A new study has come out in the journal Intelligence suggesting that the average Western IQ has actually declined by 14 points since the Victorian Era. The study was based on the results of 14 intelligence studies conducted between 1884 and 2004 — which showed a slowing of reaction times to a visual prompt. The participants in early studies were able to respond much more quickly than modern test subjects — with an average of 194 milliseconds compared to today’s 275 milliseconds.
The authors of the study point to all sorts of reasons for this drop in intelligence, in particular pointing out that women with high IQs tend to have fewer children. The suggestion is that smart people have somehow started to weed themselves out of the gene pool over the past century and that we’re slowly seeing the population become dumber and dumber.
There’s just one problem with this research: mental processing speed doesn’t actually have anything to do with how smart you are. It just means you respond to things quickly.
Gifted educators have known this for years — and it turns out, the more intelligent a child is, the more likely that they’ll show a significant gap between their verbal reasoning abilities and their mental processing speed. The results become even less relevant when the test is measuring random information, instead of asking a child to solve a problem.
In fact, lifelong gifted education advocate Dr. Linda Silverman goes so far as to say in one report on the challenges of IQ testing for highly intelligent children:
A Full Scale IQ score that averages gifted reasoning and average processing skills fails to identify either the giftedness or the relative weaknesses. Test authors have wrongly assumed that gifted children are fast processors. Some are very quick; others are reflective or perfectionistic, slowing their speed. Gifted children also show a preference for meaningful test materials, and may not perform well on short-term memory tests or other tasks that utilize non-meaningful material. They usually perform so much better with meaningful material that their scores with non-meaningful material are difficult to interpret.
She goes on to note that a majority of gifted students she’s tested — 60% — score much lower on processing speed than on verbal reasoning. These students have a gap so high in the different scores that are averaged to determine their IQ that the final score is actually meaningless (and usually a serious underestimate of their abilities).
Even the publishers of these tests admit this is a problem — and they’ve provided alternate methods for determining a child’s true intelligence in cases where the processing speed gap makes the IQ score meaningless.
So what does this new study actually mean? Without detailed testing of the average reasoning and verbal abilities of modern and Victorian populations…not much.
It just means we react a little more slowly to visual information. That’s definitely a shift that requires a little more careful study, but it doesn’t mean we’re necessarily a stupider society than we were 100 years ago.
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