Late last year, I published an article (Warne, in press) on a widely used database of estimated average IQs for every country in the world. This is a touchy topic, but I decided to wade into it anyway because people were often taking too simplistic of a view of the scores — either rejecting them outright or accepting them unquestioningly. The article has been well received so far, and I hope that it results in a more thoughtful consideration of these scores.

Among the issues associated with national IQs that I addressed in the article is the meaning of very low estimated mean IQs for some countries. Some people have found these IQs troubling, especially averages below 70, and they have mistakenly believed indicate that the average indicates that the majority of people in a country would have an intellectual disability. I blogged about this interpretation in 2020, and the article develops that train of thought further.

When discussing how to interpret very low mean IQs, I stated:

A conservative interpretation that I believe can safely be applied . . . is that the scores measure how well a country’s citizens have been trained to solve standardized, abstract problems on tests.

Warne (in press, p. 19, emphasis in original)

When I wrote those words in 2022, I believed (for good reason) that a lack of high-quality schooling was a major cause of extremely low IQs, as indicated by the correlation between national mean IQ and mean years of education of r = .51 to .80 (Lynn & Becker, 2019, p. 216). Additionally, research on the Flynn effect indicates that additional schooling strongly contributes to increased IQs throughout the world (Pietschnig & Voracek, 2015), and an excellent meta-analysis on the topic shows that an additional year of schooling raises IQ by 1-5 points (Ritchie & Tucker-Drob, 2018).

This leads to a natural follow-up questions: How does education raise IQ? It turns out that James Flynn had the key. His view was that education — and other aspects of modern life — give people “scientific spectacles” that allow people to think in abstract principles instead of their concrete, everyday reality (Flynn, 2012). Once a person can think about the world abstractly, they can use logic, identify the implications of a hypothetical situation, or apply ideas from one field into another. The fact that they can then correctly answer more questions on intelligence tests is just a happy bonus.

Recently, I have found some classic studies that support Flynn’s (2012) opinion. For this post, I’ll only focus on the research on object classification because it is one of the most basic abstract skills that appear on intelligence tests. Also, I think that the evidence is very strong regarding how humans gain this skill. I expect the principles to apply to other skills that intelligence tests measure, though (e.g., using analogies).

Evidence Supporting James Flynn

Research in Central Asia

To support his view, Flynn (2007) cited the work of Soviet neuropsychologist Alexander Luria (1976), who led two scientific trips to what is now Uzbekistan and Kyrgyzstan in the early 1930s. At the time Central Asia was in the early stages of collectivization. Many people still lived a traditional lifestyle; most were illiterate because formal education had only been recently introduced. Even among those who were living a comparatively modern lifestyle, their experiences were limited to working in farming collectives. Few had any contact with nearby cities, let alone the outside world.

Alexander Luria. Source: Wikimedia Commons

Luria found that when given a series of objects, his uneducated respondents would classify objects by whether they are used together — and not membership in an abstract category. For example, Luria’s team showed pictures of four objects (a hammer, a saw, a hatchet, and a log) to respondents and asked which one does not belong. Many uneducated respondents would not recognize that the first three items are all tools and that the log is not. Here’s a typical exchange between the experimenter and a 39-year-old illiterate respondent:

But one fellow picked three things–the hammer, saw, and hatchet–and said they were alike.

“A saw, a hammer, and a hatchet all have to work together But the log has to be here too!”

Why do you think he picked these three things and not the log?

“Probably he’s got a lot of firewood, but if we’ll be left without firewood, we won’t be able to do anything.”

Luria (1976, p. 56)

A 25-year-old illiterate man who was posed the same problem stated:

“They’re all alike. The saw will saw the log, and the hatchet will chop it into small pieces. If one of these things has to go, I’d throw out the hatchet. It doesn’t do as good a job as a saw.”

Luria (1976, p. 60)

Conversely, people with even a little education could identify the log as the item that did not belong with the other four. This is shown in the response of a “barely literate” 20-year-old:

“The wood doesn’t fit here. Wood just lies on the ground, whereas the other three are used for different kinds of work.”

Luria (1976, p. 75)

Apparently, it does not take much education or experience with modern life to classify objects. It is important to note, though, that some of Luria’s interviewees needed follow-up questions to get to the correct answer. For people with little education, abstract classification may not be natural, but it is possible. In the end, only 4% of illiterate peasants could engage in abstract classification, whereas 70% of “barely literate” collective farm activists could do so, and 100% of young people with 1-2 years of schooling could do so (Luria, 1976, p. 78). The uneducated respondents’ thinking was very resistant to correction. Even when they were explicitly told that the hammer, saw, and hatchet were all “tools,” the illiterate sample members still insisted that the log belonged with the other objects (Luria, 1976, pp. 93-97).

Flynn (2007) interpreted Luria’s results as indicating that abstract thought is not the default way of thinking in humans. Unless taught otherwise, humans normally think in terms of their everyday experience and do not extrapolate beyond that. Thus, when these people take a Western intelligence test that is full of abstract questions, they perform poorly because they are unfamiliar with abstract thinking. These people can function very well in their environment because they have a great deal of experience with the objects, social roles, and challenges of their everyday life.

Research in Liberia

Another classic study supports Flynn’s (2007) interpretation. Cole and his colleagues (1971) performed years of field work on the thought processes of the Kpelle people in Liberia, including research on the Kpelle’s method of classifying objects. The results are similar to what Luria (1976) found. When the Kpelle were given a series of objects, they grouped them together by function.

For example, a potato and a knife were put together because “you take the knife and cut the potato.”

Cole et al. (1971, p. 79)

Again, this shows that the default classification method for humans is to classify objects together by whether they are used together. This was true, even though Cole et al. (1971) in other studies found that the Kpelle did have coherent categories that the objects could fit into (e.g., “food,” “tools,” “utensils”). However, Kpelle individuals with some Western schooling were more likely to classify objects by the abstract categories they belonged to.

Kpelle girl, May 1968. Photo by John Atherton. Source

Interestingly, the Kpelle play a game where leaves are tied to a rope and they must quickly name the leaf and describe its function. When asked to sort leaves into two piles, Kpelle individuals from all walks of life classify leaves into tree leaves or vine leaves with almost complete accuracy (Cole et al., 1971, pp. 88-89). Clearly, classification per se is not the challenge for humans; the challenge is abstract classification when it is disconnected from an untrained person’s experience.

Case study from the Warne home

I have one more piece of evidence regarding how education fosters abstract thought. When my oldest child was in kindergarten, I found him doing a homework activity:

Even with less than a full year of school, my son at age 5 could classifying things using an abstract category. In my opinion, my son’s experience, the data on the Kpelle, and Luria’s research all show that it only takes a little bit of education for humans to start reorganizing their thinking around abstract principles and away from their concrete experience. This experience with abstract thought probably causes an increase in performance on intelligence tests.


Although it does not take much education for humans to start classifying objects abstractly, many people in the world do not have that level of education, or the education is very low quality (Bold et al., 2017). Their thinking probably remains grounded in their everyday experience. When these people take a test that solely measures abstract thinking, they perform poorly. This does not make them stupid, nor does it indicate an intellectual disability. Instead, it shows the disconnect between their natural mode of thought and the unfamiliar test content. Instead of administering abstract tests to people in these countries, a test that contains content that they are familiar with may be better aligned with their problem solving abilities.

I still stand by my view that low national IQs are a measure of how well a population has been trained to solve standardized, abstract problems on tests. That is still an important skill to measure because these countries still have to function in a modern worldwide economy that rewards such abilities — both individually and at the national level. That is not the same as intelligence, and I encourage people to not interpret national IQs below about 75 or 80 as measures of a country’s average intelligence. If I were to rewrite the article today, I would add Luria’s (1976) and Cole et al.’s (1971) findings and use them as evidence that purely abstract tests are inadequate measures of some countries’ national intelligence.

If my interpretation is correct, then countries with the low scores on abstract Western intelligence tests should see IQ gains with even basic education. That is reason for optimism because most of these countries are already working on educating their people better. I hope that psychologists gather data so that the Flynn Effect in developing nations can be better understood.


Bold, T., Filmer, D., Martin, G., Molina, E., Stacy, B., Rockmore, C., Svensson, J., & Wane, W. (2017). Enrollment without learning: Teacher effort, knowledge, and skill in primary schools in Africa. Journal of Economic Perspectives, 31(4), 185-204.

Cole, M., Gay, J., Glick, J. A., & Sharp, D. W. (1971). The cultural context of learning and thinking: An exploration in experimental anthropology. Basic Books.

Flynn, J. R. (2007). What is intelligence? Beyond the Flynn effect. Cambridge University Press.

Flynn, J. R. (2012). Are we getting smarter? Rising IQ in the twenty-first century. Cambridge University Press.

Luria, A. R. (1976). Cognitive development: Its cultural and social foundations. Harvard University Press.

Lynn, R., & Becker, D. (2019). The intelligence of nations. Ulster Institute for Social Research.

Pietschnig, J., & Voracek, M. (2015). One century of global IQ gains: A formal meta-analysis of the Flynn effect (1909-2013). Perspectives on Psychological Science, 10(3), 282-306.

Ritchie, S. J., & Tucker-Drob, E. M. (2018). How much does education improve intelligence? A meta-analysis. Psychological Science, 29(8), 1358-1369.

Warne, R. T. (in press). National mean IQ estimates: Validity, data quality, and recommendations. Evolutionary Psychological Science.