New at Reason

December 1, 2006

Ronald Bailey mulls presentations by Charles Murray on James Flynn on the shrinking (or not shrinking) black/white IQ gap.

Comments

|12.1.06 @ 7:13AM|#

Doesn't the German study seem obviously flawed? GIs who knock up their temporary girlfriend while stationed abroad are obviously not a random sample. Indeed, they are heavily selected for a particular IQ range (smart enough to get into the military, dumb enough to have an unwanted child). All this study seems to show is that if you select the parents to be roughly equal, the kids will be too. That's not much of an insight.

|12.1.06 @ 8:08AM|#

Been seeing a number of interesting articles recently about intellegence differences between various populations. I'm surprised this one hasn't created more of an uproar:

http://education.independent.co.uk/higher/article2024763.

Although I suspect I will not have long to wait....

|12.1.06 @ 8:40AM|#

Ugh. That link didn't turn out so well. Try this one.

|12.1.06 @ 9:36AM|#

Pig, I think the Brit study you quote casts more doubt on the value of IQ tests than anything. If girls are dumber than boys but still do much better in school, then what good is all that extra IQ?

biologist|12.1.06 @ 9:51AM|#

Karen:

or it says schools and IQ tests aren't evaluating the same thing. IQ test proponents purport that IQ tests are evaluating innate intelligence. what do schools claim to be evaluating? usually, they're evaluating what the student actually knows and the student's ability to follow directions. the IQ test is more a measure of potential to learn, not the realized learning.

thoreau|12.1.06 @ 10:06AM|#

Yep, the difference between potential and achievement can be huge. I lived in the "honors" dorm as a college freshman. If I had a dime for every kid I met who bragged about his high test scores and IQ yet was failing freshman classes, I wouldn't have any student loan debt.

|12.1.06 @ 10:23AM|#

Well, I for one think that the obvious solution is large mandatory interracial orgies. No sacrifice is to big when racial equality is at stake.

|12.1.06 @ 10:24AM|#

I was under the impression that IQ tests measured the ability to do well on, well, IQ tests.

Is that wrong?

"Winston Churchill had a speech impediment and look what he did ..."

|12.1.06 @ 10:30AM|#

In black families...Dad comes home and says, "Hey, why don't we go out back and shoot a couple of baskets."

That assumes they have a Dad who comes home at all. The damage done growing up without a father cannot be underestimated. At least shooting baskets makes a connection.

|12.1.06 @ 10:40AM|#

I've had my IQ measured twice as a teenager. The numbers were pleasing to my ego at the time. Now, I'm completely unimpressed with the results. Too much is made of "intelligece" and too little is made of actual achievement. Of course, I still think I'm smarter than most people I know.

Yeah, I'm an egotistical, pompous ass. I know it. There's no need to point it out.

Mr. Gump|12.1.06 @ 10:51AM|#

Ahhm not a smart maaan, but I know what love iiis.

Thomas Paine\'s Goiter|12.1.06 @ 10:52AM|#

usually, they're evaluating what the student actually knows and the student's ability to follow directions.

Bollocks. Schools measure a student's ability to memorize and repeat.

Dan T.|12.1.06 @ 10:57AM|#

I was under the impression that IQ tests measured the ability to do well on, well, IQ tests.

Is that wrong?

That's true, but they also measure how closely your cultural background matches that of the people who wrote the tests.

D.A. Ridgely|12.1.06 @ 10:57AM|#

In fact, the average has risen by an astonishing 15 points in the last 50 years in the United States. In other words, a person with an average IQ of 100 today would score 115 on a 1950s IQ test.... According to Flynn, the average IQ for black four-year olds is 95.4, which drops to 89.4 at age 14 and widens further to 83.4 by age 24.

I trust that the average I.Q. score remains 100. Otherwise, if I read this correctly, the average I.Q. score for a black American over age 24 would be approximately two standard deviations below the norm. Can that possibly be so?

biologist|12.1.06 @ 11:04AM|#

TPG: if you memorized something, don't you "know" it? I'm not talking about comprehension. we're talking about the same thing.

Dan T.: test questions with obvious and demonstrable cultural (or sub-cultural) bias are usually thrown out, apparently without effect on the racial disparity in performance.

|12.1.06 @ 11:06AM|#

Apostate Jew had it right.

I.Q. tests are about as relevant as being a member of the nobility.

|12.1.06 @ 11:12AM|#

DA,

You read that incorrectly.
The score would be -1.1 standard deviations.
IQ tests have a standard deviation of 15 points.

The black/white IQ gap is about equal to the average difference between siblings, by the way.

|12.1.06 @ 11:16AM|#

Stereotype Threat is an important piece of this issue. There have been a growing number of studies demonstrating its existence.


J Appl Psychol. 2006 Jul;91(4):979-85.Click here to read Links

The difference isn't black and white: stereotype threat and the race gap on Raven's Advanced Progressive Matrices.

* Brown RP,
* Day EA.

Department of Psychology, The University of Oklahoma, Norman, OK 73019, USA. [e-mail]

This study addresses recent criticisms aimed at the interpretation of stereotype threat research and methodological weaknesses of previous studies that have examined race differences on Raven's Advanced Progressive Matrices (APM). African American and White undergraduates completed the APM under three conditions. In two threat conditions, participants received either standard APM instructions (standard threat) or were told that the APM was an IQ test (high threat). In a low threat condition, participants were told that the APM was a set of puzzles and that the researchers wanted their opinions of them. Results supported the stereotype threat interpretation of race differences in cognitive ability test scores. Although African American participants underperformed Whites under both standard and high threat instructions, they performed just as well as Whites did under low threat instructions.

|12.1.06 @ 11:17AM|#

the general public is not just uninformed but misinformed about the science of intelligence, particularly when it comes to group differences.

a useful summary signed by 52 researchers was published in the WSJ in 1994:

http://www.psychpage.com/learning/library/intell/mainstream.html

D.A. Ridgely|12.1.06 @ 11:44AM|#

MainstreamMan:

That's what I would have thought. However, if the average black 24 year old I.Q. was 83.4 and the overall average I.Q. were now 115, then a 2 SD delta would obtain. However, I assumed, in fact, that raw scores continue to be re-normed so that 100 remains the average score.

|12.1.06 @ 11:47AM|#

Dan T. "they also measure how closely your cultural background matches that of the people who wrote the tests."

You'll have a hard time explaining why minorities like Asians and Jews score significantly better on IQ tests than Whites, Hispanics or Blacks.

By your argument, IQ tests must all be written by Jewish-Asians.

It's amazing what fictions people are willing to believe, and what facts they will ingore, simply to hold on to their dearly-beloved ideologies.

biologist|12.1.06 @ 11:53AM|#

Mainstream Man, if that's the difference for siblings, then those results point to a strong effect of genetics. presumably siblings raised in the same household experience similar environments, but non-identical twin sibs share only half their genes on average

|12.1.06 @ 11:54AM|#

DA,

Yes. The scores are always standardized so that 100 is the mean.

|12.1.06 @ 12:00PM|#

Biologist,

I have seen that argument made.

However, there seems to be some structure to the sibling scores (can't find the citation at the moment) with birth order predicting many of the trends. This seems to indicate that even within a family, the context differs enough for each child that environmental factors can't be dismissed.

This study,

http://scholar.google.com/url?sa=U&q=http://www.aeaweb.org/annual_mtg_papers/2006/0108_0800_1302.pdf

provides evidence from adopted children that the effect of environment in adopted children is about equal to the black white gap found in the US.

|12.1.06 @ 12:09PM|#

IQ is highly heritable, and by adulthood the effects of shared family environment are undetectable.

For a review, see http://www.loni.ucla.edu/~thompson/PDF/nrn0604-GrayThompson.pdf


adoption studies find no correlation between the IQs of adoptive relatives in adulthood

McGue, M., Bouchard, T. J. Jr, Iacono, W. G. & Lykken, D. T. in Nature, Nurture and Psychology (eds Plomin, R. & McClearn, G. E.) 59-76 (American Psychological Association, Washington DC, 1993).

biologist|12.1.06 @ 12:19PM|#

Apostate Jew, since speech impediments have no correlation with intelligence, your statement is a non sequitur.

|12.1.06 @ 12:38PM|#

Mainstream Man,

Can you elaborate on these "stereotype threat" experiments a little? The abstract says that whites outperform blacks when the test is "threatening," but performance is equal when the test is "non-threatening." Does this mean blacks do worse when a test is "threatening," or that whites do worse when a test is "nonthreatening," or what? Is there a list of average scores in all six cases (two races x three threat levels) or something?

|12.1.06 @ 12:40PM|#

I.Q. tests are about as relevant as being a member of the nobility.

You know what we call people like you? "Little brains." Yeah, that's right: "little brains."

|12.1.06 @ 12:41PM|#

Apostate Jew, since speech impediments have no correlation with intelligence, your statement is a non sequitur.

I took speech therapy my first two years of elementary school. So I've got to agree w/ biologist here. Ego, ya know?

|12.1.06 @ 12:48PM|#

Mitch

From the study

"Our analysis revealed a main effect of race, F(1, 130) = 5.78, p < .05, [eta]2 = .04, such that African Americans (M = 22.12, SD = 4.55) scored lower on average than did Whites (M = 23.80, SD = 3.78). In addition, the analysis revealed a Race × Instructions interaction, F(2, 130) = 6.44, p < .01, [eta]2 = .09, MSE = 15.73. Consistent with our predictions, planned comparisons revealed that although the difference between African Americans and Whites under standard testing instructions replicated the typical race difference favoring Whites, F(1, 130) = 6.44, p < .05, d = 0.75, a difference that was even larger in the high threat condition, F(1, 130) = 10.22, p < .01, d = 1.00, this difference was actually reversed in the low threat condition, although the difference here was not statistically significant, F(1, 130) = 2.30, p > .10, d = -0.47. Likewise, and in contrast to the results reported by McKay et al. (2002), African Americans in the low threat condition scored significantly better than did African Americans in either the standard or the high threat conditions (ps < .05). It is especially noteworthy that African Americans in the low threat condition performed as well as Whites did in either the standard or high threat conditions. Thus, removing the relevance of the racial intelligence stereotype increased the APM scores of African American participants to essentially the same level as that of White participants in the conditions in which Whites performed their best. Adding gender of participant as a covariate in these analyses did not change any of our conclusions, and gender itself was not a significant predictor of ACT-adjusted APM scores (r = .16, p > .05; male = 1, female = 0).

Further examination revealed that these performance effects were largely due to decrements in performance accuracy (number of problems answered correctly divided by number attempted) rather than mere persistence. As with basic performance, there was a significant race main effect on accuracy (residualized within race for prior ACT scores), F(1, 130) = 8.57, p < .01, [eta]2 = .06, and a significant Race × Instructions interaction, F(1, 130) = 5.20, p < .01, [eta]2 = .07, MSE = 0.016. As shown in Table 2, African American participants were significantly less accurate than Whites in the standard and high threat conditions (ps < .05). In contrast, African American participants in the low threat condition were slightly, but not significantly, more accurate than Whites in the low threat condition, F < 1. The Race × Instructions interaction was not significant for number of problems attempted (also adjusted within race for prior ACT scores), F < 1, although African Americans overall (M = 35.0, SD = 2.01) did answer slightly more items than did Whites (M = 34.06, SD = 3.21), F(1, 130) = 3.77, p = .05, d = 0.33."

The different conditions explained...

"In the standard threat condition, participants were given instructions consistent with the published manual for the APM (Raven et al., 1998). Specifically, participants were told, "The Advanced Progressive Matrices is a measure of observation and clear thinking." The APM was referred to as a "test" several times during these instructions. Participants in the high threat condition were told, "The task you will be working on is an IQ test. Like the SAT and ACT, this test is frequently used to measure individuals' intelligence and ability." The items were referred to as an "IQ test" several times during these instructions. Finally, in the low threat condition, participants were told, "The task you will be working on is a series of puzzles. Please take these puzzles seriously. When you are finished working on the puzzles, we would like to ask you some questions about the puzzles and get your thoughts and reactions about them." At no time during the low threat instructions were the items referred to as a test; rather, items were consistently referred to as "puzzles." By combining this consistent reference to the APM items as puzzles with the indication that we desired participants' feedback about the items, we intended to remove any suggestion that the task was evaluative in nature-thus reducing the relevance of racial stereotypes about intellectual abilities. After providing these condition-specific instructions, the experimenter (a White man) provided all participants with specific instructions on how the items work."

|12.1.06 @ 1:05PM|#

Rik,

That is a nice review article...

I noticed this.

"In a recent study of 320 pairs of twins born in the 1960s and given IQ tests at age seven,Turkheimer et al. found that environmental factors have a much greater influence on childhood IQ in impoverished families relative to those in families of higher socioeconomic status. The heritability of IQ at the low end of the wealth spectrum was just 0.10.By contrast, it was 0.72 for more wealthy families, indicating that nature is more significant than nurture when socioeconomic status is high, while the reverse is true when socioeconomic status is low. That the genetic contribution to intelligence differs in different environments is a caveat against general inferences based on heritability data."

|12.1.06 @ 1:13PM|#

there's some backstory to the Turkheimer data, which isn't totally clear to me. so like everything, take it with a grain of salt.

however, the general caveat is probably warranted. extremely poor environments will surely reduce heritability. however, most estimates of heritability in the black american population find values similar to those found in the white population.

|12.1.06 @ 1:14PM|#

I don't know any statistics, but it seems like whites did better when they thought they were being evaluated, while blacks did better when they believed they were not being evaluated.

Is the stereotype threat theory that blacks do more poorly when they believe they are being evaluated because they have heard all their lives that blacks do poorly on tests, and thus have low morale? If this theory is accurate, does it describe a cyclical problem, where blacks do badly on tests because they have heard that blacks do badly on tests? How do you solve such a problem?

Also, is there a theory as to why whites seem to be slacking off when they don't think they are being tested?

|12.1.06 @ 1:16PM|#

My instinct is that the gap is all (or almost all) cultural based. That's not to say cultural bias, but upbringing. 70% of blacks are born to single-parent upbringing, and the black culture is much more anti-intellectual than others. If you're born into a family that doesn't have as much time to read to you (only one parent), doesn't value reading and even actively discourages reading as "acting white," then you're probably going to take a lot longer to read the test questions, comprehend them and then provide good answers. Hence, low IQ scores.

I do believe the IQ scores are accurate, but I don't believe that it implys a genetic disadvantage for blacks.

|12.1.06 @ 1:16PM|#

Rip

I trust that microcephalic comment was meant to be humorous.

However, the socio-ecomomic class -measured by income quintile - one was born in is a much better predictor of what class you will reach in your forties than I.Q. tests.

|12.1.06 @ 1:26PM|#

Aresen, here's the abstract from a new paper on IQ and SES:

The relationship between intelligence and socioeconomic success has been the source of numerous controversies. The present paper conducted a meta-analysis of the longitudinal studies that have investigated intelligence as a predictor of success (as measured by education, occupation, and income). In order to better evaluate the predictive power of intelligence, the paper also includes meta-analyses of parental socioeconomic status (SES) and academic performance (school grades) as predictors of success. The results demonstrate that intelligence is a powerful predictor of success but, on the whole, not an overwhelmingly better predictor than parental SES or grades. Moderator analyses showed that the relationship between intelligence and success is dependent on the age of the sample but there is little evidence of any historical trend in the relationship.

http://dx.doi.org/10.1016/j.intell.2006.09.004

|12.1.06 @ 1:42PM|#

I trust that microcephalic comment was meant to be humorous.

Actually, it was one of my lines in Defending Your Life.

Thomas Paine\'s Goiter|12.1.06 @ 1:46PM|#

TPG: if you memorized something, don't you "know" it? I'm not talking about comprehension. we're talking about the same thing.

I don't think so. You might know wh

Thomas Paine\'s Goiter|12.1.06 @ 1:47PM|#

Hmmm. I was cut off. You might know when to recall something, but you don't have to "know" it.

|12.1.06 @ 1:47PM|#

Here is my argument (if anyone wants to take me up on it). If IQ is important for producing wealth etc., and black have lower IQ's then black people will have less wealth. But when you start spreading the news and publishing study after study about how black people have lower IQ's than white people then IQ doesn't just effect a black person's wealth because it effects their ability to produce wealth, it also effects their wealth because of how people perceive them. That is, constantly talking about a race's lower IQ is not economically efficient because it places an extra unneccessary cost on the members of the race. Thus is people that argue for the existence of general intelligence (g) wouldn't talking about g all the time just interfere with g's ability to actually influence the world (so arguments that g is the most important factor in predicting sucess in this modern world also provide reason not to talk about g)? Does this make any sense to anyone but me?

On a related note, I put IQ arguments in the same category as Jared Diamond's "Guns,Germs, and steal" argument in that they're all blatant attempts to excuse, justify, or apologize for the way our social world is currently set up.
Also, I am color blind and I don't see race.

|12.1.06 @ 1:50PM|#

insert after (g): "are right then"
Always preview.

|12.1.06 @ 1:59PM|#

"The present paper conducted a meta-analysis of the longitudinal studies that have investigated intelligence as a predictor of success (as measured by education, occupation, and income). In order to better evaluate the predictive power of intelligence, the paper also includes meta-analyses of parental socioeconomic status (SES) and academic performance (school grades) as predictors of success."

Translation: "When we jiggle the data we get..."

|12.1.06 @ 2:07PM|#

Dumb people hate IQ because it confirms their stupidity.

Smart people love IQ because it confirms their superiority.

I really love IQ tests. My wife and I have our IQ tested routinely to try and prove who is smarter. Unfortunately, she tends to outscore me by 5-10 points on average...

|12.1.06 @ 2:16PM|#

Anecdotally, I went to high school in the late '80s, early '90s. There were 287 kids in my graduating class, located in a decidedly middle-class suburb with an average public school system.

By high school, everyone in the school knew who was "smart" and who was "dumb". These designations had no correlation to our grades, but did prove to be very highly predictive of SAT scores.

Now, 15 years later, IQ has proven to be a vastly better predictor of success than grades.

In the modern knowledge-worker economy, there are lots of jobs which simply require a high IQ. No amount of effort, personality, or connections will make you a talented programmer or quantitative analyst.

As for me, I hate interacting with people, I'm really lazy, I don't care about my job or making money, but I have a 150 IQ, so I make almost $200,000 a year - and I spend most of the day surfing the net. Choke on that, dummies.

|12.1.06 @ 2:38PM|#

"Translation: "When we jiggle the data we get..."

Jiggle isn't really a good description...

http://www.wilderdom.com/research/meta-analysis.html

Meta-analysis, when conducted properly, is the highest level of evidence available in science.

|12.1.06 @ 2:44PM|#

Mitch,

"Is the stereotype threat theory that blacks do more poorly when they believe they are being evaluated because they have heard all their lives that blacks do poorly on tests, and thus have low morale?"

Yes.

"Also, is there a theory as to why whites seem to be slacking off when they don't think they are being tested?"

No. There is no evidence that this occurs.

The results show this...

In the standard condition, whites do better than blacks. In the high threat condition, whites have an even bigger advantage. In the low threat condition, the difference disappears because blacks do as well as whites, and do as well as the whites did in the other two conditions. There was no evidence that whites performed worse in the low threat condition than they did in the other conditions.

|12.1.06 @ 2:58PM|#

I have a 150 IQ, so I make almost $200,000 a year - and I spend most of the day surfing the net. Choke on that, dummies.

You damn smart people, you all think you're so smart!

|12.1.06 @ 4:28PM|#

MainstreamMan,

The article seems to say that whites did worse under "low threat conditions" on page 984, left column.

Overall, the data in the present study were consistent with predictions derived from stereotype threat theory. Somewhat surprisingly, though, Whites in the low threat condition actually performed worse than Whites in the other conditions. Although not predicted, this trend is consistent with results reported by McKay et al. (2002), who found a somewhat smaller difference in the same
direction among Whites in the nondiagnostic compared to the diagnostic condition. Whether this difference represents a decrement
among White participants in the low threat (or nondiagnostic) condition (as McKay et al. argued) or an increment in the standard and high threat (or diagnostic) conditions is a matter for speculation. However, the latter interpretation is consistent with a
meta-analysis by Walton and Cohen (2003) on "stereotype lift" effects among positively stereotyped groups taking ability diagnostic
tests.

|12.1.06 @ 6:20PM|#

Mitch,

Yep. Missed that. Thanks for the heads up.

|12.1.06 @ 6:31PM|#

A look at table two and their statistical analysis, however, makes it seem like the "trend" was not statistically significant. I wouldn't make too much of it.

M|12.1.06 @ 8:25PM|#

There are similar studies showing that "stereotype threat" hinders women's performance in math and science.

|12.1.06 @ 9:45PM|#

And what of the correlation between small or short heads and I.Q.? Anything to that?

|12.2.06 @ 4:04AM|#

...Minorities like Asians and Jews score significantly better on IQ tests...

Does that apply to converts? I'm normally an atheist but I can be bought...

|12.3.06 @ 6:40PM|#

Picking up on Oomigmac's post- I've consistently scored in the 99th percentile of every standardized exam I've taken. I've never taken a test prep or otherwise prepared for any of them. My grades were never great though, just pretty good. People who meet me often tell me that I'm smart within minutes of meeting me. I'm 27 and make 500k a year.

|12.4.06 @ 9:31AM|#

Too bad Oomigmac's sense of humor doesn't come along with all that brain power.

|12.4.06 @ 11:50AM|#

Turkel...

We are all so impressed. You are the envy of the other 99%. We are all honored by your intelligent comments on the topic. Knowing that you were able to ace those standardized tests and get a good job moves this discussion into a whole new realm of significance.

What kind of car do you drive?