Average IQ scores seem to have been falling and population ageing may be why

Re:Average IQ scores seem to have been falling and populatio... by subroutine on Friday September 29, 2017 @06:26AM (#15364092)

It seems like with just a bit more effort the authors could have made a stronger case for their theory that aging is significantly impacting IQ scores by comparing IQ scores among people of the same age (e.g. 20-30 year olds) from decade to decade. They could also look at how IQ changes over a lifespan; there must be some within-subject data available where the same people took an IQ test when they were <30 then again when >60.

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Re:Average IQ scores seem to have been falling and populatio... by Idontknowmyuser on Friday September 29, 2017 @07:30AM (#15364366)

You only do enough research to get the p values just right so you can publish. Scientists are not rewarded for more investigations that might weaken their theory.

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Re:Average IQ scores seem to have been falling and populatio... by fortythirteen on Friday September 29, 2017 @11:05AM (#15365913)

And then a lazy journalist publishes a headline inflating the results, and the average person unquestioningly believes it, lowering our collective IQ.

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Re:Average IQ scores seem to have been falling and populatio... by iTokio on Friday September 29, 2017 @10:45AM (#15365726)

P-hacking or how to sell your scientist soul.

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Re:Average IQ scores seem to have been falling and populatio... by Alex3917 on Friday September 29, 2017 @09:00AM (#15364817)

> They could also look at how IQ changes over a lifespan

It doesn’t because it’s a bell curve. You literally can’t figure out your score until you already know the distribution.

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Re:Average IQ scores seem to have been falling and populatio... by pizza on Friday September 29, 2017 @10:59AM (#15365868)

The distribution of an individual's IQ (as a quantile in the group's aggregate, normalized IQ distribution) is not a dirac delta. It's not constant over a lifespan at one location.

I think there would be significant noticeable losses in IQ due to social factors, too, and to a much greater extent than most people would appear to believe when they talk about the heredity of IQ but then think that means IQ determinism..

For example someone could test at 115 IQ, become homeless, then have something much closer to ~100. (Do not use "but someone that smart would never become..." as a cop-out..)

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Re:Average IQ scores seem to have been falling and populatio... by subroutine on Friday September 29, 2017 @09:56AM (#15365263)

Nonsense. If I administer an IQ test to 1000 people in their 20s, and then retested them in their 60s, I'd be performing a classic within-subject test, where I could easily assess whether test performance increases, decreases, or doesn't significantly change.

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Re:Average IQ scores seem to have been falling and populatio... by Alex3917 on Friday September 29, 2017 @02:26PM (#15367764)

My point was that let's say all 1,000 people in their 20s got every question correct, and then you retested them in their 60s and they all got every question wrong. Assuming the sample was representative of the overall population, the group's average IQ would have remained constant at 100.

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Re:Average IQ scores seem to have been falling and populatio... by KGIII on Friday September 29, 2017 @06:48PM (#15369920)

That's not quite accurate. The score adjustments are periodic, not constant. The 100 average is from some years ago, and will be adjusted some time in the future. It is not constantly changing to reflect current scores.

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Re:Average IQ scores seem to have been falling and populatio... by SketchySeaBeast on Friday September 29, 2017 @10:22AM (#15365498)

Absolutely, they IQ test and the relative results are constantly changing according to the population's performance, but if you take a snapshot of the test by using the original test and scoring rubric, you can determine if your IQ changed from your 30's to your 60's in relation to the original distribution.

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Re:Average IQ scores seem to have been falling and populatio... by jules on Friday September 29, 2017 @12:00PM (#15366441)

IQ is defined as relative to your age group, but absolute IQ test scores start to decline in your 40s at a rate of approximately 6 points per decade.

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