That's interesting, but I think there are also studies that show childhood IQ tests don't correlate very well to adolescent or adult IQ tests - which, as others studies have shown, are tests that do correlate well to success/happiness/etc. over lifetimes.
This study would be a lot more interesting if it followed its sample into adulthood and compared IQ scores over time - it very well may do that, it's just not clear from the article that there is very much meaning here when put into context with other studies on childhood IQ.
Childhood IQ tests get complicated by the fact that a lot of what you measure is which children hit growth spurts already, which come with attendant intellectual improvements.
But I have had a psychologist who specialized in the field say that the best predictor of adult IQ was receptive vocabulary. Meaning how many words does the child understand? Understanding words, even words you don't know how to use, predicts future intellectual development because it says who has the foundation.
Adult vocabulary is a strong predictor of adult IQ just as child vocabulary is, but I wouldn't recommend studying vocabulary to get smarter. Being "a predictor" says nothing about being a cause; smarter kids know more words because they're smarter, but the "predictor" relationship is established at the point of "smarter kids know more words".
I am informed (by a Chinese teenager, so possibly not perfectly reliably) that vocabulary size isn't considered a concept in China -- there are words that everyone is expected to know, technical vocabulary, and words that no one is expected to know (by way of example, I use the word "vacillate" in my day-to-day casual speech, but that's unusual, and many native english speakers don't know what it means. That situation is not supposed to be possible in China).
For purposes of my point, the truth of the assertion isn't really relevant. Such circumstances, obviously, mean that vocabulary can't be a predictor of IQ after the age at which it's all been learned. Do you imagine that IQ differences would disappear along with the predictive value of vocabulary size?
You missed the point. The psychologist had specialized in child development. His claim was that receptive vocabulary in grade school children was the single best predictor that was known for their IQ and tests scores in high school and presumably beyond.
Studying vocabulary as an adult is probably not going to get you very far. But having been exposed to a lot of vocabulary when you're young seems to be a good thing.
(He was telling this at the same time that he was telling me that my 7 year old son had the receptive vocabulary of an average 13 year old. So I was happy to hear it.)
> His claim was that receptive vocabulary in grade school children was the single best predictor that was known for their IQ and tests scores in high school and presumably beyond.
This isn't true. For example, IQ as a 20 year old is a better predictor of IQ in high school than receptive vocabulary in grade school is. It happens that it's hard to observe the IQ at age 20 of a child who isn't 20 yet, but that doesn't change the strength of the predictor.
> But having been exposed to a lot of vocabulary when you're young seems to be a good thing.
You provide no support for this other than the fact that a large vocabulary at a young age is indicative of a high IQ later. However, a large vocabulary later is also indicative of a high IQ later. Applying the same logic, you should conclude that being exposed to a lot of vocabulary when you're old is just as good (if not better!).
If you don't think studying vocabulary as an adult will get you very far, why do you think studying it as a child is different?
This isn't true. For example, IQ as a 20 year old is a better predictor of IQ in high school than receptive vocabulary in grade school is. It happens that it's hard to observe the IQ at age 20 of a child who isn't 20 yet, but that doesn't change the strength of the predictor.
A predictor is something that you can measure and make predictions from in advance. Therefore by definition the eventual IQ at age 20 is not a predictor of future IQ for grade school children.
Now can we dispense with the semantic games?
> But having been exposed to a lot of vocabulary when you're young seems to be a good thing.
You provide no support for this other than the fact that a large vocabulary at a young age is indicative of a high IQ later. However, a large vocabulary later is also indicative of a high IQ later. Applying the same logic, you should conclude that being exposed to a lot of vocabulary when you're old is just as good (if not better!).
Not indicative, predictive.
Receptive vocabulary is part of IQ. So of course having a large receptive vocabulary helps your IQ. But children with a large receptive vocabulary when young tend to have future increases in other mental abilities. By contrast children who show high abilities in other areas when young do not show the same improvement.
The theory that I was told is that children who can understand complex verbal things find it easier to learn from our education system. And children can't learn to use complex language without first understanding it.
If you don't think studying vocabulary as an adult will get you very far, why do you think studying it as a child is different?
The research on development that I've encountered indicate that there are specific developmental periods where we are particularly receptive, and where our abilities tend to increase suddenly. Starting with a large receptive vocabulary seems to position you well to make the most of these.
When you're older, studying vocabulary is unlikely to be bad for you. But you don't have the same developmental spurts ahead to try to maximize. Furthermore vocabulary is less likely to be a barrier for adults than children.
For example my son right now loves ants. He is learning things about ants that other children his age would have trouble with because he understands words they don't. But he doesn't have a better vocabulary than most adults. Any literate adult who wants to learn what he is learning about ants can simply pick up material on ants and read it.
The study was primarily looking at language acquisition, not IQ. The researchers themselves did find that language mediated IQ somewhat, but IIRC the effects weren't especially noteworthy. I haven't read the book in a while though, so I can't remember the exact details.
This study would be a lot more interesting if it followed its sample into adulthood and compared IQ scores over time - it very well may do that, it's just not clear from the article that there is very much meaning here when put into context with other studies on childhood IQ.