Did Ireland used to be dumb? A look at eminent scientists

Some researchers have claimed that the average IQ of the Irish used to be really low by West European standards but has recently caught up, and this shows that IQ can be raised by improving social conditions. 

Russell Warne recently conducted an analysis of 55 samples of 29k Irish examinees, the IQ data collected in various years from 1916 to 2015. The mean was found to be 98.0. As you see in his graph below, there was at most a slight increase in mean IQ over this period. This pattern contradicts the optimistic nurturist view. 

 

A reality-check approach might offer a nice complement to the IQ data. If mean Irish IQ were, say, 85 a century ago, we should not expect Ireland to have produced many eminent scientists. 

I will rely on the inventories of significant scientists, mathematicians, and technologists listed in Charles Murray's Human Accomplishment. I will use Scotland, Denmark, Norway, and Finland as comparisons. They are NW European countries with population sizes roughly similar to that of Ireland, and as far as I know, no one has claimed that those countries used to be low-IQ. 

You can see from the lists below that Scotland smokes the other countries with 57 significant figures. Pound for pound, Scotland is an impressive country. Denmark is a distant second with 14 eminent men, but Ireland is a close third with 13 significant figures. Norway has 8, and poor Finland only has one. Impressive country but not for its past scientists. 

So Ireland falls to the middle of the pack. No reason here to think that the Irish used to be dumb but have only recently improved their intelligence level.  

Scotland -- 57 Significant Figures

Astronomy
Thomas Henderson

Biology
Robert Brown
John Haldane
John McCleod

Chemistry
Archibald Couper
John Cranston
William Cullen
James Dewar
Alexander Fleck
Thomas Graham
Charles Macintosh
William Ramsay
Daniel Rutherford
James Swinburne
James Waterston
James Young

Earth Sciences
James Ewing
James Hall
James Hutton
Charles Lyell
William Maclure
Roderick Murchison
William Nicol
Charles Thomson

Physics
David Brewster
James Maxwell
William Thomson
Charles Wilson

Math
James Gregory
Colin Maclaurin
John Napier
James Stirling
Joseph Wedderburn

Medicine
Charles Bell
Alexander Fleming
John Hunter
James Lind
Patrick Manson
Edward Mellanby
John Pringle
James Simpson
Robert Whytt

Technology
John Baird
Alexander Ball
Patrick Bell
James Dewar
Kirkpatrick Macmillan
John McAdams
Andrew Meikle
William Murdock
James Nasmyth
William Rankine
James Thomson
William Thomson
Robert Watson-Watt
James Watt
James Young 

Denmark -- 14 Significant Figures

Astronomy
Tycho Brahe
John Dryer
Ejnar Hertzsprung
Ole Romer

Biology
Peter Dam
Johan Fabricius
Hans Gram
Wilhelm Johannsen

Chemistry
Soren Sorensen

Earth Sciences
0

Physics
Erasmus Batholin
Niels Bohr
Hans Orsted

Math
0

Medicine
Niels Finsen

Technology
Valdemar Poulsen

Norway -- 8 Significant Figures

Astronomy
0

Biology
0

Chemistry
Cato Guldberg

Earth Sciences
Jakob Bjerknes
Vilhelm Bjerknes
Peter Waage

Physics
0

Math
Niels Abel
Marius Lie
Caspar Wess

Medicine
Johannes Fibiger

Technology
0

Finland -- 1 Significant Figure

Astronomy
0

Biology
0

Chemistry
0

Earth Sciences
Johan Gadolin

Physics
0

Math
0

Medicine
0

Technology
0

Ireland -- 13 Significant Figures 

Astronomy
William Parsons

Biology
John Tyndall

Chemistry
Thomas Andrews
John Bernal
Adair Crawford

Earth Sciences
Francis Beaufort
Edward Sabine

Physics
George Fitzgerald
George Stokes
George Stoney
Ernest Walton

Math
0

Medicine
0  

Technology
Arthur Kennedy
Charles Parsons

How much has mean IQ declined in the US?

 I looked at General Social Survey data to see how much IQ has declined in the US since the early 70s when the GSS was started. I set whites tested in the 70s to a mean of 100, so they are the comparison group. Here's what I found: 

Mean IQ for the 2010s is 99.6, so compared to 1970s whites, the mean has dropped very little. It didn't drop more since we see a Flynn effect among all racial groups. The negative impact occurs because of the tremendous growth of Hispanics who have a 2010s mean IQ of 94 shown below. (All numbers exclude immigrants since they are likely to do poorly on an English-language IQ test). 

Data: The four point Flynn Effect among US blacks (but pay no attention because Taleb says IQ is crap)

According to General Social Survey (GSS) data, both whites and Mexican Americans born in the US have experienced mean IQ drops in the past decade.  Is this also true of blacks?  Here are the means by decade (N = 3,865):

Mean IQ

1970s  88.0
1980s  89.0
1990s  90.8
2000s  92.1
2010s  92.4

The 70s/80s increase was 1 point; the 80s/90s was up 1.8 points; and it was up 1.3 points for the 90s/00s.  The past decade witnessed the smallest increase of 0.3 IQ points.  The 1970s-2000s gain is impressive, but lately things seem to be slowing down.

I don't how to explain the trend but suspect that American society might expose blacks and whites (via schools, mass media, etc.) to more similar words used to test vocabularies than in the past.

The typical IQ mean you read about for black Americans is 85, but the black/white verbal IQ gap appears to be smaller: GSS data indicates that in this decade the gap is six-tenths of a standard deviation.  Notice how the black mean is a point higher than the 91.5 mean for Mex-Ams reported in a recent post.       

Data: A negative Flynn Effect among Mexican Americans

About a decade ago, I documented an impressive rise in the mean IQ of Mexican-Americans born in the US.  Using GSS data, what is the trend in this decade?  Look at the graph (N = 609):

The mean was only 85.0 in the 1970s and 84.7 in the 1980s, but it rose all the way to 94.7 by the 2000s.  From this trend, one might get the hope that Mex-Ams might someday converge with the white average of 100.

But it was not to be. The trend has reversed in this decade, and the mean has fallen back down to 91.5.

I don't know how we explain these trends. Dysgenic trends would manifest themselves slowly.  We have seen a recent downward turn among several European populations.

The samples sizes for each decade are not large (this decade included 217 people) so some of the trend might be noise.

Assuming the 91.5 average is more or less correct, this is a bad sign for America.  A person with an IQ in the low 90s will be unable to do many of the jobs that we need done.  Such a population will have more social problems and little high-level achievement.

UPDATE:  I looked at all Americans born in the US (N = 25,116) and found a seven-tenths of a point drop in IQ from the last decade to this one.

Study: Flynn effect is not caused by hybrid vigor

From Psychological Review:

Mingroni (see record 2007-10421-011) proposed that heterosis or hybrid vigor may be the principal driver of the Flynn effect—the tendency for IQ scores to increase at a rate of approximately 3 points per decade. This model was presented as a resolution to the IQ paradox—the observation that IQ scores have been increasing despite their high adult heritability—on the basis that substantial changes in IQ can only be accounted for by changes in underlying genetic factors. It is here argued that this model is predicated upon a misconception of the Flynn effect, which is most pronounced on the least g-loaded components of cognitive ability tests and is uncorrelated with genetic effects such as inbreeding depression scores (which are correlated with the g loadings of tests). Evidence supportive of the recently proposed life history model of the Flynn effect is presented. In the discussion, other theoretical objections to the heterosis model are also considered. On this basis, it is concluded that the Flynn effect is strongly entwined with developmental status and that heterosis cannot be its principal cause.

White birth cohorts and Wordsum

The table shows mean Wordsum scores for whites born in various decades and measured each decade starting in the 1970s through 2008 (GSS data). Looking at whites born in the 1950s, the mean jumps up from 6.01 when they were in their twenties (in the 70s decade) to 6.55 in their thirties. You see a similar increase for the 60s birth cohorts from the 1980s to the 1990s. (Increases for both groups are statistically significant). This shows that voculabary grows during one's twenties. There are not significant increases as people move into their thirties and beyond (although the 30s-40s increase for the 1950s cohort is close to statistical significance).

This is an interesting finding. I knew that vocabulary was loosely correlated with age, but it looks like the gains are made specifically in one's twenties. People are probably expanding their vocabularies as they are required to learn less common words in college and at the workplace. Also, this finding reminds us that cohort, period, and age effects complicate the study of the Flynn effect.

White Americans born in the 40s and 50s end up with Wordsum averages that are significantly higher than that of the 1930s birth cohort. Those born in the 1960s, however, end up with a mean not significantly different than for those born during the Depression.

Something happened to people born in the 40s and 50s--the Baby Boomers, roughly--that gave them larger vocabularies than the cohorts before or after them. The improvement over the 30s cohort seems understandable, but why the decline in the 60s cohort? The 70s cohorts looks like it will end up the same as those born in the 60s. It seems like something has slipped among whites in the past few decades. Explanations like nutrition don't seem to work. I'm not sure how family change would make a big difference. Declining educational standards? Less reading?

NAMs and the Flynn effect: In the last post on the Flynn effect, I used GSS data to show that the mean Wordsum scores of people born in the United States of Mexican and Puerto Rican descent have risen over the past two decades. I list below the mean scores for a larger number of ethnic groups over the past four decades.


Mean Wordsum scores

Mexican
Seventies 4.17
Eighties 4.04
Nineties 5.11
This decade 5.53*

Black
Seventies 4.82
Eighties 4.91
Nineties 5.10
This decade 5.38*

Amerindian
1972-1989 3.68
1990-2008 4.47

English/Welsh
Seventies 6.70
Eighties 6.74
Nineties 7.00
This decade 6.95

German
Seventies 6.14
Eighties 6.22
Nineties 6.28
This decade 6.40

Irish
Seventies 6.47
Eighties 6.30
Nineties 6.49
This decade 6.59

Italian
Seventies 6.11
Eighties 6.08
Nineties 6.43
This decade 6.47

Polish
Seventies 6.28
Eighties 6.43
Nineties 6.47
This decade 6.23

Scottish
Seventies 7.08
Eighties 6.54
Nineties 6.77
This decade 7.03

Jewish
Seventies 7.42
Eighties 7.58
Nineties 7.32
This decade 7.47

* Significant change between first and last period, .05 level, two-tail test.


The American Indian sample size is very low after you remove blacks and whites who say their main ethnicity is Native American, so I had to limit the comparison to two periods. The difference between the two would very likely be statistically significant if the sample were larger.

There is a clear pattern here: none of the white groups have seen significant improvements since the early 1970s when the vocabulary test was first given, but all of the non-white groups have improved. I suggested before that fewer NAMs have good English language models, but the increased hours of television viewing might have helped compensate in the last couple of decades. Kids watch several hours of TV each day, and they often watch peers that they want to imitate. Characters on television usually speak well. (Of course, it doesn't help if they are speaking another language well). White kids often have good models anyway, so people on television with good vocabularies are redundant.

Anyway, that is one explanation, but others ideas to account for the pattern are appreciated.

(TV can't be THAT powerful, or generations wouldn't continue to have strong accents.)