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AIList Digest Volume 7 Issue 012
AIList Digest Thursday, 2 Jun 1988 Volume 7 : Issue 12
Today's Topics:
Twin Studies
Philosophy
Symbolics stock
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Date: 16 May 88 03:59:48 GMT
From: quintus!ok@sun.com (Richard A. O'Keefe)
Subject: Re: AIList V6 #86 - Philosophy
In article <523@wsccs.UUCP>, dharvey@wsccs.UUCP (David Harvey) writes:
> lives. Even a casual perusal of the studies of identical twins
> separated at birth will produce an uncanny amount of similarities, and
> this also includes IQ levels, even when the social environments are
> radically different.
ONLY a casual perusal of the studies of separated twins will have this
effect. There is a selection effect: only those twins are studied who
are sufficiently far from separation to be located! A lot of these
so-called "separated" twins have lived in the same towns, gone to the
same schools, ...
------------------------------
Date: 20 May 88 09:00:08 GMT
From: mcvax!ukc!strath-cs!glasgow!gilbert@uunet.uu.net (Gilbert
Cockton)
Subject: Twin Studies: Problems of Confounding Variables and Sample
Populations
In article <2865@cvl.umd.edu> harwood@cvl.UUCP (David Harwood) writes:
> Can you substantially prove that there is not sound research
>which shows comparatively significant psychological similarity of
>identical twins, even when growing up apart?
To start, yes there are similarities. The results weren't being
questioned, it was the interpretation, and the original 'experimental'
design. These are the two major weak links in psychological research,
and for that matter in mathematical modelling (e.g. sociobiological
applications of game theory).
On experimental design, there is a problem in assuming that any population
of separated identical twins share all the variation likely in the
full population. The role of adoption agencies is particularly
important, as they all have ideals of parenthood which many social
groups will not be able to fulfil. Hence the separated identical twins
will be less environmentally separated than the Bronx and the Berkshires.
Another problem in experimental design is the very measure of
'radically different environments'. The twin studies cannot rely on
assuming that ANY difference in environment could be relevant to
development; the relationship has to be established by separate research.
It largely because of the uncritical approach to social environments
that any interpretations of 'results' will be invalid. If you don't
control for confounding factors, your results aren't worth the paper
they're printed on.
I have no published work here either, but had to write on the topic as
part of my Education degree. All the above is so obvious in
psychology that it wouldn't be worth publishing, except within a more
thorough review article. I've bothered to post this to
a) defend Richard's argument
b) improve some people's awareness of experimental design
and thus hopefully encourage more constructive criticism
and less credulity about BIG twin studies.
Apologies to anyone who wants this sort of stuff out of comp.ai, but
if you are interested in computer simulation of human behaviour, I
don't see how you can justify the exclusion of anything to do with the
study of humanity from this group.
--
Gilbert Cockton, Department of Computing Science, The University, Glasgow
gilbert@uk.ac.glasgow.cs <europe>!ukc!glasgow!gilbert
The proper object of the study of humanity is humans, not machines
------------------------------
Date: 20 May 88 21:35:25 GMT
From: wlieberm@teknowledge-vaxc.arpa (William Lieberman)
Subject: Re: Twin studies (was AIList V6 #86 - Philosophy)
In article <8805201729.AA28919@decwrl.dec.com> cooper@pbsvax.dec.com writes:
>> <<Richard O'Keefe claiming that studies of separated identical twins being
>> invalid because of a tendency for their environments to continue to
>> be the same.>>
>
>I can't say that I am overly familiar with this area, but all the "separated
>twin" studies which I have seen discussed as evidential (rather than merely
>suggestive of further research) have seemingly controlled for this by
>comparing the variance of the characteristic under study in identical
>twins separated at birth (100% genetic similarity) against fraternal
>twins separated at birth (50% genetic similarity). Is there a significant
>body of studies which I am unfamiliar with, or is there some reason to
>believe that the treatment of identical twins after separation is
>substantially different from the treatment of fraternal twins after
>separation?
>
>
> Topher Cooper
>
>USENET: ...{allegra,decvax,ihnp4,ucbvax}!decwrl!pbsvax.dec.com!cooper
>INTERNET: cooper%pbsvax.DEC@decwrl.dec.com
> or cooper@pbsvax.dec.com
Topher Cooper's remarks are well-thought out and relevant.
His thoughts should be extended a little, though, I feel.
At first, there would not seem to be any reason to believe the treatment of
identical twins (after separation) should be substantially different from the
treatment of fraternal twins (after similar separation). And there may, in
fact, not exist substantive difference in treatment.
But what is difficult conceptually (and therefore, in practice) to control for
are phenotypically-based differences (factors, such as looks, which are
observable) between, on the one hand, the set of identical twins (basically
no obvious differences), and on the other hand, the set of fraternal
differences (plenty of obvious, overt differences, such as in their looks - say
handsome vs ugly).
If the fraternal twins differ only in LOOKING different (to the adult adopting
parents, etc), that fact ALONE MAY cause differential behavior TOWARD those
children, chain-reacting a cause and effect cycle that winds up as being
measured as "differences in intelligence (or behavior) "due to" genetic-based
differences!
Thus, while the difference observed within the set of fraternal twins
is demonstrably due to the fact of fraternal vs identical origins, the thesis
that the difference is DUE to neurologically-related differences in the
nervous system is NOT thus demonstrated! All that will have been
demonstrated, and I think most can agree has been demonstrated, is that the
differences observed are due to SOMETHING related to genetics - but one must
be very cautious, until a specific anatomical, biochemical, etc. analysis has
been done on the complete developmental structure of the brain to show one way
or another (which we are years away from being able to do) of drawing
the conclusion that psychological factors, such as intelligence, are
necessarily the sole initial CAUSE of later observed behavioral differences.
In other words, until such time as it will be possible to specifically
measure every aspect of TOTAL behavior, one may not conclude that a
genetic difference is solely (or at all) linked to a conjectured fundamentally
neurologically-based difference.
Bill Lieberman
------------------------------
Date: 21 May 88 20:03:15 GMT
From: mind!clarity!ghh@princeton.edu (Gilbert Harman)
Subject: Re: Twin studies (was AIList V6 #86 - Philosophy)
Could someone please post references to the twin studies
being referred to? I am only familiar with older ones that
have turned out to be based on fraudulent data.
Gil Harman
Princeton University Cognitive Science Laboratory
Princeton, NJ 08542
ghh@princeton.edu
HARMAN@PUCC.BITNET
------------------------------
Date: 27 May 88 19:46:50 GMT
From: dan@ads.com (Dan Shapiro)
Reply-to: dan@ads.com (Dan Shapiro)
Subject: Re: [DanPrice@HIS-PHOENIX-MULTICS.ARPA: Sociology vs Science
Debate]
I'd like to take the suggestion that "bigger decisions are made less
rationally" one step further... I propose that
irrationality/bias/emotion (pick your term) are *necessary*
corollaries of intelligence - that they arise because of the need to
make decisions on partial information, to fill in "the gap", so to
speak, between what an agent knows and the responses it might apply.
The claim is that it is not in general possible to prove one's way
from situation and goals to action, and that some force encoding bias
is required.
I.e., if you place a donkey between two equally attractive bales of
hay, it doesn't starve. It chooses the left one because it *likes*
the left barrel of hay.
In a deeper form, this is an argument against deductive planning as an
action selection technique.
------------------------------
Date: 27 May 88 22:31:07 GMT
From: ejs@orawest.sri.com (e john sebes)
Reply-to: ejs@orawest.uucp (e john sebes)
Subject: Re: [mcvax!ukc!its63b!aiva!jeff@uunet.uu.net: Re: Sorry, no
philosophy allowed here.]
In article <19880527050233.8.NICK@MACH.AI.MIT.EDU>
>
>In article <1069@crete.cs.glasgow.ac.uk> gilbert@cs.glasgow.ac.uk
>(Gilbert Cockton) says:
>> If you can't write it down, you cannot possibly program it.
>
>Not so. I can write programs that I could not write down on paper
>because I can use other programs to so some of the work. So I might
>write programs that are too long, or too complex, to write on paper.
Yes so. You can write such programs (such as a YACC application) because
someone else has written the other program (such as YACC). And that
someone else couldn't have written that other program unless he could
have written it down, or used some other other program.....
If you want to be more precise, try this version of Gilbert Cockton's remark:
If nobody can write it down, then nobody can possibly program it.
I should have hoped that the essential point was obvious.
If anyone really beleives that programming languages are some kind of
priviledged formalism in which otherwise impossible things become
possible, I'd like to hear their views.
--John Sebes
------------------------------
Date: Fri, 27 May 88 23:04:18 -0200
From: Antti Ylikoski <ayl%hutds.hut.fi%FINGATE.BITNET@MITVMA.MIT.EDU>
Subject: the human mind as a logical system
It would seem that the human mind is very fault-tolerant with respect
to locigal oddities.
Example: a human being can be a queer reasoner in the sense of
Smullyan.
I recall that a queer reasoner believes a proposition p (Bp) and
simultaneously believes he/she doesn's believe p (B - (Bp)), the minus
sign denoting logical negation.
Let John be a true believer of some obscure faith. Say the Tur
religion by Edgar R. Burroughs in his Tarzan books.
Let p be the proposition "Tur exists".
Let John lament his lack of faith to a Tur priest.
Then John believes in Tur (Bp) but believes he doesn't believe in Tur
(B - (Bp)).
Andy Ylikoski
------------------------------
Date: 28 May 88 11:20:19 GMT
From: cae780!leadsv!esl!ssh@hplabs.hp.com (Sam)
Subject: Re: Symbolics stock
->marsh@mbunix (Ralph Marshall) sez ->
->Summarized advice:
->1) Face squarely in directions of Symbolics shares.
->2) Turn 180 degrees.
->3) Run like hell; don't look back or you turn into a pillar of cons cells.
->
->Symbolics sells GREAT software; they just can't push boxes worth a damn.
->Their equipment is way too expensive for deliverable systems in almost any
->realistic situation, their maintenance costs even for research use is
->exhorbitant, and they don't seem to get the message from what customer
->base they have left.
...(More stuff deleted)...
For this reason I've recommended any project I've been related with
NOT be Symbolics-based for the last four years. Obviously, I'm not
alone.
I also regret that many mistakes killed the D-machines from Xerox,
which were great to work in/on, but were doomed by brain-damaged sales
/ marketing strategists at Xerox.
-- Sam
------------------------------
Date: 29 May 88 01:57:42 GMT
From: glacier!jbn@labrea.stanford.edu (John B. Nagle)
Subject: Re: Symbolics stock
I don't know of anybody buying Symbolics boxes in quantity around
here. Everybody seems to have a few, but no new ones are being acquired.
Besides, they're no longer a status symbol; nowadays you have to have a
Connection Machine to impress anybody. But the general machine for getting
work done seems to be a Sun III.
John Nagle
------------------------------
Date: 1 Jun 88 22:21:46 GMT
From: bbn.com!pineapple.bbn.com!barr@bbn.com (Hunter Barr)
Subject: Re: Symbolics stock
In article <692@esl.UUCP> ssh@esl.UUCP (Sam) writes:
>->marsh@mbunix (Ralph Marshall) sez ->
<Both posters bash Symbolics for being expensive and unresponsive.>
I'm no investment expert, but it looks to me like you have Symbolics
confused with LMI. LMI hung on at the edge of bankruptcy for a very
long time, whereas Symbolics seems to gave plenty of cash to see them
through this development cycle and into the next one. All the
indications are that the coming batch of hardware and software is very
solid.
Symbolics is taking exactly the right steps to get out of the "box"
business, by putting their effort into the Ivory chip and their
software development. As someone who uses Symbolics Lisp Machines
regularly (as well as VAXen, SUN workstations, and other machines), I
can tell you that their latest release of software (Genera 7.2) shows
that they are responsive to the demands of the market:
It contains many popular improvements and enhancements.
It was delivered on time.
It marks the return of the "source included" policy, with a very
reasonable price. It actually contains more of the source than
7.1 even without the fee!
I don't have enough money to outfit my VAX or SUN like a Lispm; the
memory, software, and OS source-code licenses are far too expensive.
Moreover, it is obviously going to be a couple of years until the
development tools on these machines catch up to where Lispms are now.
(I am betting on Saber C, but maybe SUN's SPE will surprise us.)
If I did have that much money, I would buy more Symbolics stock. I
think the only way they are going out of business is if they are
bought by Sony, or DEC, or a very big defense contractor.
In almost every large project on which I've worked, there has been
some component which was best implemented on Symbolics machines,
usually for its development environment, but sometimes for the unique
hardware itself. I will continue to recommend them where they are the
best solution, which I expect to be often.
______
HUNTER
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End of AIList Digest
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