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1884[evol-psych] Re: Iq" genetic or environmental?

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  • Paul Barrett
    Dec 3, 1999
      ----- Original Message -----
      From: Fredric Weizmann <weizmann@...>
      To: Peter Kabai <pkabai@...>
      Sent: 03 December 1999 16:39
      Subject: [evol-psych] Re: Iq" genetic or environmental?

      > Insofar as the heritability of intelligence is concerned it has "bounced"
      > between .2 and .8 in various studies.
      > changed in this regard,) however, citing a midrange value is no more
      > defensible than citing an extreme one. Irwin Silverman says its somewhere
      > betweem .5 and.7. Even if one accepted that the chimera
      > of a "true" heritability lay within this range, it would still reflects a
      > difference between accounting for 25% of the variance and 49%--so thats
      > not exactly a definitive claim.

      My understanding of heritability estimates is that they represent the
      proportion of phenotypic variance that can be accounted for by genetic
      effects. As such, they are already "estimates of explained variation" - and
      are referred to as genetic "correlations" in studies where environments are
      "non-shared". The figure (7.2a) on page 179 of Jensen's book "The g Factor)
      shows relative proportions of genetic and environmental effects.

      Regards .. Paul
      Paul Barrett Direct Tel: (44)-1555-841343
      email: p.barrett@... Hospital Tel: (44)-1555-840293
      CS2000: pbarrettx1@... Fax: (44)-1555-840024

      Chief Scientist, The State Hospital, Carstairs, Scotland, ML11 8RP, UK
      Senior Research Fellow, Clinical Psychology, Liverpool University, UK
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