Re: Flynn Effect ...yes, testosterone

Bryant (
7 Nov 1996 09:42:09 -0700

In article <55oef4$>,
James Howard <> wrote:

>Well, I guess I misinterpreted "worldwide," from my source. However, I
>suggest the remainder of your information is in total agreement with my
>hypothesis. You see, I predict that increases in testosterone are adversely
>affecting development of the "verbal" side of the brain. The Flynn Effect is
>mainly an increase in nonverbal IQ.

There does seem to be an association between androgens and verbal IQ.

>Therefore, according to my
>interpretation of this real, small increase (see just below), the Flynn Effect
>should affect Blacks more than Whites. Blacks produce more testosterone
>(see some of my other posts for the citation).

Blacks also occupy the lower SES disproportionately, and low SES whites
are enjoying Flynn Effect benefits as well. In Denmark, I believe, a
study on Flynn Effect IQ gains showed that almost all of the change was
in the lower IQ folks' improvements. That's why some of us working on
this topic believe that environmental insults account for IQ differences
between races or populations. There may be another correlation between
these factors and testosterone, I suppose, but we shouldn't reject the
role of improved developmental environments just yet.

>You mention that this effect is occurring most rapidly in the "lower end of the
>IQ score distribution." I know this is true, and it may be a bad sign, not a
>good one. You imply that "improvements..." are the source of the Flynn
>Effect in Blacks. That may be true, but it may just make things worse. (I do
>not want to be misinterpreted here. I think the very best civilizations should
>do these things for the most vulnerable, and I am thankful I live in one.)
>However, these improvements will increase the numbers of people who are
>higher in testosterone.

One of the problems with Eugenics is that what constitute "good genes" in
the present environment can very quickly become "bad genes"... if the
good of humanity is the concern you're addressing, maintaining as much
genetic variability as possible should be your goal.

>That is, these improvements increase the "feed and
>breed" phenomenon. If you will reread my "Current signals of testosterone,"
>you will read that young Black teenagers are rapidly reproducing, compared
>to their older counterparts, who already are reproducing faster than Whites.

If testosterone production is so heritable as you suggest here, how is it
that you assert dramatic increases in androgen levels between generations?

Am I misunderstanding you?

>It is also known that violence, among Blacks, is greatest among the very

Violence among disenfranchised young *males* is very high. There are a
number of socioecological factors in ghetto neighborhoods which can
account for the high representation of black men in violent and property

>This has already been found in a Danish study of 1987. "We present data
>showing a substantial increase in both the intelligence test scores and
>educational levels of 71,678 Danish males born between 1939 and 1958.
>However, a decline in the test scores within the highest educational levels
>accompanies the increase in proportions attaining those levels." Nature
>1987; 325: 119

Thanks for the citation.

The upper limit to IQ suggests that there is, after all, a species-typical
developmental "target" for intelligence which is compromised by developmental
stressors (hence, the increases we discussed above are happening at the lower
tail of the score distribution).

>I interpret this to mean that Danish males are increasing in
>testosterone levels, and that it is beginning to affect their brightest. That
>is, I think testosterone is beginning to adversely affect the entire brains of
>this population. (Hopefully, this will allay some of the "enlightened" or

Is there data on Danish hormone levels changing?

>15 points were gained in two generations. Fifteen points over 20 to thirty
>years is less than one point increase per year. This is small!

If 15 points is small, then we need not concern ourselves with mean IQ
differences between racial groups. I think I disagree. While I don't
believe that IQ is a unidimensional measure of "merit" or "ability" (as
some IQ researchers apparently do), I do believe that the components of
intelligence captured by IQ tests constitute potentially important parts
of social success.

I'm not rejecting your ideas outright, by the way; 'just presenting some
viable alternative explanations. While I agree that brain size and IQ
correlate, I disagree with your contention that this correlation is
causal. I think that it's a loose correlation caused by a common
underlying developmental factor (that is, a factor behind both IQ and
brain size).

I do believe that Eugenics thinking is tricky--we have learned repeatedly
(speaking for myself, just in the past year!) that a perfectly obvious
and intuitive correlation can fall away when confronted with new data.
Besides which, what is adaptive is necessarily context specific, and not