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Why haven't other organisms evolved humanlike intelligence?

by Jupiter60
Tags: evolved, humanlike, intelligence, organisms
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Pythagorean
#37
Sep8-14, 04:26 PM
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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/2004/0403...s040322-9.html
Acid92
#38
Sep8-14, 04:31 PM
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"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/sc...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
#39
Sep8-14, 05:24 PM
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Quote Quote by DiracPool View Post
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.

Quote Quote by DiracPool View Post
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.

Quote Quote by DiracPool View Post
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
#40
Sep8-14, 06:20 PM
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Quote Quote by Doofy View Post
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
#41
Sep8-14, 09:27 PM
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Quote Quote by Doofy View Post
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
#42
Sep9-14, 11:43 AM
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Quote Quote by DiracPool View Post
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.

Quote Quote by DiracPool View Post
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?

Quote Quote by DiracPool View Post
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.

Quote Quote by DiracPool View Post
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
#43
Sep12-14, 10:50 PM
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Quote Quote by Doofy View Post
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;

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.


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