What is Flynn effect? (IQ Score, Psychology, Graph)

Flynn Effect Explanation

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. Also, it’s a worldwide phenomenon that the world population is getting brighter 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 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. There are many different types of intelligence.

An IQ score looks at a few areas that we believe are important to this intelligence construct. They’re an essential part of intelligence. IQ is a standard score 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 with biological reasons. For instance, we could look at Asian students routinely outscoring their white American math performance counterparts.

We might consider that this could be genetic. Maybe there’s some genetic difference between the races 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 plays a role.

Maybe there are different cultural pressures on students and other expectations regarding their math performance. It 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.

Regarding their average performance today, they’d probably score about a hundred and ten, 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 coined by Richard Herrnstein and Charles Murray in the bell curve. Moreover, it refers to research by James Flynn on the rise in IQ over time. Let’s look at the Flynn effect graph.

Flynn effect graph

So Flynn demonstrated that the average IQ seems to have risen about 3 points per decade over the past few decades. 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 more complicated, and your performance is only compared to 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 an average IQ of 70 or below a few generations ago was everybody.

That doesn’t seem to make much sense. If we went back a few hundred years, it would mean that everybody had an intellectual disability. 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 is some advantage to a higher IQ. That’s causing us to have this increase in IQ over time. It would be a 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 current.

Evolution occurs over extended periods and doesn’t happen in a decade. So we can probably rule out that our genes are changing this quickly. We’re left with some environmental factors if we rule out genetic factors. Now we’ll consider what these environmental factors might explain this dramatic rise in IQ.

Factors that affect 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.

1. Nutrition

Nutrition improves in certain areas where the average IQ score increases. It is not on an individual basis. You will have fewer sorting or pulled-down scores if fewer people are malnourished.

So when we have fewer underweight children, we’re not going to have as many lower scores. If children are malnourished, they don’t have adequate nutrition, which will hinder their development. 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 develop, their scores will be pushed up, increasing the average score.

We can also think about this, not only overall nutrition. You might think that wouldn’t matter much, but introducing iodine into table salt has been estimated to be responsible for several points of average IQ increase. 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. That’s not happening anymore. They will reach their potential, which means they will have higher IQ scores. That’s also going to help to push the average up.

2. Education

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, even a few decades ago or a hundred years ago, their school spending was much higher.

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 attend college and earn even higher degrees.

So this could be related to a rising in IQ scores. It’s not that people spend more time in school. It’s that the type of education has also changed. Flynn has argued that we do much more abstract reasoning now than we did 30 or 40 years ago.

So the type of education has changed. They involve abstract reasoning hypothetical situations and working with new problems 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 the limit

Another thing is that this effect seems 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 we’re reaching the limits of improving nutrition and educational opportunities for students.

In the past, things were pretty bad for many people regarding their access to nutrition or education. 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. 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 hard to imagine. But it’s the neurological hardwiring that occurs in those first four years. In those first four years, you also learn the rudiments of language. You have a relatively small vocabulary, but you realize there are verbs, nouns, and how to put sentences together.

More Article:


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.

Julia Rose

My name is Julia Rose. I'm a registered clinical therapist, researcher, and coach. I'm the author of this blog. There are also two authors: Dr. Monica Ciagne, a registered psychologist and motivational coach, and Douglas Jones, a university lecturer & science researcher. I would love to hear your opinion, question, suggestions, please let me know. We will try to help you.

Leave a Reply

Your email address will not be published. Required fields are marked *