Why humans are so distinct from other species?

[Angrboda]

Grass. Silicon. Fire.

Without these three things we would be still climbing trees and picking ants out of ant holes with sticks.

It is all about brain size/capacity...

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When grass started to mass grow, making large grass plains and such, it forced apemen from the trees simply because the trees were far fewer and far between and so they had to venture out onto the plains to find food.
As such hunched over and with a tail is not ideal and so slowly we evolved to stand on two legs. This was primarily for two reasons, 1st being that it allowed us to look out over the grass for danger and the 2nd being that we could reach up into trees for food.
This is significant because walking upright on two legs uses less effort, not by much but still, then walking on all fours.
Because we use less effort to move around we were consuming more calories (well, the same but less was going to the effort of moving around). The extra calories that were no longer used for movement then went to growth, brain growth.

Silicon is significant because it's soft, you can chips bits off and form crude tools.
Suddenly you have a hammer or knife. You can kill larger prey, more food, more calories, more brain growth. You can make shelter, protecting you from the elements, reducing calories spent protecting you from the elements.

Fire. Fire is the biggy. Without fire, we wouldn't have made it past the stone age.
Cooking things greating increases the amount of calories that food produces. Thus, our brains were able to rapidly grow.
We became very smart.

Grass, again, with our new found intellect we were able to go from foragers, to hunters, to now farmers.
A hunter/gather requires (something around, i can't remember exactly) 10km^2 area in order to survive, where as a farmer requires only a fraction of that.
This means we were able to fit more people on the same amount of land.
Grass is significant here because that is what was grown, wheat and suger and other grass based food.

By now man has ventured across landbridges and migrated around the world.

The difference however is that the Middle East, northern Africa had these grass plants that they could farm. They also had animals easy to domesticate. Goats, cows and such. This is why life skyrocketed in this location where as other cut off locations, such as the Americas, lagged behind.

With all these new foods and requiring far less effort to acquire them and in far smaller space, our brains continued to grow.

Soon small towns/cities were errected across egypt and the middle east.
With small cities comes specalization. Trade. Instead of having to do everything myself, I could focus on being a fantastic pot maker and trade my work for other things I need such as food. This is basic principle of economics today, effeciency.
Soon trade spreading ideas from Egypt to Greek etc... with that comes more growth etc.. etc.. etc..

The rest is history.

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"What a bunch of hooey."


I think you've got entirely too much teleology in your evolutionary just-so story. I'm tolerant of adaptationist arguments (although they make me irritable), but the existence of a trait requires more than the postulation of a potential benefit (and many of your hypotheticals are very, very weak. [grass; what about the aquatic ape theory?]). Admittedly, I've done likewise in my span, but I think, perhaps, one should concentrate on finding selectional pressures and not simply potential benefits. (As well as specifics; if the possibility of potential advantage is the yardstick, it's difficult to explain why other animals haven't evolved to take advantage of the same benefits.) Beyond that, your arrows of causality tend to swing wildly.

I think Min has the nut of it. While I contend that we have evolved specific social behaviors which result in greater instrumental utility, these behaviors themselves are not in and of themselves categorically different in terms of a cognitive ability than any other set of social behaviors which another species might employ to less spectacular results. The result is what's so distinctive, not the mechanism that produced it, as, if my contention is correct and the result is caused by the properties of the social behaviors, and not by any significantly distinctive cognitive ability, then we are not distinctive; just different. (ETA: It occurs to me there are other examples of this split between the impressiveness of the result and that of the mechanism. Army ants, a bee colony, and a beaver damn come to mind.) [And I'll note that while it's a popular notion that man has unusual reasoning abilities, relative to the animal kingdom, I hold just the opposite view, that our so-called "rational" abilities are more myth than reality. That necessarily shapes my estimate as to whether even if we have more intelligence, that makes us distinct as I view that component's contribution to our behavior (rational intelligence and abstract reasoning) as not really contributing substantially to our behavior. [And note, if all that brain increase is a result of producing a linguistic capacity, that does make us distinct along that dimension, but I rather suspect that's not the dimension of interest to most advocating our distinctiveness. As a side example, there was an experiment in which they taught some dolphins to perform a specific trick when shown a symbol on a placard. One of the symbols meant, "improvise." They showed that symbol to two dolphins simultaneously. At first attempt, the dolphins submerged and surfaced with no real event. The dolphins were shown the symbol again. Both submerged, and when they resurfaced, the two dolphins did the same trick in tandem. That to me is prima facie evidence that they can communicate, and that our notions of animal communication are an argument from ignorance. Moreover, there is a group of about a half dozen monkey species that travel together in the rain forest. They have evolved such that they are able to interpret each other's calls such that if one species signals "danger above!" the other species understand that. Is our ability to communicate within our species superior to the ability to communicate with other species in our immediate environment? You tell me.]

[Mister Agenda]

Chimps have an average IQ around 40. I know IQ isn't fully equivalent to intelligence, but the average human is about 2.5 times as smart as the average chimp. Chimp IQs over 70 have been recorded. The difference is very significant, but not astronomical. Interestingly, chimps nurtured by humans since infancy have significantly higher IQs than less-domesticated chimps.

As apophenia points out, our instinctive teaching of our young is highly significant and is a large part of the difference between us being the most clever animal and being the most clever animal that builds supercomputers. Go back 40,000 years and the relative technological achievements of chimps and humans would not be in nearly such high contrast.

We're much smarter than chimps, but not so much smarter that it's evolutionarily mysterious, and our technological achievements are dependent on knowledge and infrastructure developed over our lifetime as a species through our cultures, not a function of sheer intelligence. If we weren't around and chimps were, chimps would the cleverest animal. We are around, and there's nothing on earth that we know runs a higher IQ, so it's us. At least for a few more years.

[Minimalist]

Chimp IQs over 70 have been recorded.

Hmmm..... if chimps designed the tests I wonder how we would score?

[Severan]

I'd agree with CapnAwesome. We are VERY distinct. We are capable of destroying almost every single species on the planet, but we are a product of these species. Do you see animals talking to eachother about plans to build a nuclear missile? Do you see dogs and cats making mountains out of limestone? Do you see them make their own clothes, or cook food over a fire? Do you see them capable of destroying us? No. We are probably the most powerful thing in the universe (other than the big bang and twinkies ) and we are the only living thing on earth that understands molecules, atoms, cells, etc. All living things do things for one purpose: Reward, and survival. The only reason those chimpanzees can understand 3,000 words is because we taught them that they need to know that for a reward. Animals understand NOTHING. They just go along with nature and evolution. You know what's sad? If it wasn't for us, their ass' wouldn't be saved from the supernovae that is about to happen in 6 Billion years. All I have to say, is they better be thankful that we're their only chance of survival, and we'll help them out. I believe that our survival is more important than theirs, because we're the only damn species we know of that can possibly prevent the end of the universe. We are the only ones that can harness science for the better condition of the universe. We may be small in this large universe, but trust me, it's very possible that humans may never go extinct.

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Any thoughts on why humans differ so much from other species in terms of intelligence?

We aren't. We just like to think we are.

MM

However, we're the only animals to think we are smarter than the others.

[Question Mark]

However, we're the only animals to think we are smarter than the others.

I don't know about that. It's not like we can ask other animals their opinions of themselves.
In the Hitchhiker's Guide to the Galaxy, for example, Dolphins and humans both thought themselves superior to the other based on the same criteria but having different perspectives as to what constituted greatness in those criteria, ie. man believed that building projects, war, &c. made them great, whilst dolphins just splashed around in the water, where as dolphins viewed splashing around made them superior to man and his wars and buildings.

[Angrboda]

We're also likely the only animal to invent religion. That's got to count, like, ten internets against us.

[Cato]

Sorry, I'm late to this game. I think the evaluation of intelligence needs to be reassessed. I'll allow Ridley Scott to speak for me:

"You know Burke, I don't know which species is worse. You don't see them fucking each other over for a goddamned percentage."

[Anomalocaris]

The things that distinguish us are an emergent property of the interaction between building blocks of behavior. The building blocks of our behaviors are individually an emergent property of our organic neurological chemistry. We can reduce our distinction by arguing that since the building blocks of our behavior are individually not too different from those of many other animals, and therefore we are not very different from chimpanzees or dolphins. But we can also extend the argument and claim since our organic neurological chemistry is little different from a horseshoe crab, therefore we are not very different from horseshoe crab, or a velvet worm, or a flat worm.

Ultimately, we are all neutrons, protons and electrons, so we are little different from saw dust.

In biology, these is a camp called lumpers, and a camp called splitters.

Human = saw dust would be lumping carried to obscure extreme.

You see where this is going.

Yet much as both we and gorilla are not much different from saw dust in some way of seeing, it is we who count the gorillas we didn't kill and whether that number represent enough genetic diversity for these to be gorillas in 100 years, and not the gorillas us.

Clearly the difference in emergent property is these.

So the distinction is the emergent capacity to let us count, organize, to learn and graspmmore complex behaviors.

[Severan]

The things that distinguish us are an emergent property of the interaction between building blocks of behavior. The building blocks of our behaviors are individually an emergent property of our organic neurological chemistry. We can reduce our distinction by arguing that since the building blocks of our behavior are individually not too different from those of many other animals, and therefore we are not very different from chimpanzees or dolphins. But we can also extend the argument and claim since our organic neurological chemistry is little different from a horseshoe crab, therefore we are not very different from horseshoe crab, or a velvet worm, or a flat worm.

Ultimately, we are all neutrons, protons and electrons, so we are little different from saw dust.

In biology, these is a camp called lumpers, and a camp called splitters.

Human = saw dust would be lumping carried to obscure extreme.

You see where this is going.

Yet much as both we and gorilla are not much different from saw dust in some way of seeing, it is we who count the gorillas we didn't kill and whether that number represent enough genetic diversity for these to be gorillas in 100 years, and not the gorillas us.

Clearly the difference in emergent property is these.

So the distinction is the emergent capacity to let us count, organize, to learn and graspmmore complex behaviors.

We're likely the only animals who know that we're made of neutrons and protons.

[Mister Agenda]

Something that took us tens of thousands of years to discover probably shouldn't be counted in the 'innate distinction from chimps' column. For that we've still got mainly 60 points of average IQ, teaching our young, pointing, and complex language.