I have asked Helmuth Nyborg how it is possible that average western IQ is going down and keeps growing at the same time, as he claimed in https://lesacreduprintemps19.files.wordpress.com/2011/04/nyborg-2011-the-decay-of-western-civilization-double-relaxed-darwinian-selection.pdf? He responded that Flynn effect (test smartness) measures the "phenotypic IQ" whereas
The dysgenic effect of low-IQ immigration and internal condition, in which low-IQ parents have fewer children than high-IQ parents is a g-effect, driving genotypic IQ Down.
He says that
Arthur Jensen describes these tendencies in his famous book: The g factor, published in 1998 on Praeger Press."
Indeed, this makes sense but I do not understand how can these psychologists measure the genotypic IQ? I believe that IQ is a phenotypic manifestation of the genotype. DNA has no brain to measure the intelligence. Yet, genotype can develop into a phenotype. The only way I see that you can measure the genetic IQ is after the genotype has developed into a phenotype. Therefore, phenotypical and genotypical IQ is the same thing. I therefore do not understand how there can be difference between genotypical and phenotypical IQ. What are they talking about? How do they measure it? Is it just fascist nonsense?
12 Dec 2013 From recent email from Nyborg
If you adjust for heritability by multiplying measured IQ by, say, .6, .7, or .8 (depending on how heritabable you find IQ is), you get a rough estimate of “genotypic” IQ (a term that may be slightly misleading, as you have not factually accounted for the genetic basis of IQ). The Flynn rise in IQ possibly has to do with factors like testsmartness, nutrition, environmental stimulation etc.