Human Intelligence

[MAUIHORSE]

Why is it with so many millions of different life forms on planet earth that only Homo Sapiens have evolved higher intelligence?
If Darwin was right and all life forms evolve to survive then what better survival mechanism could there be than higher intelligence? The ability to create weapons and tools. Linear thinking. Cognitive thought.
Why only humans?
What are the physical differences in our brains compared to chimpanzees or apes that give us this intelligence, imagination, creativeness, spoken language???????
Is it programmed into our DNA?

[CanadysPeak]

Why is it with so many millions of different life forms on planet earth that only Homo Sapiens have evolved higher intelligence?
If Darwin was right and all life forms evolve to survive then what better survival mechanism could there be than higher intelligence? The ability to create weapons and tools. Linear thinking. Cognitive thought.
Why only humans?
What are the physical differences in our brains compared to chimpanzees or apes that give us this intelligence, imagination, creativeness, spoken language???????
Is it programmed into our DNA?

I should think that a matter of perspective, at least in terms of survival. What other species is capable of weaponizing ebola, for example? Whoops, there goes the species. I'm no biologist, but I should think some bacteria and simple plants have us beat all hollow. I think it safe to say that Homo xxx has survived less than 10 million years so far.

And, remember, we are the ones defining intelligence. It might be a rigged game.

[neuro]

Why is it with so many millions of different life forms on planet earth that only Homo Sapiens have evolved higher intelligence?

Well, one may well wonder that one species did make it against all odds...

If Darwin was right and all life forms evolve to survive then what better survival mechanism could there be than higher intelligence?

I fear that this is a standard misconception on evolution: species do not evolve to survive. Random (genetic) changes occur in populations. If such changes happen to favor survival, they may stabilize introducing genetic heterogeneity in the population; under environmental pressure and competition for resources the advantageous traits may prevail (selection), so that the species will "have evolved".
Lots of if's and very low probabilities.

Why only humans?
What are the physical differences in our brains compared to chimpanzees or apes that give us this intelligence, imagination, creativeness, spoken language???????
Is it programmed into our DNA?

look at this image
As you can see, our brain has grown for about 2,300,000 years (until about 100,000 years ago) by a factor of almost 10. What has grown most markedly is cerebral cortex. Cerebral cortex development increases the possibility of multiple combined analysis of sensory information, fine movement elaboration, memory storage and recall, imagination and prefiguration, and therefore elaboration of complex strategies, complex elaboration of spatial relations leading to perception of order, periodicity, unicity / multiplicity, cardinality, ordinality; multiple combined analysis of information sets the stage for symbolic capability; enhanced elaboration (not perception) of sounds and fine movements of larynx and tongue, combined with such symbolic capability create the possibility of language.
Curiously enough, the differences in DNA are much less relevant than one would imagine (about 1% between apes and ourselves).
The fact is you would not be able to easily "read" in DNA such paramount differences in cerebral cortex development. The trick is in regulation of neuronal proliferation, migration and axon guidance (guiding the thin fibers that the neuron emits to reach and contact other neurons). I don't know whether this can give you an idea, but proteins control the functioning of cells, genes dictate the recipe for proteins and some proteins regulate genes (switch them on/off, thereby producing or not other proteins): in this dynamic picture, during development specific genes are turned on in specific cells or areas and then switched off after an appropriate time; thus, if a gene that produces proliferation of neurons during development is switched on in a cortical area and kept functioning for a longer time, this is sufficient to determine an increase in the population of neurons in that area, or where those neurons are bound to migrate. So you can generate paramount differences in size and organizations of neuronal circuits by simply changing the timing of switching on/off the same genes.
More or less like saying that all Beethoven's nine symphonies are written using the same 7 (or better 12) notes...

[neuro]

by the way, MAUIHORSE,
I would not be so confident that through higher intelligence we possess the best "survival mechanism".
Most species are probably much more fit than we are (e.g. cockroaches).
Simply, there appears to (momentarily) be an ecological niche we can inhabit pretty well (until we do not manage in destroying it ourselves).
You do not need to be particularly fit to survive in the absence of competition for food and resources.
Maybe, the "advantage" is mostly that of versatility and capability to adapt to almost any climatic and environmental situation on the Earth. Many species do not have this capabiity. Some even have such specific needs that they are confined to small and particular niches.
Well, cockroaches live almost everywhere because they are particularly robust and little demanding. We do because we adapt ourselves to the environment or the latter to ourselves.
Rather than considering intelligence an advantage to survival, we could look at it as something which more or less repays us of the discomfort of carrying around such a heavy head and the disadvantage of having to eat a lot of calories just to keep the brain working.
Intelligence is just a reasonable bargain.
Actually, thogh there is not general agreement on this, scientists have proposed that Neardertal was extinct due to a climate change, because he did not have sufficient technology to survive the icy climate, whereas sapiens did. But it is not clear whether they just disappeared or were "absorbed", since about 4% of genetic variants in old-continent people appear to derive from Neandertal, suggesting that some extent of interbreeding occurred. So, we are, to a greater or smaller extent, bastards (if not hybrids, since it has not been defined yet whether sapiens and Neandertal were two distinct species or subspecies or races)

[Forest_Dump]

This is definitely one of those perennial topics that can be fun to speculate about almost precisely because there are no final answers yet. We do know that brains are hungry beasts that require a huge amount of nutrition to keep going. So many critters probably didn't grow bigger brains because the slight increase in brain size wasn't enough of a plus to make up for changes in the diet necessary, if that was even possible. For now, I think our best bet is to look at when increases in brain size appear relative to other things and see if any correlation can be a causal correlation.

Looking at the fossil record, bipedalism can be ruled out because walking on two legs came long before any real increase in brain size (that is assuming we are not counting the relative braininess of most primates).

The use of stone tools also seems to predate growth in brain size but not by much since A. garhi, possibly the earliest user of stone tools was about as brainy as a chimp. It is possible therefore, that the use of stone tools was what aided nutrition enough to allow brain growth.

The odd thing, though, is that during the time that the fossil record shows growth in brain size, there is not much solid evidence for what good it did. While the brain size was growing fastest, there is not much evidence for changes in stone tool use. Some but not much.

Most now agree that truly human complex thought didn't really appear until possibly as recently as 50,000 years ago. This could have been more than 1-200,000 years after modern brain sizes were reached.

There is tons of literature on this and I think it might be worth your while to hunt some of that down.

[Forest_Dump]

Actually I just remembered something I had read earlier this spring (sorry, those notes have been put away and can't get the original references now). Apparently some of the genes related to brain growth are also linked to other traits such as (I think) kidney function. If so, then it is possible that increased brain size was not initially selected for but something else was (i.e., kidney function if I have that right) and therefore the increase in brain size was more of an accidental side benefit of something else, but made possible by (accidentally again?) improved nutrition.

[cladking]

It is not intelligence that distinguishes man; it is speech.

Yes, we are a little more clever than most other species and most individuals can outthink most animals but the intelligence difference is nominal and has played little role in the developement of technology and the species. Human history is a history of massive gains after increases in our ability to use speech. We didn't even have human characteristics until the supersized speech center became established. Writing propelled us further since with books a student was no longer wholly dependent on the teacher. Paper (papyrus) allowed writing to be useful. The printing press made books common. Now electronic communication will cause another leap.

Just like Newton we stand on the shoulders of giants. The giants just aren't as intelligent as we take them for.

[neuro]

It is not intelligence that distinguishes man; it is speech.
Yes, we are a little more clever than most other species and most individuals can outthink most animals but the intelligence difference is nominal and has played little role in the developement of technology and the species.

I bet you are kidding....
I do not know of any animal that can produce (not use, but imagine, prefigure, invent and produce) an instrument to perform a task which cannot be performed using hands and available objects.
Do you really think that intelligence is not needed for speech (for language, I mean, not for "speaking" as a parrot does)?
An incredible number of different areas in the brain are necessary for correct elaboration, use, comprehension and production of language; there is no "supersized speech center".
The step from symbolic capacity to language is a big one, but it is not the only one

[cladking]

No. I'm usually serious and literal.

Most things people consider intelligence really aren't or are also represented by other animals. Even termites make air conditioned cities. People aren't accustomed to looking for signs of intelligence in animals and quick to ascribe more intelligence in humans than what exists.

No other species has a complicated language and it's human ability to pass down learning from one generation to another that is our strongest survival characteristic. Humans not only adapt their enviroment but can adapt to their enviroment because of language. Most intelligent humans have all sorts of tricks they can do that other animals can't but this is partially need, partially learning made possible by language, and partially intelligence.

The ability to use language probably fascilitates thought in itself. Most thought is in words and following the structure and rules of language leads to better processing of ideas and concepts. Humans are pretty good at the manipulation of complex concepts. This is at least related to intelligence. But there's no evidence of which I'm aware to suggest that people have significantly more inate ability to comprehend nature or their situation than other animals.

[neuro]

dear cladking, I keep having a feeling of surreality...
Possibly you are a creationist and think that god gave us language, and a bit, but not much, more intelligence than to other species.
If you are not, then I invite you to think how language may have developed in humans, if not as a consequence of a series of behavioral, cognitive, elaborative, associative, imaginative, inductive, deductive, strategic and symbolic capacities, which cannot be defined but "intelligence"...

Then, if your aim is to dismantel the belief that us human are very intelligent and the other animals are very stupid, then this is another story. And I would like to reassure that this kind of belief is not particularly present in this forum, so no great battles are needed.

[cladking]

dear cladking, I keep having a feeling of surreality...
Possibly you are a creationist and think that god gave us language, and a bit, but not much, more intelligence than to other species.
If you are not, then I invite you to think how language may have developed in humans, if not as a consequence of a series of behavioral, cognitive, elaborative, associative, imaginative, inductive, deductive, strategic and symbolic capacities, which cannot be defined but "intelligence"...

Then, if your aim is to dismantel the belief that us human are very intelligent and the other animals are very stupid, then this is another story. And I would like to reassure that this kind of belief is not particularly present in this forum, so no great battles are needed.

That's OK, a lot of people feel about the same way talking to me. ;)

Intelligence didn't evolve in man and neither did language. One day a mutant was born with a much larger speech center than others and (s)he was the first (wo)man. Being the only one around with advanced communication skills was an advantage since the others were clever enough to learn some of it. Cooperative behavior allowed the trait to spread to offspring and soon the talkers simply populated the earth. This was probably around 40,000 years ago and humans have been off to the races ever since.

Intelligence is probably decreasing in man since it's no longer important for survival. It's often more a liability than an asset.

I never thought of myself as a creationist before but in a very convoluted sort of way I am. This will become more clear as some of my crackpot theories come to light.

[dragslaye]

I bet you are kidding....
Do you really think that intelligence is not needed for speech (for language, I mean, not for "speaking" as a parrot does)?
An incredible number of different areas in the brain are necessary for correct elaboration, use, comprehension and production of language; there is no "supersized speech center".

I volunteer as a art teacher for children with special needs. Some of this children have severe mental retardation, basically they are not smarter than a dog, and yet they are able to speak perfectly.

No other species has a complicated language and it's human ability to pass down learning from one generation to another that is our strongest survival characteristic. .

there are a lot of species which poses both complex communication patterns, and are able to pass down knowledge.

[CanadysPeak]

. . . they are not smarter than a dog, . . .

Interesting comparison. I have a monitor for the National Weather Service. They employ highly educated meteorologists, high-powered Doppler radar, numerous weather stations about the area, etc. I also live with a very strange dog. When the dog gets up suddenly and heads to the basement, where she has a dark, sheltered corner, I can expect the weather bulletin alarm within minutes; it seldom fails and, when it does, the dog was right, the NWS was wrong. Now, the dog cannot tell me whether it is a severe thunderstorm or a tornado or heavy hail that is approaching, and she never alerts on flash flooding warnings (we live on a high hill), but . . .

[cladking]

there are a lot of species which poses both complex communication patterns, and are able to pass down knowledge.

I think our definitions of "complex" must be different. A bee can tell it's fellows where the flowers are and a baboon might engage in complex interplay involving communication but there's no evidence that any of these other "languages" include more than a couple hundred "words". Many human concepts and knowledge simply couldn't be phrased in any other animal "language". There is a passing down of learned behavior in other animals but this tends to be done without language. A cat teaches her kittens to hunt but there's no philosophy that goes along with it.

A great deal of all animal behavior is mostly or entirely instinct. Man has instincts as well but these are usually overruled by higher brain functions or learning. Of course not all animal behavior is instinct and they do display intelligence, learning, curiousity, etc.

[wolfhnd]

There is evidence that elephants may have better memories than humans.
http://news.softpedia.com/news/Why-Elep ... 7563.shtml

Cetaceans are perhaps more "evolved" than humans.
http://www.scientificamerican.com/blog/ ... han-we-are

The truth is we don't have any way to know what intelligence is outside of a specific context. One thing is certain however and that is that the "artificial" intelligence that language and writing enables is a distinct advantage for humans. Evidence suggests that humans raised in isolation never fully develop the traits we associate with intelligence. Stripped naked and dropped in a wilderness would you pick a survival book for the specific habitat or a knife? In humans like other social animals intelligence seems to be a collective trait.

[psionic11]

Here's a few thoughts to synthesize and perhaps reconcile the differing views offered so far in this thread:

The evolutionary and developmental aspects of the brain can be traced across the different animal clades enough to show a pattern -- mammalian brains are more evolved than birds then reptiles, etc. The cerebral cortex and its specialized centers like symbolic representation and stored memory come to mind.

Mammals can be divided into 3 major branches --
1) the monotremata (echidnas, duck-billed platypuses, and a couple other egg-laying mammals)
2) marsupials (bear their young not quite fully developed)
3) the rest of us placental mammals (mammals that carry their unborn until birth)

Only the placental mammals have a corpus callosum -- the bundle of connections that let the two halves of the brain communicate with their counterpart in the other half. Very significant. Not to mention the already mentioned memory capacities of other mammals. The cerebral cortex is almost a strictly mammalian invention... the more wrinkles, the more capacity. Rat cortex = smooth; cat cortex = slightly wrinkly; human cortex = very wrinkly. And our cerebellum is not too shabby either. Gracile animals generally have more developed cerebella.

A precursor to speech and language (and music, painting, body language, empathy) is the capacity to represent the environment not only for what it is now, but also for what it could be -- this is mental simulation, imagination, planning, symbolism, what have you.

Why humans rather than chimps or whales or elephants? In a few words, it's the very fortunate synergism of a handful of key components -- tongue, larynx, hands, speech, longevity, clans and culture -- and the exponentially additive effect that generations of humans have built.

An individual human is impressive. But a human or group of humans that carry their collective legacy...? Unmatched. Even by billion-year-old bacteria.

So while any particular species may have some super-specialized niche that trumps any single human adaptation (cheetah speed, thermophilic Geyser bacteria, anti-freeze fish, immortal fungus/lichen symbiotes, salamander regenration, thousands of offspring in one mating season) -- it is the very flexibility and capacity of generations of human intelligence that gives us a superior competive and successful advantage.

After all, what is survival? The ability to adapt to your environment to sustain yourself and propagate your kind. And in an abstract way, that is exactly what better intelligence affords, yes?

[cladking]

After all, what is survival? The ability to adapt to your environment to sustain yourself and propagate your kind. And in an abstract way, that is exactly what better intelligence affords, yes?

No. In other animals there should be a link between intelligence and survival but it would be much less pronounced in man. Survival is about who's the hunter and who's the hunted. It's as often as not about pure blind chance. The rabbit won't be eaten by the fox if it's on the other side of the woods. Species have to adapt to their enviroment or change it to suit or they will suffer population declines or extinction. (it is primarily population declines which is evolution).

But intelligence is something that has meaning only in the individual. It doesn't matter if foxes are smarter than rabbits if a specific rabbit is more intelligent than the fox hunting it. While intelligence is an asset it rarely has much relevence to extinction or increasing population of a species.

Intelligence is man is grossly overestimated and intelligence in animals is somewhat underestimated. The importance and utility of intelligence is overestimated as well. We see our success as the result of intelligence while it's primarily language.

[psionic11]

After all, what is survival? The ability to adapt to your environment to sustain yourself and propagate your kind. And in an abstract way, that is exactly what better intelligence affords, yes?

Species have to adapt to their enviroment or change it to suit or they will suffer population declines or extinction. (it is primarily population declines which is evolution).

Which is what I stated above. Survival is dependent on your ability to adapt to your environment (as well as being in an environment that sustains life in the first place -- food, temperature, air, etc).

Note that I did not say survival = intelligence. More precisely, better intelligence is *one*, not *the only*, mechanism which better enables that animal to adapt. Other enablers are being able to outdistance predators, being unseen/undetectable to your predators, going where your predators cannot, reproducing as a species faster than your species's predators prey upon you, etc.

But intelligence is something that has meaning only in the individual. It doesn't matter if foxes are smarter than rabbits if a specific rabbit is more intelligent than the fox hunting it. While intelligence is an asset it rarely has much relevence to extinction or increasing population of a species.

Intelligence is an objective trait long before it is a subjective trait. Mammals aren't sitting around patting themselves on their backs saying "my brain is more developed than you pathetic reptiles." That costly but more evolutionarily adapted gray matter is one of the bigger reasons for the diversity and survival of mammals after the last great extinction event some 300-350 million years ago. That, along with fur and warm-bloodedness, better smell and vision and hearing, milk and care of the young.

It's important also to make the distinction as to what is "intelligence." It is not merely the capability for language. Simpler organisms like invertebrates and plants largely deal with immediate environmental factors -- water and nutrient acquisistion, reproduction in favorable conditions, use of built-in mechanisms to respond to less-than-favorable conditions. More complex animals deal with not only those factors, but also many more fluid circumstances that involve other competitors in similarly complex scenarios. This adaptation to and thriving in variable ecosystems is one way of defining "niches." Many niches are simply the result of a species physically evolving to thrive in that niche -- geyser bacteria, ocean bottom-feeders, coral reefs, mosquitoes. But many niches require not only a physical adaptation but also the wherewithal to deal with new circumstances that may threaten your very life. Animal intelligence is one essential way in dealing with these, especially if your competitors are varied and intelligent as well.

Intelligence is man is grossly overestimated and intelligence in animals is somewhat underestimated. The importance and utility of intelligence is overestimated as well. We see our success as the result of intelligence while it's primarily language.

While I strongly agree that intelligence in animals is grossly underestimated, I disagree with the statement that mankind's intelligence is overestimated. That opinion shows a strong personal bias. The objective evidence for sophisticated intelligence is not made so much on an individual case-by-case basis but for humanity as a whole -- atomic energy, chemistry (including medicines and synthetic materials manufacture), electronics and communications, multi-modes of travel, countless large networks and organizations ranging from international flights to trade protocols to higher learning institutions to the business world to the Internet.

But perhaps a greater testament to the success of human intelligence is the historical evidence for mankind's many methods of adapting to, or the outright adaptation of, the Environment itself -- some of it detrimental as well -- fire; weapons and tools; hunting and agriculture and water-management; wood and metal and clay use; human and animal slavery for farming and materials production; exploitation of plants and animals for food and clothing and tools and storage; travel and transport and trade; etc.

Knowledge-sharing across time and distance (that is, language) of course plays a fundamental role in each of those endeavors. And the use of our hands is another grossly underestimated factor for all these successes. Without language we would not be as advanced as we are today, but without hands we would be much, much closer to our animal brethren. Talking deer can only accomplish so much to tame the environment around them...

[Paralith]

There are a couple of things in this thread that I would like to caution the participants about.

Firstly, I think there are a lot of statements being made in a rather factual manner that, to me at least, are not obviously factual, and I would enjoy seeing some supporting references. Cladking, your statements in particular stick out to me. While it is true that many of the qualities and characters that we once thought unique to humans can be found to a certain degree in many other animals, often the extent and complexity of those characters is objectively and quantitatively greater in humans than it is in other animals, and this can be measured with a variety of behavioral and psychological tests that many researchers have been conducting on many animals, especially non-human primates, for a long time now. (And of course, in many specific cognitive aspects these animals can outperform humans. But I think most people in this discussion have largely agreed that we are talking about a more general domain kind of intelligence.) I'm also impressed by the specificity of your dates, and I'm not sure I would agree. However, if you feel that you have read and researched data that strongly suggests otherwise, do share it with us. I'm afraid I'm going to have to be slightly hypocritical at the moment and not provide sources of my own until a later date - I'm in a place where internet access is rare and slow.

Secondly, and this may just be my perception, there is a lot of talk about "more highly evolved" and traits that favor survival. I think we need to avoid thinking about things in terms of being more or less evolved. To evolve simply means to change; random genetic mutation is just as much evolution as natural selection is. And many animals that have been through large amounts of natural selection, and thus become highly specialized to a very specific niche, have long since gone extinct. I think it is inaccurate to equate amounts of change with an index of long-term survivability. And though I think several of you have seen me give this little schpeal before, when it comes to natural selection, survival is really rather secondary. If in dying right here, today, you can cause more of your offspring to successfully go on to reproduce themselves than any of your competitors can, then that is what natural selection will favor. Surviving longer is only helpful if by doing so you can increase your lifetime reproductive success - and this type of strategy is certainly one that many groups of animals appear to have developed, especially primates (who, among mammals, have longer lifespans than expected for animals of their body size). But its important to remember that reproduction is still the key.

[avanover]

Why is it with so many millions of different life forms on planet earth that only Homo Sapiens have evolved higher intelligence?
If Darwin was right and all life forms evolve to survive then what better survival mechanism could there be than higher intelligence? The ability to create weapons and tools. Linear thinking. Cognitive thought.
Why only humans?
What are the physical differences in our brains compared to chimpanzees or apes that give us this intelligence, imagination, creativeness, spoken language???????
Is it programmed into our DNA?

I expect that we might evolve into enlightened beings (rather than sentient beings). Perhaps we will be able to create our own universes with our very thoughts. So that in the event of danger in this universe, we could just create another. Perhaps the highest survival mechanism is immortality and we will eventually attain this. Who can know for sure though? Can one our ancestors conceptualize that it will evolve into a human?