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mouse
Joined: 10 Jul 2006
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 Posted: Wed May 07, 2008 7:20 pm Post subject: science news: this could explain a lot |
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seems that intelligence comes at a cost (it's a bit long, so this is just some highlights)
| Quote: | May 6, 2008
Lots of Animals Learn, but Smarter Isn’t Better
By CARL ZIMMER
“Why are humans so smart?” is a question that fascinates scientists. Tadeusz Kawecki, an evolutionary biologist at the University of Fribourg, likes to turn around the question.
“If it’s so great to be smart,” Dr. Kawecki asks, “why have most animals remained dumb?”
Dr. Kawecki and like-minded scientists are trying to figure out why animals learn and why some have evolved to be better at learning than others. One reason for the difference, their research finds, is that being smart can be bad for an animal’s health.
Learning is remarkably widespread in the animal kingdom. Even the microscopic vinegar worm, Caenorhabditis elegans, can learn, despite having just 302 neurons. It feeds on bacteria. But if it eats a disease-causing strain, it can become sick.
The worms are not born with an innate aversion to the dangerous bacteria. They need time to learn to tell the difference and avoid becoming sick.
Many insects are also good at learning. “People thought insects were little robots doing everything by instinct,” said Reuven Dukas, a biologist at McMaster University.
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Learning also turns out to have dangerous side effects that make its evolution even more puzzling. Dr. Kawecki and his colleagues have produced striking evidence for these side effects by studying flies as they evolve into better learners in the lab.
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It takes just 15 generations under these conditions for the flies to become genetically programmed to learn better. At the beginning of the experiment, the flies take many hours to learn the difference between the normal and quinine-spiked jellies. The fast-learning strain of flies needs less than an hour.
But the flies pay a price for fast learning. Dr. Kawecki and his colleagues pitted smart fly larvae against a different strain of flies, mixing the insects and giving them a meager supply of yeast to see who would survive. The scientists then ran the same experiment, but with the ordinary relatives of the smart flies competing against the new strain. About half the smart flies survived; 80 percent of the ordinary flies did.
Reversing the experiment showed that being smart does not ensure survival. “We took some population of flies and kept them over 30 generations on really poor food so they adapted so they could develop better on it,” Dr. Kawecki said. “And then we asked what happened to the learning ability. It went down.”
The ability to learn does not just harm the flies in their youth, though. In a paper to be published in the journal Evolution, Dr. Kawecki and his colleagues report that their fast-learning flies live on average 15 percent shorter lives than flies that had not experienced selection on the quinine-spiked jelly. Flies that have undergone selection for long life were up to 40 percent worse at learning than ordinary flies.
“We don’t know what the mechanism of this is,” Dr. Kawecki said.
One clue comes from another experiment, in which he and his colleagues found that the very act of learning takes a toll. The scientists trained some fast-learning flies to associate an odor with powerful vibrations. “These flies died about 20 percent faster than flies with the same genes, but which were not forced to learn,” he said.
Forming neuron connections may cause harmful side effects. It is also possible that genes that allow learning to develop faster and last longer may cause other changes.
“We use computers with memory that’s almost free, but biological information is costly,” Dr. Dukas said. He added that the costs Dr. Kawecki documented were not smart animals’ only penalties. “It means you start out in life being inexperienced,” Dr. Dukas said.
When birds leave the nest, they need time to learn to find food and avoid predators. As a result, they are more likely to starve or be killed.
Dr. Dukas argues that learning evolves to higher levels only when it is a better way to respond to the environment than relying on automatic responses.
“It’s good when you want to rely on information that’s unique to a time and place,” Dr. Dukas said. Some bee species, for example, feed on a single flower species. They can find plenty of nectar using automatic cues. Other bees are adapted to many different flowers, each with a different shape and a different flowering time. Learning may be a better strategy in such cases.
Scientists have carried out few studies to test this idea. One study, published this year by scientists at the University of London, showed that fast-learning colonies of bumblebees collected up to 40 percent more nectar than slower colonies.
Dr. Kawecki suspects that each species evolves until it reaches an equilibrium between the costs and benefits of learning. His experiments demonstrate that flies have the genetic potential to become significantly smarter in the wild. But only under his lab conditions does evolution actually move in that direction. In nature, any improvement in learning would cost too much.
Dr. Kawecki and Dr. Dukas agree that scientists need to pinpoint the tradeoffs, and they will have to gauge the role of learning in the lives of many species. As their own knowledge increases, they will understand more about humans’ gift for learning.
“Humans have gone to the extreme,” said Dr. Dukas, both in the ability of our species to learn and in the cost for that ability.
Humans’ oversize brains require 20 percent of all the calories burned at rest. A newborn’s brain is so big that it can create serious risks for mother and child at birth. Yet newborns know so little that they are entirely helpless. It takes many years for humans to learn enough to live on their own.
Dr. Kawecki says it is worth investigating whether humans also pay hidden costs for extreme learning. “We could speculate that some diseases are a byproduct of intelligence,” he said.
The benefits of learning must have been enormous for evolution to have overcome those costs, Dr. Kawecki argues. For many animals, learning mainly offers a benefit in finding food or a mate. But humans also live in complex societies where learning has benefits, as well.
“If you’re using your intelligence to outsmart your group, then there’s an arms race,” Dr. Kawecki said. “So there’s no absolute optimal level. You just have to be smarter than the others.” |
i actually got to the article from an opinion piece, which i rather liked:
| Quote: | May 7, 2008
Editorial Notebook
The Cost of Smarts
By VERLYN KLINKENBORG
Research on animal intelligence always makes me wonder just how smart humans are. Consider the fruit-fly experiments described in Carl Zimmer’s piece in the Science Times on Tuesday. Fruit flies who were taught to be smarter than the average fruit fly tended to live shorter lives. This suggests that dimmer bulbs burn longer, that there is an advantage in not being too terrifically bright.
Intelligence, it turns out, is a high-priced option. It takes more upkeep, burns more fuel and is slow off the starting line because it depends on learning — a gradual process — instead of instinct. Plenty of other species are able to learn, and one of the things they’ve apparently learned is when to stop.
Is there an adaptive value to limited intelligence? That’s the question behind this new research. I like it. Instead of casting a wistful glance backward at all the species we’ve left in the dust I.Q.-wise, it implicitly asks what the real costs of our own intelligence might be. This is on the mind of every animal I’ve ever met.
Every chicken that looks at you sideways — which is how they all look at you — is really saying what Thoreau said less succinctly: you are endeavoring to solve the problem of a livelihood by a formula more complicated than the problem itself. Thoreau himself would not dispute that he was hoping to recover the chicken’s point of view. He went to Walden Pond “to remember well his ignorance.”
Research on animal intelligence also makes me wonder what experiments animals would perform on humans if they had the chance. Every cat with an owner, for instance, is running a small-scale study in operant conditioning. I believe that if animals ran the labs, they would test us to determine the limits of our patience, our faithfulness, our memory for terrain. They would try to decide what intelligence in humans is really for, not merely how much of it there is. Above all, they would hope to study a fundamental question: Are humans actually aware of the world they live in? So far the results are inconclusive. VERLYN KLINKENBORG |
i'm tempted to relate all this to voting patterns, but i will restrain myself.
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Sam the Eagle
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| Posted: Thu May 08, 2008 9:50 am Post subject: |
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Einstein quote of the day :
"Two things are infinite: the universe and human stupidity. I'm still not sure about the the universe."
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Pontupo
Joined: 07 Mar 2008
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| Posted: Thu May 08, 2008 1:45 pm Post subject: |
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| I've thought for some time that the aware (in contrast, perhaps, with the intelligent) have a harder time of it. While I'm sure there are some benefits to knowledge and understanding... wisdom, the cost is that you do actually know what's going on, and the news may not be all that positive. They do say that ignorance is bliss, after all. |
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Dragonwriter
Joined: 08 Sep 2007
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| Posted: Thu May 08, 2008 3:50 pm Post subject: |
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Interesting perspective... I shall have to THINK on it for a while...
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Thy Brilliance
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| Posted: Fri May 09, 2008 9:27 am Post subject: No one sees the irony in the dumbed-down article? |
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| Heh, evolutionary philosophy. |
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Mizike
Joined: 09 Jul 2006
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| Posted: Fri May 09, 2008 11:24 am Post subject: |
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The article was actually really well written and made me think back to the only athropology-like (as opposed to anthropological) class I ever took. Neanderthals were smarter than humans according to how we generally measure the intelligence of animals (ratio of brain cavity to body size).
It's also a really nice example how every mutation and evolutionary change can have both pros and cons.
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"It is laudable to know something, it is disgraceful to not want to learn"
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Pontupo
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| Posted: Fri May 09, 2008 12:58 pm Post subject: |
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| It's interesting that one would measure the relative intelligence of species by the ratio of brain cavity to body size when variability in brain cavity to body size within species has been clearly shown to bear no relationship to intelligence (i.e. people with big heads are not necessarily smarter). |
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WheelsOfConfusion
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| Posted: Fri May 09, 2008 3:00 pm Post subject: |
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| Mizike wrote: | | The article was actually really well written and made me think back to the only athropology-like (as opposed to anthropological) class I ever took. Neanderthals were smarter than humans according to how we generally measure the intelligence of animals (ratio of brain cavity to body size). |
Not according to this. Neanderthals had completely disappered in Europe by 30,00 ya. This table of estimated body mass and brain sizes shows that before the total disappearance of non-modern hominids, EQ did not rise above 5 (excepting the Skhul-Qafzeh specimen, which is an archaic sapiens). This study more specifically places Neanderthals bellow modern humans in terms of EQ, although compared to the first link it gives a much higher EQ to modern humans.
While they may have had slightly larger brain cavities, they also had much more robust and stocky bodies, pumping up the body mass end of the equation, and their brains were slightly smaller in both relative and absolute terms. It was a very close comparison, though.
| Pontupo wrote: | | It's interesting that one would measure the relative intelligence of species by the ratio of brain cavity to body size when variability in brain cavity to body size within species has been clearly shown to bear no relationship to intelligence (i.e. people with big heads are not necessarily smarter). |
But in modern humans those differences are relatively tiny, and furthermore all modern humans belong to the same species (which is genetically pretty uniform compared even to our less populous close relatives) and so would have more similar brains than two different species of humans.
When looking among different species, there does seem to be a rough correlation between encephalization quotient (brain/body size) and observed intelligence, especially if body fat is removed from the picture.
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Mizike
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| Posted: Fri May 09, 2008 5:26 pm Post subject: |
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| WheelsOfConfusion wrote: | | Mizike wrote: | | The article was actually really well written and made me think back to the only athropology-like (as opposed to anthropological) class I ever took. Neanderthals were smarter than humans according to how we generally measure the intelligence of animals (ratio of brain cavity to body size). |
Not according to this. |
Well, the professor was from Northern Ireland, so he could have been wrong.
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"It is laudable to know something, it is disgraceful to not want to learn"
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Pontupo
Joined: 07 Mar 2008
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| Posted: Fri May 09, 2008 5:44 pm Post subject: |
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| WheelsOfConfusion wrote: |
| Pontupo wrote: | | It's interesting that one would measure the relative intelligence of species by the ratio of brain cavity to body size when variability in brain cavity to body size within species has been clearly shown to bear no relationship to intelligence (i.e. people with big heads are not necessarily smarter). |
But in modern humans those differences are relatively tiny, and furthermore all modern humans belong to the same species (which is genetically pretty uniform compared even to our less populous close relatives) and so would have more similar brains than two different species of humans.
When looking among different species, there does seem to be a rough correlation between encephalization quotient (brain/body size) and observed intelligence, especially if body fat is removed from the picture. |
I see what you're saying about the degree of the variability. What precedent is there for different patterns between species vs. between members of the same species? I want to conceive of this kind of pattern as being a general pattern, which would suggest that you can apply it to members within a species (even if the variance is much smaller). I'd just like to know why a pattern would apply to differences between species while not applying within, both empirically and rationally (i.e. we've seen this is true and this is why). I imagine it may be difficult to get statistically significant results when the degree of variance is so small...
The only references I've ever heard to intelligence being unrelated to brain size were specifically concerned with the absolute size of the brain. Have studies been done concerning EQ and intelligence in humans?
EDIT: I see that EQ is specifically the volume of the brain of the subject in question divided by the brain volume of a "standard" comparison animal corrected for body mass, so I guess my question doesn't really make sense. So EQ only means something between species by definition? In any case, I'd like to see a study of intelligence relative to brain volume divided by body mass between human subjects. |
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WheelsOfConfusion
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| Posted: Fri May 09, 2008 6:19 pm Post subject: |
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Within a species, you have basically all the same genes controlling the development of the brain in pretty much the same way. In different species, which parts of the brain develop in which way can be different according to the species. Since two different species diverge genetically, you can expect that the genes responsible for making brains can be slightly different, with one group having mutations not shared with the other.
For example, what if Neanderthal brains were able to analyze smells slightly better? We might expect that the parts of the brain responsible for olfactory processing might be more developed and to develop sooner compared to the brains of modern humans. How much of the brain is devoted to driving and coordinating the larger, denser muscles of Neanderthals compared to sapiens? At the time modern humans developed, they lived exclusively in Africa: Neanderthals had moved into Europe and Asia and adapted to the generally colder climates of those areas and therefore different environmental challenges. Although the two species were very closely related, we can expect some significant differences in the structure of their respective brains.
If you look at domestic dogs and their wild forebearers, gray wolves, you see that in general the wolves have a somewhat larger cranial capacity than dogs of the same size. This despite the fact that gray wolves and domestic dogs are only as separated by time as humans and our closest relatives, at most. It shows that even closely related species (in fact they are so closely related that the usual definition of species, the inability for the two to breed fertile offspring, doesn't apply) can have significantly different brain structures.
However, comparing dogs to dogs, you can have an English bulldog and a border collie and see that the one with the bigger brain/body ratio isn't always smarter.
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nathan
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| Posted: Sun May 11, 2008 6:43 am Post subject: |
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| Pontupo wrote: | | I've thought for some time that the aware (in contrast, perhaps, with the intelligent) have a harder time of it. While I'm sure there are some benefits to knowledge and understanding... wisdom, the cost is that you do actually know what's going on, and the news may not be all that positive. |
Can't help but wonder how much it may have to do with understanding complex systems and choice theory. On the one hand, a person's degree of willful/intentional influence over their surroundings would likely drop (both subjectively and objectively) as the relationships describing the state of those surroundings become increasingly complex, and on the other hand each new potential action made available by a more nuanced understanding of the world makes it less likely we'll be happy with the action we ultimately choose. So broadly speaking, as a feller gets wiser he feels less and less in control of his own life, and grows more and more uncertain about the decisions over which he DID exert control.
Unrelated to the article, of course.
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YenTheFirst
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| Posted: Sun May 11, 2008 7:00 am Post subject: |
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if such extreme intelligence, and the mutation path leading there, is so un-advantageous..why would animals with such an emphasis on intelligence as humans ever evolve?
clearly, the only answer is intelligent design.
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WheelsOfConfusion
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| Posted: Sun May 11, 2008 2:31 pm Post subject: |
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| nathan wrote: | | Pontupo wrote: | | I've thought for some time that the aware (in contrast, perhaps, with the intelligent) have a harder time of it. While I'm sure there are some benefits to knowledge and understanding... wisdom, the cost is that you do actually know what's going on, and the news may not be all that positive. |
Can't help but wonder how much it may have to do with understanding complex systems and choice theory. On the one hand, a person's degree of willful/intentional influence over their surroundings would likely drop (both subjectively and objectively) as the relationships describing the state of those surroundings become increasingly complex, and on the other hand each new potential action made available by a more nuanced understanding of the world makes it less likely we'll be happy with the action we ultimately choose. So broadly speaking, as a feller gets wiser he feels less and less in control of his own life, and grows more and more uncertain about the decisions over which he DID exert control.
Unrelated to the article, of course. |
So what you're saying is that the more you know, the more you know that you don't know much, and that the wise man knows he doesn't know anything?
PFFFT! C'mon, who'd ever buy into that crap?
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Ibian
Joined: 30 Mar 2008
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| Posted: Sun May 11, 2008 3:02 pm Post subject: |
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Certainly not the biggest arguer, obviously.
Which doesnt change that people who are very sure of themselves are usually not very bright. |
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