Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!mcvax!ukc!edcastle!edai!cam From: cam@edai.ed.ac.uk (Chris Malcolm cam@uk.ac.ed.edai 031 667 1011 x2550) Newsgroups: comp.ai Subject: Re: Inheritance of IQ Message-ID: <518@edai.ed.ac.uk> Date: 20 Aug 89 14:36:09 GMT References: <5453@pt.cs.cmu.edu> <2061@cbnewsh.ATT.COM> <5480@pt.cs.cmu.edu> <458@edai.ed.ac.uk> <18330@princeton.Princeton.EDU> <483@edai.ed.ac.uk> <18526@princeton.Princeton.EDU> Reply-To: cam@edai (Chris Malcolm) Organization: University of Edinburgh, Edinburgh Lines: 83 In article <18526@princeton.Princeton.EDU> rks@notecnirp.UUCP (Ramesh Sitaraman) writes: >>>In article <458@edai.ed.ac.uk> cam@edai (Chris Malcolm [me]) writes: >> >>You assert that there are essential characteristics which take a long >>time to respond to selective pressure, and external characteristics >>which respond rapidly. Evidence? >> >>You assert that IQ is one of the essential characteristics. Evidence? > >I agree that I have no evidence that IQ is such a characteristic. >It was only an (educated?) conjecture. Especially as we dont yet >know how to measure it. When we're talking about how easily a characteristic will respond to selective pressure (in the evolutionarily short term - i.e., not waiting around for new mutations to occur), the important question is how many factors (genes) influence the characteristic: if only a few, then the characteristic will occur, or not, in a relatively few forms; if many, then the characteristic will vary in a finely graded fashion. Colour blindness occurs in the 'switched' fashion characteristic of being affected by only a few genes, whereas intelligence (whatever it may be), seems to occur in a graded fashion. Therefore it should be affected by many different genes, and therefore it should respond easily, in a graded fashion, to selective pressure. Consequently, if you actually wished to breed for intelligence, just by using the simple breeding techniques used by animal livestock breeders, you could. This would apply whether you were breeding rats, dogs, or people. In fact, some working dog breeds, such as sheepdogs, have been selected by breeders for general intelligence, among other things, and as a consequence are smarter - on average - than the average dog. Of course, in any selection program, sooner or later you come up against the limits set by the gene pool in question, and then you have to wait for new mutations. In some cases, the natural population has already been selected so severely for the characteristic in question that it is already at the limits. In these cases the individuals will show little variation in that characteristic. I think I read somewhere that cheetahs were pretty much at their genetic limits as far as speed was concerned. But the observed considerable natural variation in human mental performance argues against human intelligence being up against the genetic stops in this way. Indeed, since our language and culture are such an effective way for the many to benefit from the insights of the few, the best evolutionary strategy for humanity would seem to be a population which produced extreme sports of variously specialised mental talents, even to the extent where these might be individually disadvantageous, against a background level of general docility. Note, for example, that genius is not simply being very smart at something or other, there is also the important sweat factor, i.e., the temperament which produces the necessary devoted hard work. >>Note that the largest and most rapid recent evolutionary change which >>the human race has suffered is a very considerable change in brain size; > >Is this really true ? The Neanderthals are supposed to have had >a bigger brain than us but they were certainly not more intelligent. >In fact Neanderthal sites round the world shows such remarkable >similarity indicating a complete lack of innovation. Yes, but as you go on to point out, there may be very important _social__ differences. For example, maybe the _average_ Neanderthal was _more_ inteligent than the average human today, but Neanderthal language and culture wasn't up to the task of benefitting from the insights of the few. The average human is a rotten innovator, he just happens to be very good at copying the innovations of the occasional human genius. >I don't think we have become any cleverer in the past 50,000 years >or so (in terms of intrinsic cleverness). In my understanding, >the evolutionary change that anthropologists propose >that caused the so called "great-leap forward" is the of the larynx >that helped us communicate with a larger variety of sounds. With >this new communication, we could collectively utilise the brain >power of the entire community past and present and what this >resulted in is history ! > > Ramesh Quite so. You have explained the wonderful mechanism by which the human race can collectively get round to sending a man to the moon, despite the fact that most individual humans couldn't even invent a mousetrap. -- Chris Malcolm cam@uk.ac.ed.edai 031 667 1011 x2550 Department of Artificial Intelligence, Edinburgh University 5 Forrest Hill, Edinburgh, EH1 2QL, UK