Assume IQ is 100% genetic. Take 2 societies of 100IQ. In A, 3 generations of women only mate with men averaging 130IQ (by force and/or choice). In B, the same only mate with 70IQ. What are the resulting averages of IQ for A and B, and how long did it take for those to appear?
-
-
-
Ok, with assumptions and vague chemistry mixings notions. 100 + 130 ÷ 2 = 115. Don't understand regression to mean. Suspect 130 is wrong? Should still be men at 130 though. 115 + 130? ÷ 2 = 122. 128 129 130 .... 5 generations.
-
Regression to the mean means that once the selective regime ends and mating is randomized, the averages will fall back toward the original population mean. In this case, assuming just the first generation comes out 115 and starts mating randomly, it regresses back to 107.5 in 2nd
-
Here are some simulations that graphically illustrate regression the mean http://jsmp.dk/posts/2018-10-10-rtm/ …http://jsmp.dk/posts/2018-10-10-rtm/ …
-
So regression to the mean mostly effects the first generation. Also, I should have skewed by 70% heritability. 100 + (130 - 100) × .7 / 2 = 110. What factor is missed in this first generation, or included in the next for regression? 110 + (130 - 110) × .7 /2 = 117.
-
Regression only affects the first generation.
-
Why? Or how? or do I have this right? Ex, If 130s men mate with 100 average women, then we have a regression to 100, assuming heritability of .7, we get a new mean of 110. If the next generation does the same, is the regression to the new mean of 110?
-
My example and Jonatan's are fundamentally different in that I'm positing severely selective mating (not just assortative mating) and therefore the regression effects will mostly be seen once the selection is removed and the population mates randomly amongst themselves.
- 3 more replies
New conversation -
-
-
Most of the points in the article can be rebutted. I've heard about the Irish IQ increase before, but I don't know enough about it to know if there's an obvious rebuttal. Anybody? The claimed 10-point black-white gap -- isn't that based on proxy (e.g., NAEP) data?
- 1 more reply
New conversation -
-
-
The comments section is priceless - a cesspool of virtue-signaling and naive, uninformed rationalizing of the 'morally correct' view.
Thanks. Twitter will use this to make your timeline better. UndoUndo
-
-
-
Indeed. And the higher the within-group heritability is, the more harsh the environment needs to be for many of the individuals in the group with the lower average IQ score for the group differences to be only (or largely) a function of environmental differences.
Thanks. Twitter will use this to make your timeline better. UndoUndo
-
-
This Tweet is unavailable.
-
-
They're admiting there's a gap?!
Thanks. Twitter will use this to make your timeline better. UndoUndo
-
-
-
"...recent research suggests that intelligence is about two-thirds biological and one-third environmental. That amount of environmental influence is more than enough to account for the black-white IQ gap." Strange logic here...
Thanks. Twitter will use this to make your timeline better. UndoUndo
-
-
-
Lotta things wrong here. If Drum doesn’t think trait selection can occur within 40,000 years he’s high. Intelligence isn’t one large trait but a serious of smaller ones working collectively. Pro-environment arguments for racial IQ variance do not preclude genetic determinism.
- 1 more reply
New conversation -
Loading seems to be taking a while.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.