Flynn came up with the idea and observed that IQ scores inflate at a rate of about three points per decade. It is referred to as the Flynn effect. And it’s a worldwide phenomenon that the world population is getting brighter and at a rate of about three points per decade. The belief is that the three-point increase per decade has been associated with improved and more ubiquitous media to a large extent.
According to the Flynn effect, the average IQ has risen about 3 points per decade over the past few decades. To understand IQ, we have to look quickly at the concept of intelligence and the Flynn effect. In theory, an IQ score is a measure of intelligence. However, intelligence is a very complex construct. And there are many different types of intelligence.
An IQ score looks at just a few areas that we believe are important to this intelligence construct. They’re an essential part of intelligence. IQ is a standard score that is produced by psychometric instruments designed to measure intelligence.
What is Flynn effect?
Flynn’s effect shows IQ scores have been increasing across generations across the general population by about three points per decade. There are environmental explanations or interactions of biological reasons. For instance, we could look at something like Asian students routinely outscore their white American math performance counterparts.
We might consider that this could be genetic. Maybe there’s some genetic difference between the races that are accounting for this performance gap. But when we consider that Asian students spend an estimated 30% more class and homework time on math, we might think that the environment is playing a role.
Maybe there are different cultural pressures on students and other expectations in terms of their math performance. This is at least partially explaining this difference in performance. We can also think about differences in performance to think about differences over time rather than compare people.
In terms of their average performance today, they’d probably score about a hundred and ten, let’s say different races. We could think about overall populations compared to populations in the past. So this brings us to what’s called the Flynn effect. It is a term that was coined by Richard Herrnstein and Charles Murray in the bell curve. And it refers to research by James Flynn on the rise in IQ over time. Let’s look at the Flynn effect graph.
So Flynn demonstrated that the average IQ seems to have risen about 3 points per decade over the past few decades. Now the average IQ score is still going to be a hundred. But the tests are constantly rescaled. It means the tests have gotten a little harder and that your performance is only compared to people today.
For instance, if you had a group of people who scored a hundred on a test today, they’d probably score about a hundred and ten if they were to take a task from 30 or 40 years ago. If we extrapolate from this, we start to wonder that everybody with the average IQ 70 or below just a few generations ago was everybody.
That doesn’t seem to make much sense. I mean, if we went back a few hundred years, it would mean that you know everybody had an intellectual disability. And that’s probably not likely to be the case. So what’s going on here, and how is this happening? One thing we can consider is that maybe there’s natural selection occurring.
There’s some sort of advantage for a higher IQ. And that’s causing us to have this increase in IQ over time. It would be a sort of genetic explanation. But when we look at this, it doesn’t make any sense because it’s happening far too quickly for selection to be a current.
Evolution occurs over much more extended periods doesn’t happen in a decade. So we can probably rule out that our genes are changing this quickly. If we rule out genetic factors, then we’re left with some environmental factors. Now we’ll consider what these environmental factors might be that could explain this dramatic rise in IQ.
Factors that affects on IQ score & Flynn effect
The IQ score, in theory, tells us something about how intelligent an individual is. Intelligence is only one measure of how well somebody could do at a particular type of job.
- An IQ score has a mean of 100, and the standard deviation for an IQ test is 15.
- About 68% of the population will have an IQ score between 85 and 115.
Because 85 and 115 represent one standard deviation below the mean of 100 and one standard deviations above the mean. So over two-thirds of people have an IQ in that 30 point range of 85 to 115.
Nutrition improves in certain areas that the average IQ score tends to go up. It is not on an individual basis. If fewer people are malnourished, you will have fewer scores that are sorting or pulled down. So when we have fewer underweight children, we’re not going to have as many of those lower scores. If children are malnourished, they don’t have adequate nutrition, which will hinder their development. And they’re probably not going to reach their fullest genetic potential for IQ.
So we imagine everybody has some genetic potential for IQ, but if you don’t get adequate nutrition, you will not reach that. If we improve nutrition for those children as they’re developing, their scores will be pushed up, which will also push up the average score.
We can also think about this, not just in terms of overall nutrition. You might think that wouldn’t seem to matter much, but introducing iodine into table salt has been estimated to be responsible for several points of average IQ increase. And the reason for that is that it prevents iodine deficiency disorder. An iodine deficiency disorder causes cognitive impairments and can lead to intellectual disability.
In the past, they didn’t have iodine in their diet. They developed idd, and their IQ score was stunted. And now that’s not happening anymore. They’re going to reach their potential, which means they will have higher IQ scores. That’s also going to help to push the average up.
We can also consider education as a broad environmental factor related to IQ. We might notice that people spend a lot more time in school than they used to in the past. So if we looked even just a few decades ago or look a hundred years ago, their school spending is much higher. So if we look at the percentage of the population that graduated from high school, even you know 50 or 60 years ago, it’s much lower than it is today. Then we consider how many people go to college and then earn even higher degrees.
So this could be related to a rising in IQ scores. And it’s not just that people spend more time in school. It’s that the type of education has also changed. Flynn has argued that we do a lot more abstract reasoning now than we did even just 30 or 40 years ago.
So the type of education has changed. They involve abstract reasoning hypothetical situations working with new problems that you haven’t worked with before. Your grandparents weren’t doing as much abstract reasoning when they were kids in school then kids are doing at school now. So this might also explain this rise in average IQ.
3. Reaching limit
Another thing is that this effect seems to be slow, and perhaps it’s coming to an end. Maybe IQ won’t continue to rise so much in the coming decades. So if the effect has been slowing, this suggests that we’re reaching the limits of improvements in nutrition and educational opportunities for students.
In the past, things were pretty bad for many people regarding their access to nutrition or education. And we’re changing that very dramatically. We’re lifting people out of poverty at an unprecedented rate. Maybe there’s going to be a limit. And maybe we’re already approaching in terms of people who were previously holding down the average.
If you look at dumb human development, fifty percent of your adult intelligence has been developed by each, for that’s kind of hard to imagine. But it’s the neurological hardwiring that occurs in those first four years. And in those first four years, you also learn the rudiments of language. You have a relatively small vocabulary, but you realize that there are verbs, nouns, and how to put sentences together.
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Baker, David P.; Eslinger, Paul J.; “The cognitive impact of the education revolution: A possible cause of the Flynn Effect on population IQ.” Intelligence.
Flynn, James. “Requiem for nutrition as the cause of IQ gains: Raven’s gains in Britain. Economics and Human Biology.
Teasdale, Thomas W; Owen, David. “A long-term rise and recent decline in intelligence test performance: The Flynn Effect in reverse.” Personality and Individual Differences.