[extropy-chat] Why Progress Might Slow Down

[CurtAdams at aol.com]

In a message dated 11/4/2003 6:16:21 PM Pacific Standard Time, 
rhanson at gmu.edu writes:

>Maybe you should read the paper first?  The topic is average changes, not
>the change in each possible case.

I did.  They were citing the (well demonstrated) heritability of intelligence
(ie. the correlation between relatives, so more or less what I was talking 
about)
as evidence for heterosis as a major effect in IQ increase. My point is that
fact is evidence *against* heterosis.  High heterosis shows up as large
effects neither heritable nor enviromental and will be noise on almost any
study I've seen.  The main effect of heterosis is an otherwise inexplicable
similarity between siblings in that they will resemble each other but *not*
their parents.  

>>But, also with environmental change.  Feed people more, they mature
>>earlier and grow taller.   That's definitely an environmental change,
>>even though height is a highly genetically heritable trait.

>We don't actually know how much nutrition can account for height changes.

Not exactly. but there are large differences between sibs raised in different
countries.  It's certainly a major influence.

>>You need generations of strong isolation of small villages to get much
>>inbreeding
>>and the US and Canada were founded by individual or small family migrants 
from
>>the getgo.  There was never any inbreeding to dispose of.

>You might be right, but I don't think we have the data to support your claim
>with any confidence.

You could get it by looking at the ancestral villages of samples of people in
North American colonial villages.  I'd think somebody's done something like
that although I'd not know of it.  I have a friend studying American 
Revolutionary
history/sociology and I'll ask her if she knows anything on this.