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Is human intelligence “close to its evolutionary limit”?

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1950s sci fi "Attack of the Brain Monster" figurine gives a sense of the pop culture view. (For price and availability, click the image.)

At Scientific American, Douglas Fox reports on “The Limits of Intelligence,” where  we learn that “The laws of physics may well prevent the human brain from evolving into an ever more powerful thinking machine” (June 14, 2011):


Human intelligence may be close to its evolutionary limit. Various lines of research suggest that most of the tweaks that could make us smarter would hit limits set by the laws of physics.

Brain size, for instance, helps up to a point but carries diminishing returns: brains become energy-hungry and slow. Better “wiring” across the brain also would consume energy and take up a disproportionate amount of space.

Making wires thinner would hit thermodynamic limitations similar to those that affect transistors in computer chips: communication would get noisy.

Humans, however, might still achieve higher intelligence collectively. And technology, from writing to the Internet, enables us to expand our mind outside the confines of our body.

Interestingly, popular culture has always regarded the idea of a really big brain with suspicion; the usual tale is that the Big Brain requires monstrous problems to solve, and thus creates them.

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Question: Some people think we can and will boost intelligence. Do these groups talk to each other? Thoughts?

Fitness landscapes are extremely high dimensioned!
Are those the things that have the armadillo-shaped niches and the owl-shaped niches and the sea-urchin shaped niches? Sorry for being so facetious. I just find it amusing when something so completely hypothetical and nebulous, nothing more than a reflection of what it purports to explain, is described as a 'multi-dimensioned fitness landscape.' One could get the impression that such a concept explains something about the natural world that wasn't previously known. Sorry, that is a little snarky, and I don't really mean to be. ScottAndrews
Right now, the strongest selective pressures on human beings, though, are probably presented by our very recently acquired control over our own fertility.
I agree that those who use contraception correctly are less likely to reproduce. But what does that select for? Is there a gene for not using contraception? Or for not being able to use it correctly? When it becomes fixed will we become a species incapable of reading and applying small-print instructions on packages? Considering the vast array of behaviors, both human and animal, that we attribute to such selective pressures, we must also seriously entertain scenarios such as the above. If such deliberate, widespread selection cannot have such an impact, how can slow, nuanced selection have any at all? It has only had a few billion years to work with. ScottAndrews
Fitness landscapes are extremely high dimensioned!
How then do we model them? Mung
ScottAndrews: As a "Darwinist", obviously I'd say that the brain always has and always will "obey the laws of physics"! Where I think the claim cited in the OP is silly is that it assumes that there is a single (physical) dimension along which intelligence can increase. Intelligence is multidimensional anyway, and, in any case, the brain is full of alternative pathways in which transmission happens at different speeds, and the range of speeds is partly what underlies some aspects of what we call intelligence. For instance, in perception, there is a fast "where is it?" pathway and a slowler "what is it?" pathway, and the two have to work together (the "where is it?" pathway directs the data flow to the "what is it?" pathway, for instance). And there are also rapid "emergency" pathways that seem to bypass higher functions anyway, and clearly these are important to survival. "Blindsight" is an example of where the fastest "emergency" visual pathway is preserved, but the "where" and "what" cortical pathways are disrupted. As for "future evolution" - well, evolution follows what increases the number of viable offspring we leave! Greater "intelligence" along various dimensions may, or may not, do that, in our current environment. If not, then, our brains won't evolve along those diminsions. If yes, then, if those dimensions have further room for growth, then, possibly. In which case, in the very limited dimension pointed out by the physicists, we may indeed have reached our limit. That doesn't mean we can't (if it proves a selective advantage) evolve to become more intelligent, it just means that we won't do it along that dimension. Fitness landscapes are extremely high dimensioned! Right now, the strongest selective pressures on human beings, though, are probably presented by our very recently acquired control over our own fertility. Elizabeth Liddle
I find it curious that someone would dismiss the unlikeliness of the all of the years of previous speculated evolution, but then say that future evolution is now very unlikely. We can't deny reason when explaining the origin of the brain up to this point and then suggest that from this moment on it must obey the laws of physics. Perhaps the brain will evolve to utilize a multiverse for continued growth and energy. ScottAndrews
There is no consensus on how to define "intelligence." It seems a bit premature to make declarations as to whether there is a limit and whether we have reached that limit. Neil Rickert
A favorite quote from Calvin Coolidge: Nothing in this world can take the place of persistence. Talent will not; nothing is more common than unsuccessful people with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. ScottAndrews
That's interesting, thanks :) Of course we have to remember that all IQ tests do is measure something that correlates reasonably well with academic success. So it would be interesting to know that in countries that have maxed out the Flynn effect, that correlation remains as strong. If so, the raised raw scores may indicate useful additional skill; if not, it may just reflect more practice opportunities for IQ test questions :) Interestingly, IQ scores are not an especially good predictor of "giftedness" at least if "giftedness" is identified retrospectively on the basis of achievement. IQ tests have never been very good at measuring creativity, which is obviously pretty important when it comes to the kind of giftedness makes people a byword for brilliance. I read a study a while ago that examined the IQ of people generally regarded as "gifted" adults - people who had made a marked impact on their domain, and although mean IQs were high, they weren't astronomical. I think they were all over 125. After that, something else seems to be just as important as more IQ points :) (I suspect that's not true of mathematicians though - my hunch is that whatever it is that mathematicians have, is the same kind of stuff that scores on IQ tests). [/ramble] Cheers Lizzie Elizabeth Liddle
Elizabeth Liddle: Thank you for your post. It may interest you to know that in some countries at least, IQ scores have stopped drifting upwards. The Flynn effect seems to be coming to a close in Scandinavia, and perhaps other countries too: http://www.timesonline.co.uk/tol/news/uk/article756647.ece http://www.iapsych.com/iqmr/fe/LinkedDocuments/Sundet2004.pdf http://en.wikipedia.org/wiki/Flynn_effect#Possible_end_of_progression vjtorley
However, given the huge impact of the environment on intelligence, we will probably get smarter anyway. Raw IQ scores are constantly drifting upwards. Elizabeth Liddle
Well, speed-of-processing is only one aspect of intelligence. On the full Wechsler scales, other factors are: Verbal; "Performance" (non verbal tasks like matrix reasoning); speed of processing; working memory. And creativity tends to get left out of IQ measures. Working memory is pretty useful, and is probably a function of the efficiency with which circuits are switched off as much as efficiency with which they are switched on. As far as evolution is concerned though, the issue is whether an increase in any of these things result in an increased number of viable offspring :) Not necessarily. Elizabeth Liddle
I'm not sure I'd want a brain wired together by accident. Mung

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