Why is intelligence declining?

The Flynn Effect and the IQ drop

🏷️ Categories: Learning.

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Decade after decade, intelligence tests have shown a steady increase: better cognitive skills, faster thinking, more problem-solving ability. This was called the Flynn Effect (Flynn, 2009).

But here comes the surprise: that trend is no longer continuing.

Worse, intelligence seems to be declining.

Since the late 20th century, scientists have detected a strange drop in IQ scores in several developed countries. Studies such as Bratsberg and Rogeberg (2018) in Norway, Teasdale and Owen (2005) in Denmark have documented this decline.

Something is going on.

Is it the fault of technology, the education system, nutrition, lifestyle?

Let's look at the main theories about this decline in intelligence in the younger generations and how it might affect our future.

Photo by BUDDHI on Unsplash

First the good stuff first: Why did IQ rise over the years?

James R. Flynn found that the average IQ increased by about 1 to 3 points per decade in developed countries such as the US, Norway and France (Flynn, 1987).

The reasons?

1. Education: More access and better teaching methods

With the 20th century came dramatic changes in education.

Compulsory schooling was extended and teaching methods began to focus on abstract thinking. Simple memorisation was abandoned and analysis and problem solving were promoted (Neisser et al., 1996).

2. Nutrition and health: Foundations for a developing brain

Better nutrition played a key role in increasing intelligence.

Eradication of nutritional deficiencies such as iodine and iron deficiency contributed to cognitive development (Benton, 2010). For example, supplementation with these nutrients in deficient children is known to improve their IQ (Zimmermann et al., 2006).

3. Exposure to information and intellectual stimulation

Increased access to information has promoted learning (Greenfield, 2009). In the space of a few decades, large parts of the population have gone from being information isolated to having access to information of all kinds at low cost.

4. More demanding environments and work complexity

With the automation of repetitive tasks, the world of work demanded more analytical skills, fostering the development of intelligence. Modern jobs require analytical, decision-making and problem-solving skills (Author, 2014).

But that upward curve of IQ started to fall...

IQ score from 1938 to 1985 (Sundet, 2014)

2. The decline of IQ

Studies in Europe and elsewhere show that IQ is declining in recent generations. There are multiple hypotheses, but here are the most supported ones:

1. The education system

Yes, we have more access to education, but what are we doing in the classroom?

Teachers have to keep an exhaustive quantification of students, which translates into more exams and evaluations. Faced with this situation, students choose to memorise to pass rather than to understand in depth, as memorising is more efficient for passing (Hirsch, 2019).

The dynamic becomes memorise, pass the test and memorise for the next one, which impoverishes reflection and application of what has been learned (Willingham, 2009).

The result? People with poorer analytical and problem-solving skills.

2. The impact of technology

Never in history has there been so much information. But are we using it well?

• Constant distraction: Multitasking and rapid consumption of digital content reduces the ability to concentrate and learn deeply (Carr, 2010). Multitaskers are known to have more difficulty concentrating and retaining information (Ophir et al., 2009).

• Shallow reading: Reading has been replaced by unstructured content, which damages memorisation and reasoning skills (Wolf, 2019; Greenfield, 2009; Sweller, 1994). Instead of reading a book, it is all short messages with links that take you from one place to another without order.

• Technological dependence: It is increasingly common to have to turn to the internet for any question. It is the Google effect: The tendency to memorise how to search for information rather than remember it (Sparrow et al., 2011). The more mental effort you delegate to technology, the less you stimulate your brain.

Technology is not bad, but its misuse could be harming us.

3. Environmental Factors

• Ultra-processed diet: The cost of high-fat, high-sugar diets is lower than that of quality foods, which has led to increased consumption of refined grains, salt, sugars and saturated fats. At high levels, they impair memory, attention and produce neuroinflammation (Francis & Stevenson, 2013).

• Exposure to pollutants: Lead, mercury, pesticides and microplastics can alter neural development in childhood and reduce people's IQ (Grandjean & Landrigan, 2014). The most notorious case is that of tuna, which, along with other fish such as salmon, accumulate amounts of mercury that can be dangerous if consumed at high levels (Tollefson & Cordle, 1986).

• Less physical exercise: physical activity improves brain function and neurogenesis (creation of new neurons), but modern sedentary lifestyles damage this function (Hillman et al., 2008).

Pollution, lifestyle, unbalanced diets... all could be involved.

The Flynn Effect has been reversed and its causes are unclear, what is clear is that much of it depends on your habits, environment and daily choices.

• Deep reading to reflect and train your attention.

• Conscious use of technology.

• Healthy nutrition.

• Physical activity.

You decide.

✍️ Your turn: Why do you think this change in the Flynn effect is due to? The debate is on.

💭 Quote of the day: ‘I used to find it easy to immerse myself in a book or a long article. My mind would get caught up in the twists and turns of the narrative or the turns of the plot, and I would spend hours wandering through long stretches of prose. That hardly ever happens anymore. Now my concentration starts to wander after a page or two. I get restless, I lose the thread, I start looking for something else to do’. Nicholas Carr, The Shallows.

See you next time! 👋

References 📚

1. Benton, D. (2010). The influence of dietary status on the cognitive performance of children. Molecular Nutrition & Food Research, 54(4), 457-470. URL

2. Flynn, J. R. (1987). Massive IQ gains in 14 nations: What IQ tests really measure. Psychological Bulletin, 101(2), 171-191. URL

3. Flynn, J. R. (2009). Requiem for nutrition as the cause of IQ gains: Raven’s gains in Britain 1938–2008. Economics & Human Biology, 7(1), 18-27. URL

4. Francis, H., & Stevenson, R. (2013). The longer-term impacts of Western diet on human cognition and the brain. Appetite, 63, 119-128. URL

5. Grandjean, P., & Landrigan, P. J. (2014). Neurobehavioural effects of developmental toxicity. The Lancet Neurology, 13(3), 330-338. URL

6. Greenfield, P. M. (2009). Technology and Informal Education: What Is Taught, What Is Learned. Science, 323(5910), 69-71. URL

7. Hillman, C. H., Erickson, K. I., & Kramer, A. F. (2007). Be smart, exercise your heart: exercise effects on brain and cognition. Nature Reviews. Neuroscience, 9(1), 58-65. URL

8. Hirsch, E. D. (2019). Why knowledge matters: Rescuing Our Children from Failed Educational Theories. Harvard Education Press.

9. Ophir, E., Nass, C., & Wagner, A. D. (2009). Cognitive control in media multitaskers. Proceedings Of The National Academy Of Sciences, 106(37), 15583-15587. URL

10. Sundet, J. (2014). The Flynn Effect in Families: Studies of Register Data on Norwegian Military Conscripts and Their Families. Journal Of Intelligence, 2(3), 106-118. URL

11. Teasdale, T. W., & Owen, D. R. (2005). A long-term rise and recent decline in intelligence test performance: The Flynn Effect in reverse. Personality And Individual Differences, 39(4), 837-843. URL

12. Tollefson, L., & Cordle, F. (1986). Methylmercury in fish: a review of residue levels, fish consumption and regulatory action in the United States. Environmental Health Perspectives, 68, 203-208. URL