Sunday, May 31, 2009

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.)

5 comments:

Beastmaster said...

Is this test available on the internet?

BGC said...

I think it is probably due to improved nutrition during gestation and very early childhood - with some groups having reached a plateau of improvement earlier than others.

***

Richard Lynn. What has caused the Flynn effect? Secular increases in the Development Quotients of infants

Intelligence. Volume 37, Issue 1, January-February 2009, Pages 16-24

Abstract

Results of five studies show that during the second half of the twentieth century there were increases in the Development Quotients (DQs) of infants in the first two years of life. These gains were obtained for the Bayley Scales in the United States and Australia, and for the Griffiths Test in Britain. The average of 19 data points is a DQ gain of approximately 3.7 DQ points per decade. Similar gains of approximately 3.9 IQ points per decade have been present among preschool children aged 4–6 years. These gains are about the same as the IQ gains of school age students and adults on the Wechsler and Binet tests. This suggests that the same factor has been responsible for all these secular gains. This rules out improvements in education, greater test sophistication, etc. and most of the other factors that have been proposed to explain the Flynn effect. It is proposed that the most probable factor has been improvements in pre-natal and early post-natal nutrition.

CMA said...

Before we start theorizing,

SAT Verbal scores shows no improvement among Mexicans over the last 20 years: http://nces.ed.gov/programs/digest/d07/tables/dt07_134.asp

NAEP reading scores for Hispanics don't show this reliable pattern of improvement relative to whites either: http://nationsreportcard.gov/ltt_2008/ltt0009.asp?subtab_id=Tab_2&tab_id=tab3#chart

So this is maybe just a change in the sort of people who are taking the survey? You'd know the methodology much better than I, but it looks more like Mexicans are just beginning to take their expected Wordsum position between white and blacks (although improved nutrition/education probably did boost black&Hispanic scores -on all tests- in the 70s).

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