In 1970 a most remarkable study was done. 35 Australian Aboriginal kids (57% female) raised by white families in Adelaide, South Australia since they were 1.5-years-old (on average), were intelligence tested. The kids ranged in age from five to 14 and ranged in ancestry from 100% Australoid to only 13% Australoid (about 58% on average). Unlike the Minnesota transracial adoption study where the adoptive parents were college educated, the “socio-economic status of the adopting families exhibited no obvious characteristics: they appeared to be representative of a wide cross-section of the South Australian population.”
This is good because it lets us see how a different race would score if reared in the typical white environment.
One of the tests given was the highly g loaded Peabody Picture Vocabulary test where the examiner says a word, and the subject points to one of several pictures that best represents that word. Below we see a chart comparing the mixed race adopted Adelaide Australoids to both white norms (standard scores from the test manual) and presumably unmixed and non-adopted Australoids tested at Hermannsburg Mission.
The chart above suggests that unmixed, unadopted Australoids at age nine, 10, and 11 would have obtained raw scores on the PPVT (form A) of 37, 42, and 42. Using table 2 below I equate these to IQs of 44, 51, and 45, respectively (U.S. white norms). If these IQs sound absurdly low, keep in mind this is a vocabulary test and many of the unmixed unadopted Australoids perhaps did not speak English as their primary language.
Meanwhile at ages five, nine, 10 and 11, the mixed adopted Australoids have raw scores of about 44, 63, 65 and 95, corresponding to IQs of 88, 86, 85 and 118.
On average the mixed adopted Australoids probably averaged verbal IQs of 94 (6 points below the white mean of the U.S., the U.K. and Australia) and considering they’re only 58% Australoid on average, unmixed adopted Australoids would likely have scored 90 (6 points below white mean/0.58 = 10 points below the white mean).
Conclusion
When raised in their own communities, unmixed Australoids seem to average about IQ 47 on English Picture Vocabulary (3.53 standard deviations below the white mean). But when raised in white homes they likely average IQ 90 (0.66 SD below the white mean). Thus this racial gap appears at most, only 19% genetic.
Challenges
Were the norms from the original PPVT valid for English speaking communities in 1970 Australia?
Given that the original PPVT was normed on several thousand white kids in and around Nashville, Tennessee in 1959, one might question its validity in 1970 Australia. A 1972 paper by L. J. Taylor , P. R. De Lacey & B. Nurcombe specifically set out to answer this question. They tested 60 Australian kids (mostly using form B) from age 4 to 10. Aside from age 4 where they included a lot of mixed Australoids in the sample, the average IQ at every age ranged from 91 to 112 or about 104 on average. So if anything the 1959 white norms from Nashville were perhaps 4 points too generous for Australians in the early 1970s, though even this slight inflation might be explained by the fact that the study translated three words on the test from American English to Australian English.
Did the IQs of the mixed race adopted kids decline in adulthood?
There was no follow-up study so we don’t how the adopted kids would have scored in adulthood, but in the Minnesota transracial adoption study, the IQs of adopted kids dropped between five to 13 points from age seven to 17. This drop was likely exaggerated by old norms in an at least one of the test sessions (and poor attempts to correct for the Flynn Effect), but to the extent that it was real, it was likely caused by the adoptive parents being upper-middle class. By contrast, in this study, the adoptive parents were more representative of the white population so the adoptees enjoyed the same environment as the average white kid, not benefitting from an upper class IQ boost that quickly fades.
[Update December 12, 2021: Thanks to a correction from an alert reader, some numbers in this article were substantially revised]
Pumpkin Person 
Reposting this from the previous comment section because it’s relevant:
Pepe, here’s something that you as an HBD nerd might find interesting. I was at the optometrist the other day, where they poked my eye with a tiny brush-like apparatus to measure eye pressure. I kept reflexively tearing up and pulling away, as most people do. The optometrist said that Australian Aboriginals don’t have that reflex! Strange.
yes i read that the first time and it sounds disgusting. Hope my optometrist never tries that on me.
I don’t know why. Maybe they thought I could have glaucoma? I didn’t, but I did have a posterior vitreous detachment (floater), which is usually associated with people in their forties or older, but is also more common in people with serious myopia (nearsightedness), which I have. I suppose glaucoma could be positively correlated with myopia too, hence the need to test for it.
Jordan Peterson had similar eye problems that went away when he converted to a caveman diet so he says
There’s a huge peak in the graph at age 12 but table 2 provided no norms for this age which is probably for the best since such an outlier would skew the sample.
I think you mean age 11.
If the children were adopted at age 1.5, could that have reduced their English performance compared to a child adopted at birth? Children are already developing language by then.
I think you mean age 11.
you’re right you do have eye problems 🙂
If the children were adopted at age 1.5, could that have reduced their English performance compared to a child adopted at birth? Children are already developing language by then.
I doubt it but it’s a good question. They should have correlated age of adoption with scores to rule out that possibility.
I copied the image into MS Paint and inserted a straight line from the peak of the graph to the x-axis. It looks like the spike is at 11.5 based on that
Post it.
OMG you’re right! I will revise the article accordingly.
Okay I updated the article to reflect your correction and what a difference it made. Their estimated genetic verbal IQ went from 76 to 90!
It looks more like 11.5 or 11.6 to me, actually. So we were both right.
Looks like all the aboriginal ages are a bit off compared to the white ages.
“corresponding to IQs of 88, 86, 85”
The abo-white gap in the graph looks about constant for those years yes, but standard deviations are increasing which should translate into a lower IQ gap for the same test score gap, no?
“Meanwhile at ages five, nine, 10 and 11, the mixed adopted Australoids have raw scores of about 44, 63, 65 and 95”
More like ages 5.5, 7.5, 9.5 and 11.5.
The score don’t make sense either. White 5 year olds have a score of 55 according to the table, but aboriginal 5.5 year olds who are only slightly behind in the graph you put at 44? And an 11 point difference with a 7.5 SD would translate into an IQ of 78, not 88.
An 11.67 point difference is a Z score of -1.55 which would roughly equates to an IQ of 77 if those were the test’s norms (mean IQ 100 SD 15).
but I don’t have those stats so I’m comparing them to another group of white kids.
If you look at the two rows underneath, you see these white 5-year-old have an average IQ of 109.96 and an SD of 13.85 on the test norms so a Z score of -1.55 on their distribution is about IQ 88 on the test norms.
I see, thanks.
“mixed adopted Australoids have raw scores of about 44, 63, 65 and 95”
By imposing a gridline on the graph one can get more accurate estimates.
Real numbers are more like 46, 57, 67.5 and 95.
So instead of 9 year olds scoring 63, they’re actually 7.5 year olds scoring 57?
So instead of 9 year olds scoring 63, they’re actually 7.5 year olds scoring 57?
I only calculated IQs for ages 5, 9, 10 & 11 because those are the ages I have norms for (table 2)
I’m confused. For aboriginal test scores did you use the numbers at the triangles closest to those ages, or did you extrapolate in straight lines from those triangles to the correct ages?
The 5-year old and 9-year old aboriginal scores you estimate look like such extrapolation, but not the older estimates.
I’m confused. For aboriginal test scores did you use the numbers at the triangles closest to those ages, or did you extrapolate in straight lines from those triangles to the correct ages?
The former was my intention but it’s likely I made a few minor mistakes as interpreting these graphs gets quite tedious.
Is the tantrum over yet?
Why do you put so much stock in kids IQ scores. For something like a picture vocab test it means all the world whether they are raised by whites or raised in the scrub by aborigines. The test is too culture loaded.
I would prefer they were tested as adults but this is the only study of australoids adopted by whites. It is said that by the age of 10, IQ is so stable that it makes no difference if you’re tested as a kid or as an adult but that’s probably an overstatement..
But the test is stupid. I’m exaggerating a bit but its like testing people for their knowledge of Bible verses and comparing christian adopters with aborigine adopters.
Well it’s not the only test they took and in the rest of the series I will discuss the others. I understand how you feel. David Wechsler himself thought so little of vocabulary that it was originally only used as an alternate test (if one of the main tests was spoiled). To his surprise vocabulary turned out to be one of the best tests in the entire battery, showing an impressive correlation with overall IQ.
The reason vocabulary is such a good measure of IQ is we learn new words not by memorizing word lists or looking words up in the dictionary, but by inferring the meaning of a word from the context they’re used in and that’s a process that requires subtlety and abstract reasoning. So if Australoids raised in white homes have smaller vocabularies than whites raised in white homes, it suggests a genetic difference.
Australian Aboriginals are the master race fools!