Can somebody explain the Flynn effect for me? As I understand it, a psychologist (Dr. Flynn!) found that IQs jump a large amount between generations within the same family. I think the story I was told was that military IQ tests of fathers and sons in nations with required service showed a very large jump between the generations (sons > dads). The jump was larger than expected if genes played a very large role, so it was argued that this pointed towards the ball being back in nurture’s court.
Obviously, the issue is an interaction, but for the population at large, and assuming the studies ruled out selection bias (tell if you know they didn’t, however), could this only be explained by nuture, not nature?
In anycase, I’d like to hear what the effect is, if I got it wrong or so simple as to be wrong-ish.
The Flynn Effect is the name given to the observation that performance on IQ tests has been steadily improving since they were first instituted, in every country for which IQ data exists.
IQ tests are normalized so that the average score is always 100. If this wasn’t done, IQ scores would be higher in every generation – the increase ranges from 5 to 25 points per generation. In the U.S., I believe the increase was around 20 points, so a score of 100 would have been equivalent to a score of 120 a few decades ago.
Google “Flynn Effect”, and you’ll find plenty of sites discussing the phenomenon.
The usual figure given for the Flynn effect is that I.Q. rises by about 3 points for every decade. The use of I.Q. tests on a large scale is about 80 years old, so if we look back as far as we have records of I.Q. testing, the increase would be about 24 points. The effect was discovered by a New Zealand political scientist named James R. Flynn. I believe that his first paper on it was published in 1984. The earliest large-scale use of I.Q. tests were in the U.S. military, which is why Flynn used them for his early research. The effect has been found in many other long-term uses of I.Q. tests.
The problem in answering your question is that nobody completely understands what causes the Flynn effect. Clearly, the human race hasn’t evolved so much over the past 80 years that the average I.Q. has risen by 24 points. But if it’s the environment that has changed so much as that, what part of the environment? One of the obvious guesses was that nutrition and the prevention and treatment of disease has improved so much that it’s caused the increase. That’s not going to work either, though. Even if you assume that everyone 80 years ago was on the edge of starvation, that wouldn’t be a big enough change. Do a Google on “Flynn effect” and you’ll find some papers speculating on various possibilities and showing why they aren’t important enough to explain the increase in measured I.Q. I think that what the Flynn effect shows is that we don’t really understand what it is that we’re measuring when we give people I.Q. tests.
I would introduce the concept of “information” to the nature/nurture debate. I suspect that one of the main ingredients in rising scores has to do with the much greater availability of information as we “progress.”
Since the IQ tests are after those components of our intelligence that respond to tests, and since the tests are based (to some extent) on information that the testee has acquired and processed, the more information available to the testee, the better chance the testee has of processing it.
I suspect the Nurture aspect would be more involved in more information, but I can imagine how genetics may have helped move the information explosion along, too.
Its always Nature and Nurture… both play roles… the issue is how much is one contributes.
One question thou... arent recruiters in general more demanding with possible new soldiers than before ? 80 years ago you americans had mandatory military service... now you have a volunteer army. 80 years ago you didnt need to use technology beyond guns for a regular GI... nowdays they might have to deal with GPS, computers and other tech....
Just my idea... the US soldier now has way bigger demands on him than even 15-20 years ago. That might schew a bit the Flynn effect.
Do remember thou that we live in the so called Age of Information… and even the dumbest now use internet and have way more acess to information and learning. So IQ as a test should naturally measure differently from the past.
Rashak: if IQ measures something innate, than would information access matter? (That question also relates to Zeldar’s reponse.) Also, I assume that the people studying the Flynn Effect and find it real have looked into the selection bias issues that you raise (ie, that only better people now are in the US military).
Wagner: the issue that the Flynn Effect points out that we are not sure what IQ tests measure is a possibility I hadn’t thought. Thanks!
Another thing to remember is that we’re dealing with averages. A high school graduate in 2003 might not be any smarter than a high school graduate in 1923, but increasing public education has ensured that a higher percentage of the population are high school graduates in 2003.
The I.Q. testers are careful enough that they wouldn’t compare an I.Q. test given to 90% of the population at one time to one given to 10% of the population at a later time. They are only using cases where the population tested is reasonably comparable. And the Flynn effect has been tested in many different populations (only a few of which involved the military) in many different countries.
Here’s some things I came up with by Googling on “Flynn effect”:
Seriously, Google on “Flynn effect” and you will find dozens of interesting references. This subject isn’t even understood by psychologists who are experts on I.Q. testing, so there’s no way that you’re going to find the answers to your questions by asking us. Many of the websites that you’ll find online have lists of articles and books on the subject. Read some of them and you might find out more about the subject, but there’s simply no way to answer your question adequately in a thread. There’s no general agreement about the subject.
IQ test results only measure the ability of the participant to do well on IQ tests. This skill can be improved with practice.
The modern lifestyle acquaints people with many of the concepts and prepares people with many of the skills that would serve as advantages to the IQ test taker. The wider availability of science fiction in its many forms invites people to hone their spatial imagination skills. The wider availability of consumer goods and the formation and gradual spreading of a consumer culture, compels people to spend more money more often on a variety of things, honing book-keeping skills. The fusion of many cultures (as third-world citizens emigrate more and more often to western countries) hones people’s pattern recognition skills – anything from ethnic prints on clothing to foreign art.
In short, modern culture prepares more capable IQ test takers.
I do not have a cite on this, but I know from anecdotal experience, from myself and many of my friends, that the hypothesis has potential and is worth investigating. The hypothesis is that, simply, if you practice skills that are usually tested on IQ tests, you will do better and better at IQ tests.
I took a paper that Professor Flynn taught a first-year paper in Political Studies, but hadn’t heard of his more famous work until recently. He’s a really nice guy and a very good lecturer.
It is also true that the concept of IQ testing has permeated society such that people have likely taken hours and hours worth of such tests by the time they reach young adult hood.