WHy have other species not evolved intelligence

[manchambo]

I've always had this question: why are we the only really intelligent beings on earth? Why has there not been any other species that developed along our lines to survive by ever-increasing intelligence. And by that I mean a species that we would be able to communicate with, to talk about things like life, the universe and evertyhing (not just being able to teach them the sign for bananna or fish).

Please understand that I do not ask this to in any way challenge evolution. In fact, I firmly believe evolution to be an accurate account of our development. Instead, I wonder whether the lack of evolution of other intelligent creatures might not be a sign of the divinity of our evolution.

Thoughts? Has anyone read anything good about this question?

 

[laptoppop]

This is actually quite a good question. Certainly more advanced intelligence should be a good thing, whether you are a fish, a lizard, a dog, or a whatever.

 

[gluadys]

I've always had this question: why are we the only really intelligent beings on earth? Why has there not been any other species that developed along our lines to survive by ever-increasing intelligence. And by that I mean a species that we would be able to communicate with, to talk about things like life, the universe and evertyhing (not just being able to teach them the sign for bananna or fish).

Please understand that I do not ask this to in any way challenge evolution. In fact, I firmly believe evolution to be an accurate account of our development. Instead, I wonder whether the lack of evolution of other intelligent creatures might not be a sign of the divinity of our evolution.

Thoughts? Has anyone read anything good about this question?

This is totally personal speculation on my part, but I wonder if it has anything to do with the fact that we developed the ability to speak.

It seems to me that it is highly unlikely, even with the requisite brain capacity, that something like human intelligence could have evolved without speech to spur its development.

Many other animals with a fairly high level of intelligence do not have the physical capacity for speech. Some which do have a significant capacity for producing many types of sound either do not have the requisite brain capacity (e.g. birds) or are limited in other ways by their physique (e.g. dolphins).

Of course, maybe with dolphins, the real problem is that we have not learned their language yet.

 

[laptoppop]

Supposedly (ok, my position is showing ) humans developed a larger brain as part of their evolutionary development -- so why not parrots?

 

[Mallon]

To be fair, other species have evolved intelligence. We can look at several lineages in the fossil record that develop progressive intelligence (as approximated by their encephalization quotients). Parrots, for example, develop progressively bigger brains (their EQs match those of chimps, in fact). Dolphins also develop progressively bigger brains, which is no secret. Theropod dinosaurs, on their way to becoming birds, develop larger brains as well (best exemplified by critters like Troodon or Bambiraptor).
So yes, animals have developed intelligence, just not to the same level we have (though that's debatable). Remember that evolution isn't teleological. Lineages don't evolve in any particular direction unless they have to.

 

[laptoppop]

Wouldn't increased intelligence virtually always confer an evolutionary benefit? Why should humans be different?

 

[Dracil]

Brains aren't free ya know. They have energy and development costs. Look at how many years we need to reach adulthood.

The most successful organisms aren't even us, they're insects.

 

[Mallon]

Wouldn't increased intelligence virtually always confer an evolutionary benefit? Why should humans be different?

As the saying goes, "if it ain't broke, don't fix it." Again, animals only develop intelligence if they need to. As it turns out, most species get along just fine without large brains (which are energetically expensive to maintain).
There are a few different ideas as to why humans developed enlarged brains, one of which says that the increased protein diet of humanity's closest ancestors facilitated the development of increased brain size.

 

[Deamiter]

Yeah, our brains are EXPENSIVE! Not only are they incredibly hard to give birth to, they take a ton of resources to grow and maintain.

Quite simply, intelligence is a waste of resources when resources are scarce. Yes, a bird that is a little more creative might be better able to find food, but when food is really scarce, the birds with larger brains (and greater needs) will end up dying first.

Obviously it's even more complicated than that, but that's the basics of it. Now there are some animals that ARE extremely intelligent -- perhaps even as capable as humans. But as others have said, what defines our concept of intelligence is abstract thought. Some great apes seem to be capable of many aspects of abstract thought as communicated through sign language, but without a consistant culture that reinforces it, most populations in the wild don't see a point to painting pictures and writing books when they can sit around and play and use their intelligence to help each other find food...

It's fascinating to read about what scientists can say about the intelligence of other animals and more importantly, how they come to their conclusions. It's been a few years since I really took time to read about it though so I'm certainly not the best source on the subject!

 

[jds1977]

I'd say we had more intelligence because we are a tri-une being. We have a spirit as well as a soul. Or, maybe it's the ability to reason. But, I'm looking at it from a creation and not evolutionary point of view.

 

[gluadys]

I'd say we had more intelligence because we are a tri-une being. We have a spirit as well as a soul. Or, maybe it's the ability to reason. But, I'm looking at it from a creation and not evolutionary point of view.

Well, in this case, that would not be inconsistent with an evolutionary viewpoint either.

 

[Assyrian]

Supposedly (ok, my position is showing ) humans developed a larger brain as part of their evolutionary development -- so why not parrots?

Because if they had bigger heads they would fall out of the tree.

But seriously, growing bigger brains is a high risk route to take. It demands a lot of extra resources just to make that brain tissue. It requires a lot more time devoted to raising offspring because bigger brains take longer to mature.

For humans developing a bigger brain meant weakening the jaw muscles which constricts primate skulls. The weaker jaw muscle allowed the skull to expand as other changes grew our larger brain. But that not only meant a less powerful bite, but in humans the mutation which achieved this involved a general weakening of all our muscle fibres, which are much weaker that ape's. Chimps really are a lot stronger than we are.

It can take a lot a extra intelligence before it pays off. Don't forget it is the bullies who rule the playground.

 

[laptoppop]

So how would you explain what exists in a watery environment where the weight load of a bigger brain is much much less?

I understand what is being said here -- but it seems to be a quite weak explanation, trying to accomodate the realities. It would seem to me that increased intelligence should typically give the possessor a significant advantage in competing with others for food, mates, etc. and that such an advantage would be emphasized using natural selection..... IF there were the variation to begin with.

 

[Deamiter]

So how would you explain what exists in a watery environment where the weight load of a bigger brain is much much less?

I understand what is being said here -- but it seems to be a quite weak explanation, trying to accomodate the realities. It would seem to me that increased intelligence should typically give the possessor a significant advantage in competing with others for food, mates, etc. and that such an advantage would be emphasized using natural selection..... IF there were the variation to begin with.

Well you're quite right about the advantage of intelligence -- it's certainly selected for. You're just underestimating the cost of intelligence. Besides simply adding a need for extra nutrients to feed the brain, it also requires a MUCH longer development time. Human babies are helpless for much longer than any other animal which is a HUGE disadvantage when predators are around.

The issue is no different in a watery environment. The costs are the same, and a larger body takes a larger brain to control (interestingly enough, I believe some of the larger dinosaurs had secondary brains to help control some of their systems). It is also perhaps significant that whales, dolphins and elephants are some of the most social and intelligent animals on the planet. The lack of opposable thumbs might keep them from developing tools (though elephants are rather clever with their trunks) but they do have extremely advanced social networks.

One thing to look for if you're interested in how intelligence relates to body mass is graphs that relate brain size to body mass. There's no strict linear relationship between this metric and intelligence, but it's interesting how humans fall easily on the extreme side of largest brain per mass. I'll see if I can find you one of these graphs if I have time today.

I'd like to agree with gluadys that our being created in the image of God could very well play a part (possibly a huge part) in our intelligence. I can describe the cost of intelligence (badly -- there's MUCH more than I can explain as a physicist) but as a supernatural effect, it is impossible to detect and quantify the effect of our souls on our intelligence. I'm not going to say that our intelligence is definitively due to our special relationship with God simply because I can't prove it and the Bible is rather vague about what exactly is a "soul." Just because I can't quantify it, however, doesn't mean I reject the possibility that it is very active.

You'll see me talk much more about what I DO know rather than speculating about things that nobody knows. Speculation is fun and all, but in the end it is rather useless.

 

[Xaero]

http://www.peteducation.com/article.cfm?cls=15&cat=1795&articleid=3342

"Wild birds have been observed to lay walnuts in the roadway so passing cars will crack them open."

very interesting ...

 

[laptoppop]

Totally fair. And you're right about speculation..... (but it can be fun at times <grin>).

I guess the main thing I'm seeing is that the same arguments against developing intelligence could be applied against humans developing intelligence. In terms of evolutionary theory, why should we be a special case versus all of the other animals? If its that hard, why did it work with us?

 

[Mallon]

Interesting bit I just came across here on the subject of intelligence:
http://ucalgary.ca/news/feb2007/chimp-hammers/
From my university no less.

 

[Deamiter]

Totally fair. And you're right about speculation..... (but it can be fun at times <grin>).

I guess the main thing I'm seeing is that the same arguments against developing intelligence could be applied against humans developing intelligence. In terms of evolutionary theory, why should we be a special case versus all of the other animals? If its that hard, why did it work with us?

Great question, and I have to admit the first couple pages of Google (all I have time for at the moment) offer rather incomplete discussions. I'll certainly be on the lookout for better sources, and I'll check some of my subscription services to see if I can find even better articles (though i'd have to quote limited bits to avoid violating copyright laws).

The basics center around an existing social network that exists in great apes today. When humans moved from forest to African Savannah, they evolved in an environment that didn't change for millions of years which pushed selection for a larger brain in a single direction (rather than selecting for competing traits as the environment changed). The following outlines what many of the articles I've read propose, and though it uses a bit of a controversial computer model (i.e. the model is far from proof or even strong evidence that it DID happen) the model is based on evidence and assumptions that I've found elsewhere.

Basically, I'd like you to treat this as a sort of summary (as I couldn't find a better summary) rather than a discussion of the particular model. If you don't believe me that this is reasonably representative of what evolutionary biologists are saying about the issue, do feel free (and encoraged) to do some digging of your own!

From http://www.physorg.com/news83410847.html

Not until the “cognitive explosion phase”—5 to 20 thousand generations later—does increased learning ability and cerebral capacity offer advantages. At this time, much of the population has received both genes, promoting rapid expansion of the ideas. Interestingly, the scientists found that cerebral capacity evolves more rapidly than learning ability, suggesting that potential is more important than ability. Also, even though complex ideas are more beneficial for the population, individuals largely gain simple ideas during this phase—which was a surprise to the scientists.

“[T]he complexity of memes [ideas] present in the population does not increase but, on the contrary, decreases in time,” the scientists wrote in their study. “This happens as a result of intense competition among memes: whereas complex memes give advantage to individuals on a longer (biological) time scale, they lose competition to simpler memes on a shorter (social) time scale.”

After a while, though, the increasing brain becomes difficult to afford, partly due to high-risk births as well as energy consumption. Although accounting for only 2% of the body weight, the brain uses about 20% of a resting body’s metabolism. Therefore, cerebral expansion cannot last forever, and a “saturation phase” occurs, usually a couple hundred thousand generations later. Throughout this process, natural selection causes a competition between simple and complex ideas, where simple ideas always win because they spread easier. Other conditions that emerge in this phase promote postponing brain growth until after birth, and reducing the size of the guts.

 

[Jadis40]

Found this and thought it might be interesting:

http://www.messybeast.com/cat_talk.htm

HAVE CATS EVOLVED TO COMMUNICATE WITH HUMANS?
While not claiming that cats have acquired the power of human speech, in 2002, a Cornell University researcher investigated whether cats vocally manipulate their humans. Nicholas Nicastro, a graduate student working under psychology professor Michael Owren at Cornell University's Psychology of Voice and Sound Laboratory said that cats were obviously very dependent on people for their needs and that they may have evolved to become better at managing and manipulating people. While domestic cats may not know language, his study suggested that cats, which have lived alongside humans for thousands of years, have adapted their "meows" to better communicate with humans.


One way Nicastro attempted to prove his theory was by analysing a range of domestic cat vocalisations, playing these back to humans and then screening people's reactions to each type of sound. He did the same using the calls of wild cats in order to compare domestic cat and wild cat "speech". He recorded more than 100 different meows from 12 domestic cats (2 of them his own), soliciting various sounds from the cats by placing them in different situations (with their owners' help since cats rarely co-operate with strangers). These situations included delaying feeding time, before feeding them, putting them in empty rooms with the recorder, brushing them beyond the animals' patience for brushing and simply recording the contented meows of cats in a good mood.


I can attest from first hand experience that cats are definitely vocal, and sometimes their meows can sound like "words". Like my cat for example: usually "now", in reference to being fed, "no" when she doesn't want to be picked up and held etc...

 

[gluadys]

]I can attest from first hand experience that cats are definitely vocal, and sometimes their meows can sound like "words". Like my cat for example: usually "now", in reference to being fed, "no" when she doesn't want to be picked up and held etc...

Yep. Then there's the one that says "Open this door. I want to get in/out." And a very distinctive one that says "I've been successful in my hunt." --even if what she's caught is just a piece of kleenex.