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    What is the missing ingredient -- not genes, not upbringing -- that shapes the mind?
by   Steven Pinker

Genes account for about only about half of the variance in personality and intelligence. Environment doesn't fully account for the rest. As with Bob Dylan's Mister Jones, something is happening here but we don't know what it is, says Steven Pinker in a response to Edge publisher/editor John Brockman's request to futurists to pose "hard-edge" questions that "render visible the deeper meanings of our lives, redefine who and what we are."


Originally published January 2002 at Edge. Published on KurzweilAI.net January 21, 2002. Read Ray Kurzweil's Edge question here.

We know that genes play an important role in the shaping of our personality and intellects. Identical twins separated at birth (who share all their genes but not their environments) and tested as adults are strikingly similar-though far from identical-in their intellects and personalities. Identical twins reared together (who share all their genes and most of their environments) are much more similar than fraternal twins reared together (who share half their genes and most of their environments). Biological siblings (who share half their genes and most of their environments) are much more similar than adopted siblings (who share none of their genes and most of their environments).

Many people are so locked into the theory that the mind is a Blank Slate that when they hear these findings they say, "So you're saying it's all in the genes!" If genes have any effect at all, it must be total. But the data show that genes account for about only about half of the variance in personality and intelligence (25% to 75%, depending on how things are measured). That leaves around half the variance to be explained by something that is not genetic.

The next reaction is, "That means the other half of the variation must come from how we were brought up by our parents." Wrong again. Consider these findings. Identical twins separated at birth are not only similar; they are "no less" similar than identical twins reared together. The same is true of non-twin siblings -- they are no more similar when reared together than when reared apart. Identical twins reared together -- who share all their genes and most of their family environments-are only about 50% similar, not 100%. And adopted siblings are no more similar than two people plucked off the street at random. All this means that growing up in the same home -- with the same parents, books, TVs, guns, and so on -- does not make children similar.

So the variation in personality and intelligence breaks down roughly as follows: genes 50%, families 0%, something else 50%. As with Bob Dylan's Mister Jones, something is happening here but we don't know what it is.

Perhaps it is chance. While in the womb, the growth cone of an axon zigged rather than zagged, and the brain gels into a slightly different configuration. If so, it would have many implications that have not figured into our scientific or everyday way of thinking. One can imagine a developmental process in which millions of small chance events cancel one another out, leaving no difference in the end product. One can imagine a different process in which a chance event could derail development entirely, making a freak or monster. Neither of these happens. The development of organisms must use complex feedback loops rather than blueprints. Random events can divert the trajectory of growth, but the trajectories are confined within an envelope of functioning designs for the species defined by natural selection.

Also, what we are accustomed to thinking of as "the environment" -- namely the proportion of variance that is not genetic -- may have nothing to do with the environment. If the nongenetic variance is a product of chance events in brain assembly, yet another chunk of our personalities and intellects would be "biologically determined" (though not genetic) and beyond the scope of the best laid plans of parents and society.

Copyright © 2002 by Edge Foundation, Inc.



www.edge.org

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Who we are beyond nature vs. nurture
posted on 01/22/2002 7:52 AM by wendel

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Obviously, the attempt to limit explanations and definitions of who we are to only our own genes and nuture has not proven entirely satisfactory. I blieve that part of the reason is that we have elected thus far to ignore the host of microorganisms with DNA very similar to our own, including a few identical genes we share in common. I submit that such hosted microbes have natures and nurtures of thier own, independent from our own, to which they respond by expressing those self same genes. I am suggesting that a gene expressed for acetylcholine by some microbe we host, irrespective of the fact that acetylcholine may have a vastly different function in terms of that particular microbe's needs, makes no distinction between the acetylcholine cell binding sites of the microbe and our own.

As well, conceivably, there can be, and probably are, wars and competitions between our hosted micorbes, in which case our own sacred bods are mere war zones on some internacene microbe war. The "biochemical" consequences of such wars are certain to have an effect on the quantity of chemicals which bind to our own sacred cells, and therefore, to a degree, our "quality of life" as well as its quantity perhaps.

My bottom line suggestion: we, as human beings, are not merely the sum of our own nature and nurture, but are the sum of not only that but also
the sum of the microbes/micororganisms which we
invariably host at any one time. Know thy self? Hardly, rather know thy self in terms of all the contributors to that self, including the contribution made by passive or waring microbes.
In short, we are what we host ... or whatever microbes choose to make reservations in our very own genetic hotel.

If I were god, and I'm not a candidate for that office just now, I would not speak to any of my creation from burning bushes and such. After all, what language would I use exactly? Rather, I would wrap my message in a nice neat DNA or RNA universal language packet and trundle it off. I might even deliver it via some viral waystation or microbial UPS ... something on the order of how Bill Gates delivers software instructing computers how to crash more often and more efficiently. :-)

Re: Who we are beyond nature vs. nurture
posted on 06/02/2002 6:37 PM by jonikaranka@mixmail.com

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Mr Pinker seems to simplify "a little bit" the action that experience may have over the mind. Experience is not only the family and the school, even to the point that i would think that two of these brothers have a lot of experience in common: they will hear (nearly) the same language, see the same colors... and after all that low level experience they even may have more in common (not only genetics, which of course help a lot ;) ).

Re: What is the missing ingredient -- not genes, not upbringing -- that shapes the mind?
posted on 01/22/2002 1:27 PM by john.b.davey@btinternet.com

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I am glad to see the preposterously simplistic 'Genes' R ' Uz' biological theories seem to be on a much deserved wane.

Although we see with Pinker an influence of politics on science : even if he does acknowledge that genes are a far from clear cut influence on 'intelligence'. ( i've seen figures as low as 10% ), either way the polictcal opinion that some people aren't worth the effort still wins, I note - drawing social consclusions for a line of thought that he admits is pure speculation, a very dubious practice indeed although typical in a line of theory that spawned eugenics as a nasty sideline. Just when you thought we'd gort rid of our elites - phew ! says Pinker , you can relax now, they're still beyond help.

To suggest that 'Upbringing' merely invovles just arrangements in the family home is a bit silly - there is a massive world outside the family as well - and I remain dubious about the 'measuremenmts' of similarity - the notion that identical twins brought up in the same family aren't more similar than those who aren't would be a conclusion well woth wider checking.





It is the memes that shape the genocide, e.g. "intelligence" itself.
posted on 01/23/2002 6:57 AM by craighubleyus@yahoo.com

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It is the memes that shape the genocide itself that are the difference, e.g. theories of value that reward sociopaths breed more sociopaths. Result: the United States, Somalia, Taliban. Of these memes, the idea of "intelligence" itself is the most pernicious.

Re: What is the missing ingredient -- not genes, not upbringing -- that shapes the mind?
posted on 01/23/2002 4:03 PM by kwa@prospero.ch

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I agree (nearly) completely. Especially on the notion of similarity, which Pinker obviously measures in terms of variability.
It not only violates statistical principles, it is, if it is allowed to speak with L.Wittgenstein, free of any meaning (i.e. not wrong, it falls outside the category of correct or wrong)

Complex systems depend on the irreducible triadic relation between self (observer),the other (the observed), and the signal (sign) exchanged. This relation is the reason for strong differences in outcome for nearly identical starting points (theory of complex systems, edge of chaos, amplification of infinite small differences, etc.)

Asking about external reasons only is hopelessly reductionistic.

Klaus

Re: What is the missing ingredient -- not genes, not upbringing -- that shapes the mind?
posted on 02/17/2002 11:45 PM by hrathi@hotmail.com

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The unknown part that shapes our upbringing could well be not from this life. Although, it may depend on the karma we did in our past life!

Harish Rathi.

Re: What is the missing ingredient -- not genes, not upbringing -- that shapes the mind?
posted on 09/08/2002 12:10 PM by lottomagic@net2000.com.au

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Re: What is the missing ingredient -- not genes, not upbringing -- that shapes the mind?

Without having even read this piece, I will dare to answer your question. The answer is perception. You can have the same genes, the same upbringing and yet still perceive things differently. This can shape how you evolve as an individual.

For example take 2 identical twins who grow up in the same environment. So assume nature and nurture are basically the same, although in reality, there are subtle differences that can emerge over the evolution of each twin.

Also, identical twins may have different neurological development. One may have got more nutrients in the embryo etc.. bla bla.. so really nature and nurture are often only seen skin deep.

But assuming all was equal in both nature and nurture with 100% duplicity, then why does perception differ ? Well because perception is often based on incomplete information. Sometimes based on mere chance either in terms of nature or nurture.

Even though two twins may share exactly the same genetic blue print to the nth degree, the subtle forces of nature could effect the individual experience at the most elemental level. From here the effect can be compounding as each individual evolves and the effects of their perceptions are also compounded and hence their judgements and actions. Some outcomes result in better survival opportunities than others and hence better evolution opportunities.

Anyway that's my view, until I get another view.

Regards,
Dave
9 Sep 2002

PS
How do I know this to be true you may well ask? Well I spoke to some Aliens who told me it was true. I guess I believed them, as they seemed smarter than me. But they were nice Aliens. They even offered me a cup of tea and scones.


Re: What is the missing ingredient --cup of tea and scones
posted on 09/09/2002 8:19 PM by claire@cthisspace.com

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Dave says it,

That's the key to AI, the onswers simple:


Cup of tea and scones.


Give an AI being a cuppa and scone test and forget Turing. If it can feel the temerature of the tea and taste the Scone, its nearer to I that A. Kurzweil, are you listening?

Claire, www.cthisspace.com

Re: What is the missing ingredient --cup of tea and scones
posted on 09/09/2002 11:12 PM by lottomagic@net2000.com.au

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I guess I should add that perception and experience will probably be more applicable to nurture, where as experience alone or cause and effect, may be more predominately associated with nature.

For example, in embryonic states, perception is extremely limited, if at all existent. However the effects of the biological forces on two cloned embryos can be at variance within the human body. This alone could be sufficient to trigger the cumulative effect I mentioned in terms of their hence ongoing development, evolution and further transmission of their genes to offspring. A bit like the KAOS effect. Or something like two barns in a tornado, one gets damaged, and one gets spared the effects.

The damaged one may have been occupied at the time and someone may have been hurt or even killed. This person may have gone on to make an amazing discovery, never to be discovered. Or vice versa with the person being in the standing barn un hurt and allowed to continue their path to that discovery that changed the world and effecting the evolution of man. Yea I'm getting a bit off the track I know. I better stop now.


Dave lotto wizard
www.lottomagic.com
10 Sep 2002



Re: What is the missing ingredient --cup of tea and scones
posted on 09/09/2002 11:59 PM by azb0@earthlink.net

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Dave,

Your point is well taken (especially the "Chaos effect"), and it (the nature/nuture debate) demonstrates to me another example of how we try to impose our clean conceptual logic on the universe, and it fights back.

Certainly the "genetics end" of the stick plays a large part in what we become, and the "socializing end" plays its part as well. We tend to divide these influences into "what we cannot change" (nature) and "what we can change" (nurture). But these seemingly sharp distinctions break down upon closer inspection.

If a mother bearing "identical" twins takes a particular medication (or one too many cups of tea with scones;), it might affect one fetus and not the other. Is this "nature or nurture"? Perhaps one fetus is positioned in the womb in a less agreeable posture. Again, nature or nurture?

Cheers! ____tony b____

Re: What is the missing ingredient --cup of tea and scones
posted on 09/10/2002 3:01 AM by lottomagic@net2000.com.au

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Tony, Yes I agree it raises a very interesting question, which you have highlighted even further.

cheers,
David

Re: What is the missing ingredient --cup of tea and scones
posted on 09/10/2002 3:16 AM by lottomagic@net2000.com.au

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I do tend to forget about Turing as I think the concept is antiquated and irrelevant. Sorry to sound controversial. But I think his test is inappropriate and overly simplistic for it to reasonably measure AI or the effectiveness of AI.

I mean a real smart AI bot could fool a kid into thinking it was talking to a human. Now these bots are just bots really aren't they? I mean nobody could seriously suggest that they could lay claim to intelligence as we know it. Even SmarterChild AI bot just rattles of a string sequence of standard responses to questions.

Re: What is the missing ingredient --cup of tea and scones
posted on 09/10/2002 4:57 AM by azb0@earthlink.net

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Dave,

The "Turing Test" was formulated long ago, and although it might well be improved upon, If you *really* think about it, it can be a good test for intelligence if you make it so.

Canned responses will get old rather quickly, and even with a huge store of minor variations, it is more the "appropriateness" of the response that counts.

If we stick to "text responses only", suppose you and I are having a "live chat", and in the middle of a response about global warming, I "interrupt myself" to say, "Uh-Oh, the gf is home from work." If you were the AI, you would need to:

a) Know "gf" meant "girlfriend".

b) Understand that "home from work" means she is now present at my locale (else, how would I know she was home? Perhaps I just read about it in the newspaper?)

c) Understand that my "Uh-Oh" implies that I might get in trouble for being on the computer. Why would this seem "natural" to you, unless you somehow understood that spouses can sometimes be "touchy" about sharing time with others, espacially via the "great anonymous internet".

d) Remember if I had previously said something like, "I share a house with Sally, and she is at work" (whatever "work" is), and then surmise that I was talking about the same person.

So ... a "canned" (or even poorly generated and customized), yet simplistic response like, "Does it trouble you that your girlfriend is home from work?" would seem stiff and unnatural, whereas "Oh, I know how that can be - I better let you go for now", would seem far more human and "understanding".

I could have also made the conversation a bit more "analytically difficult". I might have said, "I share a house with Sally, but she's off balancing the books for a customer this afternoon." And then, later on, I could have said "Uh-Oh, the little accountant is pulling up in the driveway."

Then you would have to properly link "balancing books" with "accounting" (as opposed to balancing them on you head as a posture enforcing exercise) as well as understand that "pulling up in the driveway" means "has arrived at home, where I reside", as well as be sensitive to the other appropriate "human" understandings about feelings and pet-peeves, etc.

Overall, that is an ENORMOUS amount of intelligence you would have to draw upon, in rapid responses, and not "slip up" and say something that would make almost no sense at all.

For a machine to pass a good strong Turing Test, it would need both a huge breadth of "common knowledge", as well as understand the relations between things, subtle nuances of my phraseology that hinted whether I was being sarcastic or humourous or genuine in a particular response, etc.

In 10 years (with a dedicated research-level machine) we may come close to this. In 20 years, I am quite sure it could fool the best of us.

By then, speech synthesis should be advanced to the point that the AI could formulate "natural speech", along with delicate intonements (to indicate that IT was intending sarcasm or humor), and even slurring or "stumbling" over words when it gets into an excited exchange, and try to talk too fast, or interrupt itself in mid-sentence, etc.

Imagine a Turing Test that you could have over the phone.

Of course, it would (likely) not be "feeling" any of the "emotions it was emoting", might not really feel amused or annoyed or excited, but rather "calculate" that this would be the appropriate response at the given moment in order to appear "human-like". So it could be exceedingly "intelligent", and not at all a "sentient being" (as we experinece being sentient and "awake").

That (sentience) might require more that programming and arbitrarily conducted formal calculation. It might actually (I suspect) be a function of how those processes are manifest in a physical substrate.

Cheers! ____tony b____

Re: What is the missing ingredient --cup of tea and scones
posted on 11/17/2002 9:06 PM by Dave

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I agree that Turing seems overly simplistic in its attempt to determine true or useful artificial intelligence. The problems with Turing is that it does not show cause and effect in terms of understanding. It just seems to show association. i.e. association of what appears to be a correct or meaningful response to a given question. I'm not convinced that this is sufficient enough for us to feel confident about the Turning test.

Clueless Pinker
posted on 04/18/2003 11:58 PM by Clifford

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Pinker's a stumblebum.

He just spent 30 minutes explaining to the Congressional waxworks that designer babies are a pipedream.

Well, thank God we dodged THAT bullet, Steve, but if you'd ever gone down to the student union news stand and picked up a copy of "MIT's Technology Review", you'd know that the topic at hand is BRAIN-MACHINE INTERFACE.
For two years they've had computer chips installed in the brains of monkeys so they can control robotic arms. Next month they're going to install a brain prosthesis into rats and The Economist magazine ran a cover story called, "The Future of Mind Control".

So take "GATTACA" back to the video store and get a haircut, pal.

Re: What is the missing ingredient -- not genes, not upbringing -- that shapes the mind?
posted on 04/19/2003 1:24 AM by Courtney

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Purpose.

Re: What is the missing ingredient -- not genes, not upbringing -- that shapes the mind?
posted on 12/03/2004 12:34 PM by pauladams

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Random events yes, but more likely those random events were in the experiences (i.e. the outside world) of the individual twins, not in growth cone accidents in their brains.

Re: What is the missing ingredient -- not genes, not upbringing -- that shapes the mind?
posted on 12/06/2005 10:25 PM by simpleprogram

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Personality :-

Environmental personality development may be there but beyond the control of most parents. The environment is still affecting it, but left to do so from outside and chance influences that all children are exposed to equally. It seems strange however that parents have no effect on personality as Pinker seems to be saying. As we all know that parents that are way too strict with their kids often create a rebel, which is clearly a personality trait. And here with the example of rebel lies another argument. Maybe, the two cancel each other out. I.e. the rebel is likely to do not what the parents say - but the opposite. So if you had an equal number of rebels and none rebels: then both of them would cancel each other out and the average effect recorded would make it appear that the parents were having no effect. They are, it is just that some of them are creating children the opposite of how they set out. Or so the idea goes' What this does show is how complex the interactions of nature via. nurture are. It is easy to miss something, as Pinker could have here.

Intelligence (IQ level):-

Most adopted children in the samples go to a selection of reasonably well off parents. SES is thought to influence intelligence development, with several studies in different countries proving the effect is very strong at lowering intelligence when SES goes below a certain threshold. That accounts for environment. But it is not picked up in Pinker's data as most go to resonably well off familes. At higher levels of SES, genes are the primary influence. So it's all down to them having the same environment after all. Just because the twins sampled go to other parents does not automatically mean that the other parents will be a fair random sample; a simple mistake, as it seems a better understanding of what it going on would have solved it for him.