On 23 Apr 2004 09:23:26 -0500, [EMAIL PROTECTED] (Herman Rubin) wrote: > In article <[EMAIL PROTECTED]>, > Richard Ulrich <[EMAIL PROTECTED]> wrote:
> > Good studies have demonstrated that the most important factor > is purely genetic. Identical twins reared apart are more > similar that fraternal twins reared together, and in some > cases than identical twins reared together. Of the effects that they measured, genes were important. There is that generational effect, where IQ increases by 3 points per decade since 1950, which lies on top of that. It sounds to me like you never did read about the Flynn effect, which I pointed you toward during an exchange in December, 2003: ======== start of extract from sci.stat.edu, Dec 4: [ RU here is message prior to Dec 4. Dec 4 has no initials.] RU > > >Yes, IQ scales are periodically re-normed. That is > >the STRONG, world-wide evidence for the Flynn > >effect -- the fact that researchers discovered that > >everyone around the world has to make the tests > >tougher, by a few points every decade, to keep the > >averages for normals at 100. HR > > Are the tests tougher? Or has it become memorization > and regurgitation, with the practice on taking multiple > choice tests raising the levels? The test designers are > very poor at thinking themselves, and thus have eliminated > this part from the tests. Besides, it is very difficult > to test thinking at all on multiple choice tests. > Herman, you are floundering so bad here, you must be totally out of touch with psychometric literature. " memorization ... multiple choice ... the test designers... ". The Flynn effect was first documented in the standardization of IQ tests. *YOU* have been willing to talk about IQ tests as if they measured something real. A decade or so ago, one obvious "explanation" was that kids were being crammed with facts, etc., for the tests. But further study shows that big surprise: improvement seems to be biggest on the tests like the Raven Progressive Matrix that are the best regarded measures of 'g' or fluid intelligence or the ability to think fast (as opposed to crystallized intelligence or mere knowledge). I haven't been keeping up, so I googled on <"Flynn effect" FAQ> . The first hit led me to http://www.indiana.edu/~intell/flynneffect.html which seems like a competent overview. That pointed me to a Flynn summary published in the American Psychologist, 1999, vol. 54, 5-20, which was also good. And has further references. ===== end of extract. Back to current. RU> > > >And then there is this complication: Our measured IQ strongly > >does reflect something cultural and educational, particularly for > >those tests of 'abstract reasoning' (Raven's progressive matrices) > >that still are (I think) regarded as having the strongest genetic > >loading. > > I doubt that the psychologists can understand abstract > reasoning, especially that it is not incremental. The Here at Pitt, the Grad. school in psychology used to depend heavily on an Analogies test, with (I estimated) an entry level of at least IQ 130. Is that abstract in the right way? > place where it is most clear is in mathematical concepts, > and few outside of abstract mathematicians even see these, > which can be understood without too much difficulty by > children, but apparently not by those in "education". ... and the above seems, mainly, invidious. > > > - By the way, Herman -- > >Do you have any reference for your description of the 'better > >scaling' for IQ, with bigger 'real' differences at the high end, or > >is that personal, subjective opinion? I do not remember that. > > It is partly subjective, but all of the "old" IQ tests, > produced before the introduction of the normal distribution, > have IQs ranging well over 160, including estimates of more > than 200. It was admitted that it was hard to measure at > this level, but this does not mean that scores above 130 > should not be reported. Pragmatically, the IQ should be 'linear' with something, if it is going to be useful as a measurement. Isn't this one of your own guidelines, or an immediate corollary? The statistician who first mentored me in 1970 offered the observation that there was very little 'functionality' for IQs that have been measured above 135 or 140 -- it did not translate to academic success (and IQ is strongly related to previous academic preparedness). Nor did extra-high IQ predict success in business. So. I did not know that recent tests were truncating the top end, but I find it easy to believe that the truncation of the score would be for linearity. It may take an IQ of 130 or so to become a successful theoretical physicist or mathematician, as I recall reading, but the points above that are mostly wasted. (I joined Mensa when I was 19; I was not impressed at the couple of meetings I went to, though I still imagine that the high IQ points were measuring *something*.) I have read something else that relates. Regression-towards-the-mean between parents and children does exhibit a bit of what you describe: Smart parents *do* tend to have children who score a bit higher than predicted from the scores, as scaled. Thus, your modification of the scale -- stretching the top -- would correct that bias. However, the discrepancy was not huge, and I don't find the alternate explanation difficult to accept: Namely, those same parents are better off economically and do encourage their children, so the extra points arise from simple social advantage. -- Rich Ulrich, [EMAIL PROTECTED] http://www.pitt.edu/~wpilib/index.html . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
