The AAT/H is built on many supposed facts which, when examined, do not turn out to be true. Perhaps the kindest thing would be to ignore it, but I am not that kind.

Instead I've begun an ongoing response of pointing out errors of fact, errors in theoretical understanding (which, though critically important, is more problematic because a lot of people seem to think this is waffling), and urging the theory's proponents to respond to valid objections to their theory.

A good critique on the "science" of AAH.

 

[lpetrich]

This may be something that's improbable or else difficult to evolve.

Looking at the Earth's biota, some features evolved several times, while some others evolved only once, as far as we can tell.

Multicellularity has evolved several times, but animal-like multicellularity only once. All the other instances are plantlike or funguslike or slime-mold-like.

A vertebrate-style internal skeleton has evolved only once, while various sorts of external and almost-external ones have evolved several times.

Etc.

 

[Medicol]

Evolution is not goal oriented. So our intelligence is not what it solely offers us after all. But it is a product of our adaptability to surroundings. There have been no such good conditions for other species to evolved their human-like intelligence. I'm not joking but what are we going to do if a *creature* sitting behind us is having much higher IQs than we are ? Compete, kill or co-live ? Please analyze these terms biologically.

 

[Guco]

Humans were originally endurance hunters. We might not have claws, speed or raw strength, but few animals can run as long and far as we can. You think a chimp can run a marathon?

The traits that make us good endurance hunters have also contributed to our specific intelligence:
Walking upright: does not only free the hands, but it also allows for a greater weight of the brain (the head is now on top of the center of gravity) and reduced energy required for movement (which frees up more energy for the brain). This may have also contributed to our vocal abilities.
Naked skin: it's not that we lost hair just because we can wear clothes, our naked skin gives us increased control of our body temperature by making sweating much more effective. That's important because the brain is very sensitive to overheating.
Tactics of hunting: Endurance hunting is usually social hunting (wolves for example). It requires social coordination (tactics+long range sound communication during a hunt) and social rules on how to share food. Because our sense of smell isn't that good, we rely on being able to interpret things like tracks or broken branches to follow an animal. This also requires being able to empathize with an animal, to be able to understand where it would flee when being chased.

Then if you go back further to our likely origin in forests (where most primates live) there are some additional traits we picked up there:
Multiple highly evolved sensory organs: this is something we have in common with most primates. Because primates generally live in trees it requires good eyesight (for 3d navigation), hearing (because trees also block sight and predators) and touch (very useful when you are swinging through trees). Our sense of smell is not quite as impressive but still decent.
Our diet: fruit and meat, all high in energy, gives time for leisure, makes it easy to feed children.
Understanding of place and time: required to find food in forests. Apes know when and where they can find fruit, they remember specific trees and the time when the fruit is good to eat.

Finally, we don't know if the evolution of human-like intelligence is rare or not until we find many other planets with animal life on it that have been around for at least as long as Earth has. n=1 until we do.

 

[Syed Ammar]

Humans were originally endurance hunters. We might not have claws, speed or raw strength, but few animals can run as long and far as we can. You think a chimp can run a marathon?

The traits that make us good endurance hunters have also contributed to our specific intelligence:
Walking upright: does not only free the hands, but it also allows for a greater weight of the brain (the head is now on top of the center of gravity) and reduced energy required for movement (which frees up more energy for the brain). This may have also contributed to our vocal abilities.
Naked skin: it's not that we lost hair just because we can wear clothes, our naked skin gives us increased control of our body temperature by making sweating much more effective. That's important because the brain is very sensitive to overheating.
Tactics of hunting: Endurance hunting is usually social hunting (wolves for example). It requires social coordination (tactics+long range sound communication during a hunt) and social rules on how to share food. Because our sense of smell isn't that good, we rely on being able to interpret things like tracks or broken branches to follow an animal. This also requires being able to empathize with an animal, to be able to understand where it would flee when being chased.

Then if you go back further to our likely origin in forests (where most primates live) there are some additional traits we picked up there:
Multiple highly evolved sensory organs: this is something we have in common with most primates. Because primates generally live in trees it requires good eyesight (for 3d navigation), hearing (because trees also block sight and predators) and touch (very useful when you are swinging through trees). Our sense of smell is not quite as impressive but still decent.
Our diet: fruit and meat, all high in energy, gives time for leisure, makes it easy to feed children.
Understanding of place and time: required to find food in forests. Apes know when and where they can find fruit, they remember specific trees and the time when the fruit is good to eat.

Finally, we don't know if the evolution of human-like intelligence is rare or not until we find many other planets with animal life on it that have been around for at least as long as Earth has. n=1 until we do.

Hey, I THINK THIS IS THE PERFECT REPLY! EXCELLENT MAN.

 

[james oliver]

It seems like it would be a huge advantage to their survival, so why haven't other organisms evolved such? Why are humans the only organisms capable of doing things like creating complex technology and using complex language?

The answer to me simply is humans assume we are the most intelligent. It's all relative. Too use "survival" as some type of gage - sharks have been around for 400 million years (humans - 7 million). We are not even on the top of species with the longest life spans...

 

[DiracPool]

The answer to me simply is humans assume we are the most intelligent. It's all relative. Too use "survival" as some type of gage - sharks have been around for 400 million years (humans - 7 million). We are not even on the top of species with the longest life spans...

Looking back through this thread, there seems to be a confounding of the concepts of "intelligence" and "survival." Intelligence is simply one tool of many that can be helpful in survival. It can also be helpful in not surviving, as in being so smart and clever that you construct a bomb to wipe out your species, or you become so successful at being successful that you overpopulate and dry up (literally in California) your resources, etc.

On the other hand, slime molds and extremophiles will probably be around long after were gone, and I wouldn't consider them "intelligent" in the same way Einstein was intelligent. But to answer the OP's initial query, it's not because a slime mold might survive a nuclear holocaust and we won't that it did not evolve human intelligence, it is because it didn't need to evolve human intelligence in order to survive. Humans evolved from primates, who had a relatively cush existence for a long time living up in the trees away from ground predators. At some point a population of these primates were (most likely) forced down from the trees and had to survive in east Africa amidst a panoply of dangerous and more fit quadrupedal carnivores. Natural selection utilized and shaped what was available to help those primates adapt and survive that specific situation, which was specifically the exploitation of the hand that the primates had already had well developed for swinging through the trees.

A smile mold, sea sponge, juniper tree, or hammerhead shark wasn't under these same selection pressures that hominoids were under, and this is why they did not evolve human-like intelligence.

 

[stefanow]

Intelligence per se (= understanding, predicting and acting accordingly) is not a prerequisite for survival. Countless mindless living beings have been around for millennia and will probably outlive us for all intents and purposes. However, there’s one huge evolutionary advantage in human intelligence in particular. Human beings don’t just die; they also know that they are destined to die one way or another. That leads to a constant struggle for power in advance by any means necessary, even when no apparent enemy is on sight, in a desperate and conscious attempt to avoid annihilation. Death is life’s single most ingenious invention in order to assure that the struggle for survival, aka evolution, will never reach to an end – and human intelligence its most advanced realization.

 

[julcab12]

'Why' is bit hard to get a satisfying answer. So well go with comparative.. We don't deviate much from macaque monkeys in term of brain similarities but whatever cause the lateral frontal pole prefrontal cortex-- which is related to multi-tasking and decision making; to boost more neural connections-- tells us that we think a lot during our course of evolution more than any other animals recorded. Other variable includes breeding causing different brain characteristics that freed us form the limitation of that part of the brain like in selective breeding on dogs (Some breed of dogs are dumber than the other). Similarly dolphins might have same complexity of situation like us but on a different environment including a wide range of protein-changing aspect on their physique leading to variation of brain potential.

 

[DiracPool]

'Why' is bit hard to get a satisfying answer. So well go with comparative.. We don't deviate much from macaque monkeys in term of brain similarities but whatever cause the lateral frontal pole prefrontal cortex-- which is related to multi-tasking and decision making; to boost more neural connections-- tells us that we think a lot during our course of evolution more than any other animals recorded. Other variable includes breeding causing different brain characteristics that freed us form the limitation of that part of the brain like in selective breeding on dogs (Some breed of dogs are dumber than the other). Similarly dolphins might have same complexity of situation like us but on a different environment including a wide range of protein-changing aspect on their physique leading to variation of brain potential.

I don't know what you're talking about Julcab. The macaque prefrontal cortex is about 11% the prefrontal portion of their total cortex, whereas it's about 30% in the human.

"Similarly dolphins might have same complexity of situation like us but on a different environment including a wide range of protein-changing aspect on their physique leading to variation of brain potential"

I'm guessing you're not an authority on Dolphin cognition, so please give us documentation about this "dolphins might have same complexity of situation like us" stuff.

 

[julcab12]

I don't know what you're talking about Julcab. The macaque prefrontal cortex is about 11% the prefrontal portion of their total cortex, whereas it's about 30% in the human.
.

http://labroots.com/user/news/daily/id/58/title/similarities-and-differences-between-human-and-monkey-brains

..
"MRI scans were then performed on the same number of macaque monkeys to compare the same sections of the ventrolateral frontal cortex. The research team was surprised to find that 11 of the 12 regions in the human brain had a corresponding area in the macaque brain, with significant similarity in the organization and connections between macaques and humans. The potential implication is that some human cognitive abilities may have their roots in these neural similarities.

However, one section of the human brain had no analogue in the macaque brain – an area known as the lateral frontal pole prefrontal cortex. This area of the human brain is known to have connections with decision-making and strategic planning skills, and is also associated with multi-tasking abilities."
."

>>>I'm just a reader and not an expert or even near to one. I might misinterpreted what I've read and made a bad judgement. So correct me if I'm wrong.

I don't know. I made a simple assumption here. If our brain are structured in a close proximity to other species like the case above except for lateral frontal pole prefrontal cortex-- apparent with other primates. There might be some connection or hint to how we developed such complex cognition since it is connected on the same area. Perhaps we acquire such uniqueness from products of interbreeding analogous to selective breeding like dogs showing different morphological variation of different breeds. Or our neural connection evolved gradually until it became unique to other common ancestors. Or both.
http://understanddolphins.tripod.com/dolphinbrainandintelligence.html

http://www.livescience.com/21196-dolphin-brain-evolution-intelligence.html

"More than 200 of the genes in their survey were drastically changed in the dolphins. Twenty-seven of these were involved in the nervous system (like the brain and sensory organs). There were also many changes in the genes related to metabolism (similar to changes seen in primates), which McGowen said are important because, "brain tissue uses much more energy than other tissues."

While we know these genes are associated with the brain, and this study says the genes are different in smarter animals, the researchers caution against linking them directly. Differences in the gene's "code" doesn't mean the gene actually acts any differently in the animal.

"We may not know exactly what they do yet even in humans or mice (the two most well-characterized mammals from a genetic perspective), much less dolphins; however, their function in the brain points to their importance," McGowen said. "Probably, changes in these genes could have led to the amazing cognitive capacity seen in dolphins — it definitely points in that direction."

>>>How come dolphins evolved such a sophisticated brain compared to other aquatic animals? Does experience of being once a mammalian land dweller gave an impact in their cognitive evolution. Can a diversified and complex environmental situation produced such type of brain structure (which is inevitable to marine mammals)?

All I'm saying is their might be an argument that our ancestors must be exposed to complex environmental situation (similarly to dolphins lineage). And we by "some chance" choose more to adapt differently compared to other animals; Led to some modifications in our brain and physical evolution in contrast to other common ancestries.

 

[DiracPool]

http://labroots.com/user/news/daily/id/58/title/similarities-and-differences-between-human-and-monkey-brains

..
"MRI scans were then performed on the same number of macaque monkeys to compare the same sections of the ventrolateral frontal cortex. The research team was surprised to find that 11 of the 12 regions in the human brain had a corresponding area in the macaque brain, with significant similarity in the organization and connections between macaques and humans. The potential implication is that some human cognitive abilities may have their roots in these neural similarities.

However, one section of the human brain had no analogue in the macaque brain – an area known as the lateral frontal pole prefrontal cortex. This area of the human brain is known to have connections with decision-making and strategic planning skills, and is also associated with multi-tasking abilities."
."

An easy way to view brain evolution in mammals is that of 3 stages. The one primitive region of the brain that's relatively conserved among all mammals is the 1) Orbitofrontal cortex, which includes most of the olfactory system. The second, 2) the ventrolateral prefrontal cortex, is also conserved among all mammals but begins to show development in higher primates. The third, 3) the rostrolateral prefrontal cortex, shows exaggerated development only in humans, and presumably other hominin species via endocast analyses.

The lateral frontal pole prefrontal cortex you mention I'm guessing is the rostrolateral PFC I'm familiar with. This region is most specifically identified with Brodmann's area 10 in primates, and it's incorrect to say that there's no analog in the macaque brain. In fact, there are no known unique structures in the human brain that aren't found in any other mammalian brain. What distinguishes humans is the exaggerated development of the "trilogy" of prefrontal cortex I listed above, and in that order.

http://www.ncbi.nlm.nih.gov/pubmed/11241188

As far as the dolphins are concerned, this is more of a psychological question than a comparative neurobiology question. I've studied the comparative neuropsychology and neurobiology of mammals for over 20 years, and my conclusion is essentially that of Macphail's, there are 2 types of mammalian intelligence, human and nonhuman.

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=6790468

Dolphins and bonobo chimps, etc. may be on the upper end of the nonhuman "intelligence" scale, but it's discontinuous with human cognition, which is based on a fundamentally different mechanism.

 

[Torbjorn_L]

To sum up the recent activity on this thread, it hasn't progressed much beyond the recognition that there is selection bias here (we define human-like intelligence, we are the first, et cetera) and that we need more data. (Either by waiting long enough or by finding similar ETIs.)

The hypothesis that humans are "special" in the brains, neurons et cetera is both too weak (each species will have particular traits that define them) and too strong (specific intelligence will have specific physiological correlates). Again, we need much more data to uncover if there is a difficult bottleneck here.

More generally, intelligence evolved early, so it isn't a difficulty as such. Same goes with legs. That they are used differently (combinatorial language in humans; wings and fins in many lineages) is to be expected. Maybe the question is, of what use is humanlike intelligence?

When humanlike intelligence started to evolve, what made us the most successful animal by biomass today wasn't particularly important or difficult. (Tool use combined with sociability, both seen elsewhere.)

On the other hand, if Asia hadn't had plants and animals that were suited for cultivation and spread we hadn't made it this far either, so that we would put the question. Maybe the condition is simply that a planet needs to have a large longitudinal continent.

 

[julcab12]

The lateral frontal pole prefrontal cortex you mention I'm guessing is the rostrolateral PFC I'm familiar with. This region is most specifically identified with Brodmann's area 10 in primates, and it's incorrect to say that there's no analog in the macaque brain. In fact, there are no known unique structures in the human brain that aren't found in any other mammalian brain. What distinguishes humans is the exaggerated development of the "trilogy" of prefrontal cortex I listed above, and in that order.Dolphins and bonobo chimps, etc. may be on the upper end of the nonhuman "intelligence" scale, but it's discontinuous with human cognition, which is based on a fundamentally different mechanism.

Ok. Make sense. What are the proposed factors or mechanism involved in that exaggerated development of prefrontal cortex? Can other hominids have a similar brain profile(exaggeration) just like us. Can other species be able to achieve the same feat even in principle. How did we end up wiht that type of brain. Is it genetic abnormality or gradual evolution.

Out of the jungle of brain variations. How can mammal---(specially human) been able to achieved such characteristics compared to other animal. "Ok, tools, language and socialization, but other animals used tools etc(crow) too... Ok, we've developed a better utilization of tools..How? bec of our evolved physical profile is ergonomically good and efficient. How? Bec that is how nature shape our physique while other animals adapted differently. How are we drawn to tools? Curiosity and by accident.

 

[DiracPool]

Ok. Make sense. What are the proposed factors or mechanism involved in that exaggerated development of prefrontal cortex? Can other hominids have a similar brain profile(exaggeration) just like us. Can other species be able to achieve the same feat even in principle. How did we end up wiht that type of brain. Is it genetic abnormality or gradual evolution.

The answer to your question is the hand. In an earlier post I laid out the argument, but to recap briefly, it was bipedalism that freed the hominin hand and the frontal lobe developed to finely manipulate the hand, which proved to be an immense aid in survival for hominins. If you look at the homunculus of body representation in the primary motor strip, you'll see that the hand is grossly overrepresented. But what's hidden is the enormous representation of hierarchical manipulation skills found in the prefrontal cortex.

"Can other species be able to achieve the same feat even in principle."

Certainly, that is of course how we achieved it in the first place, but I wouldn't hold my breath. The closest species to us is the chimp, and it took our common ancestor on the order of 20 million years to get from the 17% prefrontal cortex to our current 30%. So you're not going to see any human-like intelligence coming out of another species for quite some time, and if you do, it's probably going to be long after contemporary humans are long extinct. Why? because history has shown us that we like to kill off our competition before it gets too smart. There was a time several million years ago when there were several hominin species alive simultaneously. That is, until Homo sapiens sapiens killed them all off. Even today, we've just about driven all the great apes into extinction, and they're no threat to us at all. We need to be careful, because we'll never get that back.

 

[Lok]

Humans not as "advanced" as chimps in short-term memory ...

I've seen this interesting test a while ago. It also said something about the part of the brain responsible for this fast photographic memory as being overtaken by speech ( a very fast cognitive ability of humans) during the childhood learning phase. Feral children appear to be much better at the task in the video than normal people. At least as I remember, I need to find some links to this.

The evolutionary advantage of speech and communication is probably the most important result of a higher intelligence and our learning phase is very big compared to most animals. Also information would not only be transmitted through visual examples (as a kitten learns from observing it's mother) but could include spoken cues like "big green fruit bad". Which would be the starting point of a society where knowledge can be shared among individuals not closely related to each other.

Also intelligence gives a better use of the surrounding environment as one could choose a good vantage point or hideout out of more factors. One can seen that rabbits are somewhat agoraphobic (cool evolutionary instinct) and prefer borrowing and some animals are claustrophobic and prefer outrunning (e.g. wild pigs dislike being cornered). While these instincts serve well, they do not differentiate much between two hideouts or surfaces. So learning and connecting the different factors that make an environment advantageous is a great evolutionary benefit.

 

[enorbet]

I think it is entirely unfair and ill conceived to speak of evolutionary advantage when referencing a few generations. Stephen Hawking related this mentioning that as a species with abstract intellect we created language, and then written language that has completely altered (sped up) evolution in one set of aspects. The other sets, the subconscious drives, including blindly following powerful and/or charismatic leaders and a no-limits acquisition directive without any concern for consequences, among others could possibly result in an event somewhat like handing a loaded pistol to a 4 year old. Carl Sagan said one of the most compelling reasons for SETI was to ask a more advanced civilization, "How did you do it?"

Cockroaches, Sharks, horseshoe crabs and jellyfish are but a few of the species that have survived essentially in their current form for up to 0.5 Billion years. We have a long way to go before we reach that milestone unless one conveniently ignores that as part of "evolutionary success".

We became intelligent out of necessity driven by climate change and the diminishing availability of the foods we commonly ate. As Larry Niven quipped "You don't need to be smart to sneak up on a leaf". It remains to be seen if that will serve us well in the long run. We can speculate all we want but until it is fait accompli we are in no position to judge.

 

[Torbjorn_L]

I think it is entirely unfair and ill conceived to speak of evolutionary advantage when referencing a few generations.

Not in the biological sense, it is advantages (positive fitness) and disadvantages (negative fitness) and none (near neutral drift) that drives evolution over generations.

What you drag in is the confounding between intelligence and survival that DiracPool identified above. 99.9+ of species goes extinct, and a mammalian species has an average survival time of a million years. So we are gone soon in any case.* But hominids are exceptions of wide diversity, long lifetimes (H. erectus ~ 2 million years) and success (half the mammal land biomass I think). That spells success due to advantages.

Cockroaches, Sharks, horseshoe crabs and jellyfish are but a few of the species that have survived essentially in their current form for up to 0.5 Billion years.

That is wrong, I believe. They aren't the same biological species, and while it is hard to see that in the fossil record due to stasis of body plans (so sometimes taken as same fossil species) in some lineages it has become evident by genome sequencing.

*It used to be that Anatomically Modern Human was 0.2 Myr. But I believe the latest Pääbo et al result implies the evolutionary rates have been overestimated, and the species is perhaps twice as old. Unless we become as successful as Erectus, we are now entering old age as a species.

 

[enorbet]

There was a time several million years ago when there were several hominin species alive simultaneously. That is, until Homo sapiens sapiens killed them all off. Even today, we've just about driven all the great apes into extinction, and they're no threat to us at all. We need to be careful, because we'll never get that back.

I agree with much of what you have posted in this thread but I do take considerable objection to the sentence in Bold above. AFAIK there is no evidence that Homo sapiens killed off similar species and there is some evidence that cooperation was commonplace. Recent results from genome sequencing as well as archeological evidence support that Neanderthal and Sapiens lived alongside each other for thousands of years. I think this makes sense when one considers that in those early days in which Man was not exactly at the top of the food chain, safety in numbers had to be a powerful argument. It's not that I am offended by the "Murderous Ape" concept ( I am, but that is of no consequence ) since the reality is just as ugly in that Enslavement is much more likely. There is always a market for cheap.

Not in the biological sense, it is advantages (positive fitness) and disadvantages (negative fitness) and none (near neutral drift) that drives evolution over generations.

I did say "few generations". It is fairly common knowledge that Evolution is not goal driven and that what is an advantage under one set of conditions may actually be a disadvantage under others. Case in point - For hundreds of millions of years large size was a distinct advantage, at least in most environments. That all changed, a few times in fact, with catastrophic events like volcanos and impacts, but many studies suggest that substantial numbers of species were already "on the way" out from more subtle changes in environment.

What you drag in is the confounding between intelligence and survival that DiracPool identified above. 99.9+ of species goes extinct, and a mammalian species has an average survival time of a million years. So we are gone soon in any case.* But hominids are exceptions of wide diversity, long lifetimes (H. erectus ~ 2 million years) and success (half the mammal land biomass I think). That spells success due to advantages.

I don't see this as confounding but rather the most fundamental measuring stick. I don't see how any other measure other than numbers of years that what we can call a species has existed, can even remotely compete. In biological and evolutionary terms, the continuation of a species is success, right? The key to success, or at least the top contender, is adaptability, and while intelligence has been a key player in that for our species it hasn't always been the case.

In addition to the above references I made about the conflict between subconscious urges (very long term programming) and the effect of intelligence, especially through the medium of complex language bridging generations, there are also a large number of individual high level civilizations that have failed due to external events (drought and flood are majors) and also internal ones such as some people argue that lead pipe and lead eating and drinking utensils affect on such fantastic leaps in civilization such as found in Ancient Rome. In these cases it is sometimes lack of understanding what has made the world go mad, but it is also likely that doggedly sticking to "the old ways" played a part as well.

Not only do we embody internal conflict caused by unbalanced evolution (the above mentioned affect of language bridging generations vs/ the "merely" physical and long term programming) we also are capable of housing a great number of conflicts and contradictions in one body that somehow coexist somewhat comfortably. Although this does give us more options for adaptability, it also highlights how it is possible in both short term and long term, and in no way limited to just the cosmic roll of the dice of mass extinction events, for a single attribute to be both an advantage and a disadvantage.

That is wrong, I believe. They aren't the same biological species, and while it is hard to see that in the fossil record due to stasis of body plans (so sometimes taken as same fossil species) in some lineages it has become evident by genome sequencing.

*It used to be that Anatomically Modern Human was 0.2 Myr. But I believe the latest Pääbo et al result implies the evolutionary rates have been overestimated, and the species is perhaps twice as old. Unless we become as successful as Erectus, we are now entering old age as a species.

There is another thread on this forum asking the question "is our DNA the same as it was 20K years ago?" and of course it is not completely identical because Evolution continues. Similarly a great number of long living and long surviving species are changed some little bit over time just like us, but we would recognize a modern human from 20,000 years ago as human just as we recognize a horseshoe crab from 200,000,000 years ago for what it was. or sponges or yeast, etc.

Bottom line, by whatever standard you wish to employ, modern humans, even ancient progenitors, are newbies on the scene and it remains to be seen whether our version of intelligence is sufficient an advantage, or if the long term benefits outweigh both the disadvantages (there are a few) and our attributes not based in intelligence (response) vs/ instinct (reactions).

Like all here I revel in intelligence and am dismayed that underneath our tech achievements we are so few steps down from the trees and it seems less prominent in so much of our species (who are so resistant to change, so driven by ancient ways and instincts and therefore less adaptable) but to assume that our brand of intelligence is a key factor in what will carry us through, is not Science. Since we are so far apparently somewhat unique we have no frame of reference and are left with speculation.

That speculation is also a tangent to OP. That question is "Why?" not "whether or not". As has been noted a series of slow but powerful climatic events led to our evolving a combination of attributes, including intelligence, and such long term powerful events have not happened since. However we may be creating those conditions again, largely due to instincts that include competition over cooperation and insatiable greed, trumping brain power, but using it to further those urges. That said, even a dramatic climate change similar to the long term ones that fueled our progress along intelligence lines, is not guaranteed to repeat that performance, either in us, or in other species. Thus, it remains to be seen.

 

[Torbjorn_L]

the "Murderous Ape" concept

According to Pinker the violence has dropped historically. Today the murder rates, with a majority urbanized population where violence is perhaps twice the agrarian - is comparable to chimps. (There was a recent paper on that, so I compared the rates best I could.) Even bonobos can be comparably murderous, the statistics was both tentative and small, but the upper limit such as it was is about the same.

Chimps (and perhaps bonobos) may be the "Murderous Ape". I doubt humans, heavily self-socialized, is.

It is fairly common knowledge that Evolution is not goal driven and that what is an advantage under one set of conditions may actually be a disadvantage under others.

I didn't get that was your point in the previous comment. Still, we know that at least some of the tool set that we have evolved has lasted 2-3 million years (complex tool use).

I don't see this as confounding but rather the most fundamental measuring stick.

Then we have to agree to disagree. Intelligence is useful, but an evolution stopper it is not. If anything, the expanded population has made natural selection more effective (as measured in selective sweep rates) as it can pick up smaller fitness "signals" among random biological "noise".

just as we recognize a horseshoe crab from 200,000,000 years ago for what it was. or sponges or yeast, etc.

I was nitpicking on "species", and have to repeat: By a similarity or lineage description they would be horseshoe crabs, but our modern species they would not be.

That said, even a dramatic climate change similar to the long term ones that fueled our progress along intelligence lines, is not guaranteed to repeat that performance, either in us, or in other species. Thus, it remains to be seen.

My first comment on the thread went towards this. Rip out the bias of being first et cetera, and biologists would still say that it won't happen again, at least not in this biosphere. Meanwhile elsewhere, the astrobiologists have just seen (twice!) that planetary populations have a dual distribution, either 4-8 (which we belong to) or just 1 (or 0 for about half the stars). That implies an evolution from having an initial rich population to a last survivor.

In that sense our system is rare, it had a Jupiter/Saturn pair where Saturn was sufficiently massive to place Jupiter after the Jupiter-Saturn resonance of the Nice model. Add a rarity of complex life (took a while from oxygenation of the atmosphere until the mitochondrion event) and another rarity for language capable intelligence, and you will be pretty much alone in the galaxy at your specie's moment in time (~ 1 million years, presumably also in similar complex ecologies). I get ~ 10^3 concurrent civilizations, so ~ 3*10^-7/ly^3 (approximating the Milky Way as a (flat) cylinder) or ~ 100 ly to the next ETI at the optimistic end.

 

[David Carroll]

Because if there was an organism called Nikilapu, they would ask "Why haven't other organisms evolved Nikilapu-like intelligence?"

 

[enorbet]

According to Pinker the violence has dropped historically. Today the murder rates, with a majority urbanized population where violence is perhaps twice the agrarian - is comparable to chimps. (There was a recent paper on that, so I compared the rates best I could.) Even bonobos can be comparably murderous, the statistics was both tentative and small, but the upper limit such as it was is about the same.

Chimps (and perhaps bonobos) may be the "Murderous Ape". I doubt humans, heavily self-socialized, is.

I didn't get that was your point in the previous comment. Still, we know that at least some of the tool set that we have evolved has lasted 2-3 million years (complex tool use).

I'm not sure that you understand that I agree. I don't buy the "Murderous Ape" concept. AFAIK essentially all species are capable of murder, even bunnies and kitties and one-celled animals, certainly bacteria and virii :). I don't see that as a defining term, just a necessary attribute of survival for any lifeform

Then we have to agree to disagree. Intelligence is useful, but an evolution stopper it is not. If anything, the expanded population has made natural selection more effective (as measured in selective sweep rates) as it can pick up smaller fitness "signals" among random biological "noise".

I am utterly confused by this reply. I don't see any comment by anyone anywhere in this thread that contends that intelligence is an "evolution stopper". In my case, I stated exactly the opposite that "Evolution continues".

I was nitpicking on "species", and have to repeat: By a similarity or lineage description they would be horseshoe crabs, but our modern species they would not be.

Again I am somewhat confused. If I understand what you are saying as "horseshoe crabs won't become intelligent" I think that is exactly the point regarding the nature of evolutionary success and the assertion that intelligence is a major advantage across-the-board in evolutionary terms. Horseshoe crabs remain largely unchanged after at least 3 major mass extinction events. Are we able to trace what our ancestors were as of ~250 Ma?

My first comment on the thread went towards this. Rip out the bias of being first et cetera, and biologists would still say that it won't happen again, at least not in this biosphere. Meanwhile elsewhere, the astrobiologists have just seen (twice!) that planetary populations have a dual distribution, either 4-8 (which we belong to) or just 1 (or 0 for about half the stars). That implies an evolution from having an initial rich population to a last survivor.

In that sense our system is rare, it had a Jupiter/Saturn pair where Saturn was sufficiently massive to place Jupiter after the Jupiter-Saturn resonance of the Nice model. Add a rarity of complex life (took a while from oxygenation of the atmosphere until the mitochondrion event) and another rarity for language capable intelligence, and you will be pretty much alone in the galaxy at your specie's moment in time (~ 1 million years, presumably also in similar complex ecologies). I get ~ 10^3 concurrent civilizations, so ~ 3*10^-7/ly^3 (approximating the Milky Way as a (flat) cylinder) or ~ 100 ly to the next ETI at the optimistic end.

Agreed. I am aware that this is likely the best answer for the Fermi Paradox so far. I do however question the confidence that within a biosphere there will always be a "last survivor". Certainly more than a few times upwards of ~90% of all species have gone extinct, but much like the fact that humans have ~95% DNA in common with chimps confuses many people that don't understand how much room for variation is possible in that last 1-5% (not to mention the variation possible within the "similarity" of the other 95-99%) this rather ignores (or merely neglects to commonly state) the diversity of the survivors and the expansion obviously possible over eons. It may also ignore factors we have yet to comprehend. Again, it remains to be seen, and though it is illogical for me, who will be long dead, to care about the fate of Homo Sapiens, for some reason I do and I hope we beat the odds (as we now see them) and survive for ... oh... a billion years seems a nice round figure :)

 

[jim mcnamara]

Evolution has NO direction or intention nor does it have a pinnacle or a valley - it is simply an emergent process based on a simple set of "rules" imposed by physical laws. It is nothing more. Intelligence has evolved independently in Cephalopods, Cetaceans, Carnivora, and primates, for example. Ants of many species in some tropical environments constitute a majority of the biomass there. So using some of the ideas (not facts) tacitly expounded in this thread, they have "won". See: http://www.jstor.org/discover/10.2307/2989676?uid=3739816&uid=2&uid=4&uid=3739256&sid=21104928197017

There is no such thing as having "won" anything in evolution, just having survived to reproduce.

 

[Ryan_m_b]

The discussion seems to have naturally run its course and the OPs question addressed.