Received wisdom

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Received wisdom


Average IQ is falling in Britain and beyond, explains Philip Hunter

Back when Britain was brainy: applicants for the Mensa exam gather at the Russell Hotel in 1961

Intelligence quotients (IQs) have risen in developed nations for almost a century. This phenomenon, named the “Flynn effect” after the New Zealand intelligence researcher James Flynn, was first identified in 1984 in the United States. It has been found to occur in all developed nations, and some others as well. The received wisdom became: IQs always go up. But this trend seems to be stopping and even reversing in some countries, research in Britain, Denmark and Norway has shown. It is discomfiting to find intelligence in decline. There is a strong association between a nation’s IQ, its prosperity and health.

IQ testing is contentious and regarded by some as a crude indicator of ability or potential. When comparing nations, measured average IQ tends to be affected by class, nutrition, and cultural factors including education. There is also disagreement over the influences of nature and nurture.

IQs are collated such that the average test score is 100. The standard deviation—a statistical measure of the variation within a group—is set at 15. This means that if you score 115, you are one standard deviation from the mean; 130, two standard deviations, and so on. The Flynn effect is determined by asking subjects to sit old IQ tests. The finding has been that the average score of groups who take older tests is more than 100, a disparity that suggests rising average intelligence. The rate of increase varies between nations, but on average, IQ scores have risen by three points per decade.

But in Britain, research has found a reversal of this trend. This has also been the case in other nations, including Norway and Denmark (research is not extensive, but the implication is that declines may be occurring more widely). A study in 2009 led by James Flynn himself and published in Economics & Human Biology compared IQ scores obtained by British teenagers in 1980 and 2008, using the same test. The average had declined by two points on average, but by as much as six points among teenagers in the top half of the IQ scale, a fall that wiped out the previous two decades of gains in that group. This added weight to a 2005 study on a sample of 500,000 young Danish men, tested between 1959 and 2004, showing that performance peaked in the late 1990s but then declined to pre-1991 levels.

These findings conform with a pattern suggesting that the rise in IQ is slowing, and in some cases, going into reverse. In 2002, the psychologist Richard Flynn and political scientist Tatu Vanhanen co-authored IQ and the Wealth of Nations, with a follow-up in 2006, IQ and Global Inequality. The core message was that a nation’s economic success was strongly correlated with its average IQ. Though controversial, IQ turns out to be a consistent indicator of success for individuals, nations and also companies—Microsoft co-founder Bill Gates once described his company as being in the IQ business.

According to the Flynn argument, a six-point decline in IQ would equate with a 0.3 per cent fall in GDP. This could also have social implications. A 2011 study by Intelligence linked average IQ to crime levels—though this correlation could be mediated by the possibility that falling IQ decreases prosperity, which causes an increase in crime.

The search for the Flynn effect’s scientific basis has proved just as controversial as using IQ to measure intelligence. The Flynn effect has been strongest among people of average intelligence or below, and weakest among the very bright, suggesting a trickle-down effect, or redistribution of intelligence. Or perhaps government strategies to reduce the class divide by closing the IQ gap have been successful. In countries such as Britain where the Flynn effect appears to have been reversed, the turnaround came among higher-scoring people first.

No cause for this fall in IQs has been established: the internet, the dumbing down of education, and an obsession with exam results have been suggested. Flynn has argued that youth culture has made a contribution. Although it is not certain that the British and Danish results would be emulated elsewhere, falling IQ is a significant emerging trend. Others contend that the Flynn effect has reached its upper limits and that diet or education can only pull average IQ up so far. Scores cannot rise indefinitely—this would create whole nations of geniuses.

Tenuous evidence suggesting that youth culture or education plays a role emerged from a UCL study published last year. Contrary to earlier belief, it suggests that IQ among individuals can fluctuate during adolescence. This was a small study—33 pupils aged 12 to 16, including high and low achievers. Their IQs were tested in 2004, and again three to four years later. Results found that while the average IQ of the sample remained the same, among individuals it fluctuated by up to 21 points.

Although taken from a small sample, the findings were reinforced by the most novel aspect of the study: brain scans were also taken using magnetic resonance imaging (MRI). This identified a correlation between the variations in IQ scores and changes in aspects of the brain including nerve density. It is not known how these changes relate to IQ, but the existence of an observable correlation between brain structure and intelligence could stimulate research into how cultural and educational factors influence neurological development.

Perhaps this should not be too surprising; it is known that exercise in childhood leads to permanent physiological changes and long-term benefits including increased lifespan. It is likely that, at a molecular level, similar mechanisms are involved, and this is the subject of the expanding field of epigenetics. This covers mechanisms that forge a biological link between nature and nurture, with cultural and educational factors modifying the activity of genes. Epigenetic mechanisms do not alter the underlying genes. This field does not, as is sometimes reported, challenge Darwinian evolutionary theory. Instead it adds a new layer of adaptation. Taking a piano as an analogy, if the keys are the genes, the pianist is the epigeneticist, who decides which ones to bring into play at various times, determining their expression. Occasionally some of the keys are silenced, so that they cannot be played, but in principle can be recovered for future use.

In some cases, neurological changes, caused by exposure to stimulation while young, are heritable. This aspect of the field—the inheritance of epigenetic characteristics—is poorly understood and not universally accepted, but there is research demonstrating its existence. Among the most convincing came in a study, published by Neuroscience in 2009, in which mice were genetically manipulated to impair their memory and then divided into two groups. One group was given stimulation to encourage motor skills. The other was not. Mice in the first group largely overcame their genetically programmed memory deficiency, and passed their improvements to offspring.

While research on human intelligence will always court controversy, there should be no moral or political objection to work examining how neurological development is directed by external factors and what affect these have on health and wealth.

Moreover, when it comes to intelligence, nature may create its own nurture. People inherit a desire to exercise their brains, and this stimulates neurological development. If love of thinking is the key to intelligence—at least of the kind measured by IQ tests—then perhaps there does need to be a change in education, especially in the early years, to develop intellectual curiosity. Then the necessary business of passing exams may take care of itself, and people will no longer leave school feeling, as Oscar Wilde did, that only then can their education begin.

  1. March 28, 2012


    Less reading, more computer games and social (sic) media. What do you expect?

    • August 28, 2012


      If the 1980 IQs were lower than previous ones (and 2008 ones), blaming Hollywood teen comedies, Tatcher, Atari and not enough reading (good luck trying to prove that 80s teenagers were quite readers) would be equally easy. If American IQ had peaked in, say, 1981, you would be able to blame MTV as well.

  2. March 29, 2012


    An interesting article but does it go deep enough? I do not think so. Minor fluctuations in IQ values are to be expected and spurious trends up or down can simply be a feature of compressed time scales.
    Several thought streams are brought forward after reading this article:
    1. Are we more “intelligent” now than we were in say Roman times? No. If our intelligence is evolved then not enough time has elapsed for average intelligence to have changed. By intelligence I mean inherent problem solving ability; the nature/nurture arguement is a circular one in my view since it is nature that determines whether we are aspirational and hence whether we strive (or are nurtured) to “better” ourselves.
    2. In 3000 BC it is estimated that global population was about 50 million. It is now more than 100 times that figure, so maybe living closer together has influenced our perceived intelligence in that the types of problems we need to solve have changed and no longer match the genetic mechanisms already established thus lowering the value of the nature component of IQ and thereby increasing pressure on the nurture component.
    3. As Steven Pinker has pointed out, research shows that it is Peer Group rather than parental influence that is the key nurture mechanism in child development. In my view the greater the population density, the greater the influence of the Peer Group. If the Peer Group squashes intellectual aspiration (as I have sadly witnessed at first hand)then any nurture component in the IQ value will diminish.
    4. Finally I observe, in UK at least, that Jo/Josephine public put a high value on excellence in sport or “entertainment” but do not celebrate intellectual excellence; just consider the arguements over grammar schools and the performance of state schools vis a vis the private sector as indicative. For some reason if one is intelligent then one is a freak, especially if that ability is displayed openly.
    PS. I did once enter (out of curiosity) a MENSA screening test and they subsequently invited me to a full testing session. Unfortunately I was expected to pay a large amount of money for the privilege and travel a considerable distance also; I declined.

  3. March 31, 2012

    J Huddleston

    IQ is just not a believable “measure” of anything beyond being able to solve short puzzles. Readily teachable skill.

    • August 6, 2012


      My view is that [mental] speed and complexity of connection is the core element of IQ, which of course is always comparative. I have a very high IQ and suffered a lot of ‘don’t be so silly’ from adults as a child because they could not keep up with me: studies of gifted children show this is a common experience.

    • August 13, 2012



    • August 27, 2012


      iq cannot be judged only consider by one factor or by test paper . it would be better , if you estimate it on the basic of real life problem solving stategy.

  4. March 31, 2012


    IQ is highly genetically heritable.

    High IQ women have more education and fewer children than low IQ women. UK society therefore operates reproductive selection for low IQ.

    The proportion of the UK population drawn from lower IQ populations particularly in Africa, West Indies and Pakistan has increased through immigration and subsequent differential rates of reproduction.

    Why was it that we cared about falling IQ again? So what are we going to do about it?

  5. March 31, 2012


    J Huddleston

    Have you read “The Bell Curve”? Have you read “The Blank Slate”?

    Yes, some people can be coached some of the time to do better in IQ tests, but life is the ultimate IQ test. Intelligence is a fundamental property of each one of us just as eye colour etc. is. For some false idealogical/psychological reasons western men/women (especially UK men/women) like you are afraid to own up to the obvious. IQ can be successfully measured but it is not PC to go there. Until we do we are all worse off.

  6. March 31, 2012

    Ramesh Raghuvanshi

    I.Q test in my opinion is hoax.If every man is unique how can you judge him statistical research and draw a conclusion.How can you compare boy who raised posh locality of London with boy who is living in jungle of Andaman inland? My grandchildren are more smart than me because they are living more developed world than me naturally their higher than me.Children of developed world have higher I.Q than developing countries.I.Q test result depend on circumstances

    • July 31, 2012


      “I.Q test in my opinion is hoax.If every man is unique how can you judge him statistical research and draw a conclusion…… My grandchildren are more smart than me because they are living more developed world than me naturally their higher than me…… I.Q test result depend on circumstances”

      Would like to mention that being in a developed world does not give you a higher IQ. I believe that intelligence has to be grown. IITian’s(One of the best institutions whose testing pattern,at least till a few years ago, resulted in the selection of intelligent candidates only) kids are not born IITian’s, neither does the environment force them to have high IQ’s. The ”IIT” environment only gives a platform. Whether the kid chooses it depends on the motivation, confidence, peer quality, awareness, desire, experience of elders, communication gap etc…. which is highly individualistic and depends on the nature of the individual to a large extent.

      “IQ is a say a finish line, and people have different starting points for it. If an environment is not provided, the results will be genetic/individualistic , if not, they will depend on the ability of the individual to utilize the environment ”

      environment is an aid for the rest of the people who had a longer distance to travel.whether we use it or not depends.

  7. March 31, 2012

    John Wojewidka

    The very idea of intelligence is complex and unresolved. Our abilities to reason and solve change as our circumstances change.

    Not that long ago, our conscious and subconscious efforts were focused almost entirely on day-to-day survival. Today, those are unequivocally still with us, and for the same fundamental reasons, but the threats aren’t nearly as immediate. Sublimated, they manifest in various other kinds of competition, like buying a bigger car than the guy next door.

    While an argument can be made this is not a healthy change, the fact is we move through the day with concerns that require different skills. Now, one doesn’t need to outsmart a predator or ensuing storm, but might feel an extra hour at the salon will provide that perceived survival edge.

    So, then, our measurements should, in fact, be different, and should reflect more than just what we’ve accepted as benchmark testing.

    I would posit areas of intelligence that haven’t gotten much attention or analysis, such as intuition – or a version, “street smarts” – should be examined much more carefully. While we have been handed the solutions to many mundane problems over the past 100 or so years (how does one get from A to B without injury and within a reasonable time?), with more people and much more information being dumped on us, we are forced to evaluate the incoming far more quickly.

    A standard IQ test is probably still a good indicator of an ability to operate with some effectiveness – spacial, reasoning, etc. – but probably most effective when testing is done very early in life, when environment plays a much smaller role.

    Without going too deeply for this forum, I’m not so sure there is an actual drop in IQ, but quite possibly we are not assessing intelligence as we should.

  8. April 3, 2012

    William Stewart

    That IQ scores are substantially heritable is not open to serious doubt. See, for (a good) example, the work of professor Ian Deary and associates at the University of Edinburgh. Also, IQ, however crude it may be, is the best predictor of job success and of many positive life outcomes. IQ also predicts longevity.

  9. April 27, 2012

    Simon Newman

    Far be it from me to suggest that the decline in top-half IQ might be the reason why the author has confused Richard Lynn, c0-author of IQ and the Wealth of Nations, with James Flynn.

    This is perhaps unsurprising inasmuch as the ‘Flynn effect’ was apparently first noted by Lynn. Otherwise they are quite different; Lynn emphasises dysgenic reasons for the current fall in IQ (which he predicted) – IQ has long been negatively correlated with fertility in developed nations, and IQ is partially heritable, so one would expect to see a decline in IQ over time, especially at the top end. This is so even if there is no significant genetic – nature- component to IQ, since culture – nurture – is also heritable. The weight of evidence seems to indicate that IQ is a mix of nature and nurture.

  10. April 27, 2012


    Surely the British version of Democracy depends on a fairly low IQ amongst the masses.

    Thinking about it American democracy needs it’s fair share of idiots. Who other than an Idiot would vote for the crop of Republicans over the last 20 years.

  11. August 1, 2012

    Vijayaraj R

    its totally true that IQ levels in the person related to the nature and nurture. Because a healthy mind could think much wider than others and we were influenced to think based on the atmosphere we grow .

  12. August 1, 2012


    This article is really helpful for understanding the relationship between economical,political,cultural,technological factors and the I.Q of a person.

  13. August 2, 2012


    IQ is dependent on cicumstances and atmosphere you grow in. It may vary from time to time and most importantaly it’s dependent on concentration. what moe can you expect fron today’s generation who is entangled in TV, computer/mobile games, social networking..thinking ability is fading.

  14. August 5, 2012


    I guess IQ totally dependend on nature and nurture; also surrounding and motivation takes majore role in devekoping the IQ ……..

  15. August 5, 2012

    swati pahwa

    hello to evry1,
    I do not know about the facts and figures about the past and present IQ levels. I can surely, comment that IQ is something which is not dependent on one factor, instead it is being calculated directly or indirectly by inherent factors. I completely agree on the part saying, it also depends on person’s nurture. A person’s IQ has started forming from the zygote, where genes of parents and nutrition are catalyst to it. Further, I would blame ,the easy techniques to solve practical situations of life, is responsible for degrading IQ day by day. e.g Earlier, people used to find number of methods to get news around, not like today where one just switch on the T.V and get world-wide news on a click. Those days every1 used to apply effective intelligence to survive and make their life comfortable. But, I agree time has changed so do we. But there are still many ways to increase our IQ level by reforming our daily routines like exploring our hobbies, thinking of alternatives in life to achieve goals, making proper utilization of appliances( functions) to its limit, balancing every required tasks. etc… and most important , general awareness.
    As my point of view, every one has some unique IQ which could be enhanced further if one has understood his strength and accessibility.

    Thank you.

  16. August 6, 2012


    In my view, the core element of IQ is [mental] speed and complexity of connection. I have a very high IQ, and as a child was often told scornfully by adults ‘don’t be so silly’. because they could not keep up with me. I was on tranquillisers at 16 to slow myself down! Much later, looking at studies of gifted children, I found that my experience was not unusual. [And, to respond to another comment, I haven’t had children – very difficult for very bright womento find suitable men; men tend to want their women to be less intelligent than they are.

    • August 10, 2012

      Mukesh Semalti

      i agree with what u said at the end despite being a guy.

  17. August 10, 2012

    Mukesh Semalti

    hey guys
    i don’t know much about IQ but what i understand is that it is partly inherited and partly develops with the age and what and how we observe things from our surroundings…………..

  18. August 13, 2012

    Aditya Shetty

    I disagree with the earlier claim that IQ level rises for people in developed countries..the article itself contradics this. Fluctuations in IQ levels is a predictable find and i feel it is directly proportinal to what a person has been doing over a period of time.

  19. August 13, 2012


    Hey guys,

    I agree to the view that certainly nature and nurture do shapes the IQ level of an individual…Mind always picks up the things consciously or unconsciously from its surroundings..the more we put our mind idle..the less is its chances of learning new things ..the desire to learn new things goes down if you are not in an environment that motivates you one or the other way….!!

  20. August 13, 2012


    Ah yes, two countries known for their permissive immigration policy exhibit changes in IQ, toward the birth countries of the immigrants they’re taking in, and obviously it’s because of the internet. Got it.

  21. August 16, 2012


    really the evaluation of IQ is a very complex phenomenon ,its a function of many variables , but according to me the best thing is that it can be enhanced or improved continuously by practice ,thinking logically and developing the skills in deductive,critical and analytical reasoning as our brain has got infinite potential to be explored and developed ,and sky is the limit, so an individual becomes as per his/her investments of effort.

  22. August 19, 2012


    Very interesting debate considering that education such as ‘no child left behind’ is kicking in. This could very well cover the fact that IQ’s are dropping. The educational systems global appear to be kicking into covering this. Of note that the stats from the US Department of Labour which states that of resturant workers in the US more than 300,000 of them have a university education. Did university really show them how to clean tables?

  23. August 24, 2012


    spending more time on games,internet and even doing assignment with the help of internet…..and that pasting content from site ,,,,what else u can expect ???

  24. September 6, 2012

    ? Gover

    While mildly interesting, this article is about as significant as observing that: of the three men facing the camera in the photo, all have glasses and two have beards. There is little or nothing said about UK sample sizes or statistical significance except where a para begins ‘This was a small study—33 pupils’

    If you want to know how IQ can vary by large amounts over short periods as a result of missed schooling, this is a good place to start.
    I remember the canal boat kids fell behind further as they got older because they missed even more schooling. This study is 90 years old and people still speak as if IQ is pretty nearly fixed (I grant you, not the author of the article, but some correspondents here).

    I joined Mensa in 1965 (I have a beard now but did not then). A straw in the wind that gives you some idea how valuable IQ is in isolation, is that the Mensa Magazine was for many years called Interim because members could agree on no other title. While there certainly were and are some high achievers in Mensa, the average Mensan could not organise his way out of a paper bag.

  25. February 17, 2013


    If I am not mistaken, the IQ test is designed such that the average is always 100; there is no way for the average of the population to fall. From the article it is clear that the students’ scores were compared against each students’ previous scores. Is this meaningful, statistically and biologically? Regarding statistics, was this just a bland/qualitative comparison of scores, or was it a rigorous comparison? Moreover, in terms of rigorousness, the sample size is miniscule. Miniscule and likely biased, leading to the broader question: How does an individual’s IQ scores change over time? Many hypotheses may be generated to explain why 12 year olds might score higher than a sixteen year old; I will not venture this ground unless it is deemed necessary. But what about an individual’s scores from his/her early 20s versus 30s? 40s? 50s? 70s? Without a broader examination of the trends of “intellectual capacity” or flexibility, I believe it is premature to make any statements about “general trends in society” for a reduction of students’ scores over time.

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