Over the past 15 years, books and academic papers have suggested that there are very large differences between the average measured IQs of different countries and ethnic groups. Most relevant for asylum seekers and economic migrants to the EU and UK, the estimated mean national measured IQs for Afghanistan, Syria, and Ethiopia were 75.0, 81.6, and 68.5, respectively.
World map of countries by IQ. Source: Wikipedia
This paper will consider an additional issue that occurs when using western standardized IQ tests on ethnic groups from developing countries. Clearly the topic of national IQs is very controversial because of the implication that people of different races have different IQs. According to the current definitions, it is also necessary to demonstrate that the individual has a significantly low level of adaptive behavior. A significant reduced level of intellectual ability is defined as having measured IQ below about 70, or 75, if one allows a five-point margin of error in the measurement of low IQ. However, historically the emphasis has been on low intellectual ability.
The Controversy of National IQ Scores
It would be nice to be able to dismiss Lynn and Vanhanen’s work as politically motivated and their studies as unsound.
- In spite of being a very controversial area of psychology, the core finding that there are large differences in mean national measured IQs has not been successfully refuted.
- Other independent studies have also produced a wide range of estimated mean national measured IQs, though not as low as Lynn and Vanhanen (2002, 2006, 2012a)’s estimates for sub-Saharan African countries.
- The estimates of national IQs correlate significantly and often highly, with other national demographic, economic, and health variables.
If the estimates of national IQs were subject to significant chance error, then this would reduce the correlation with other variables. Nonetheless, given the weight of evidence it seems likely that there are large differences between the mean measured IQs of different countries. This is not to say that Lynn and Vanhanen (2002, 2006, 2012a)’s studies are not without problems, which undoubtedly they have.
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It has been pointed out by a number of authors that there are obvious methodological problems with using tests that were standardized in the developed world on individuals in developing countries. 2010) and for making estimates of the national IQs of countries for which there was no IQ data, on the basis of IQ data of neighboring countries, which must be subject to error.
Factors Influencing National IQ Scores
The short answer to the question as to why these differences in measured national IQ occur is that we do not know. There have been a number of tentative explanations, which can be grouped into the following broad categories: genetic, environmental, and test error/bias.
Genetic Factors
The idea that the ethnic differences in IQ scores are largely genetically determined has been put forward by a number of authors over the years. It has further been suggested that, over evolutionary time, the people of northern Europe and northern Asia have had to cope with environments that have favored higher intellectual ability, such as cold temperature and/or an environment that is different from the one in which humans first evolved, causing higher intelligence to evolve.
There is some supporting evidence of these hypotheses, Lynn and Vanhanen (2012b) reviewed the relationship between national measured IQ and temperature and suggest there is a clear negative relationship between current winter temperatures, temperatures during the ice age and current national IQs. Similarly, Kanazawa (2008) showed there was a relationship between mean national IQ and distance from central Africa where humans first evolved. However, this is a long way from proof of an evolutionary and genetic cause of the differences in measured IQ as there are other environmental explanations that equally fit these findings.
Environmental Factors
An individual’s true intellectual ability is a function of both his/her genetic potentials and environmental nurture. This is the phenomenon whereby the intellectual ability of the population as a whole, at least in industrialized countries, seems to have gone up over about the last 100 years.
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The evidence for the Flynn effect is therefore strong and demonstrates that the population as a whole has either become more intelligent, and/or has got better at doing IQ tests. It also seems likely that, if as the evidence suggests, the Flynn effect has occurred for the past 100 years at about three points per decade in developed countries, then the average IQ 100 years ago, on today’s standards, would be 70, the point at which we now regard individuals as meeting the intellectual criteria for having an ID. It is also similar to the mean measured IQs found in many developing countries today. This therefore raises the intriguing question as to whether the same factors that caused the measured IQ to be low in developed countries a 100 years ago are also causing developing countries to have low measured IQs today.
Space does not permit a full review of the possible causes of the Flynn effect, so only the most obvious ones will be considered.
Nutrition
The quality of diet varies both across time and across place, so it may well be a cause of both the differences in national IQ and the Flynn effect. A number of authors have suggested that an improved diet with a range of foods containing necessary vitamins and minerals will increase IQ or the lack of this will decrease it.
Disease
As with diet, disease could have both a permanent effect on cognitive development and/or a temporary reduced cognitive performance when an individual is being assessed. Differential prevalence of disease may also be one of the reasons for the difference in national IQs. Disease is more prevalent in developing countries and health care is less available.
Education
In developed countries, there has been a substantial increase in both the amount of time children spend in education and in their overall educational achievements. There is also a wealth of evidence demonstrating that educational achievement is highly correlated with measured IQ within countries. There is, therefore, a clear possibility that one reason why some countries have relatively low mean national measured IQs is because of a lack of education.
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The IQs of people from these countries could therefore be improved by either improving education in those countries or by individuals moving to developed countries where they would be exposed to a western educational system. However, there is no definitive proof that this is the direction of causality.
IQ Scores Different Countries | Explanation | Effecting Factors
Global IQ Rankings: A Comparative Look
As of 2019, the countries with the highest average IQ scores demonstrate strong educational systems, advanced technological development, and a cultural emphasis on academic achievement. These nations often invest heavily in education, research, and innovation, creating environments that foster intellectual growth.
According to a 2019 study by researchers Richard Lynn and David Becker at the Ulster Institute, the highest average IQ scores in the world belong to the Japanese, with the citizens of Taiwan and Singapore close behind.
Here's a look at the top 10 countries by average IQ:
| Rank | Country | Average IQ |
|---|---|---|
| 1 | Japan | 106.48 |
| 2 | Taiwan | 106.47 |
| 3 | Singapore | 105.89 |
| 4 | Hong Kong | 105.37 |
| 5 | China | 104.10 |
| 6 | South Korea | 102.35 |
| 7 | Belarus | 101.60 |
| 8 | Finland | 101.20 |
| 9 | Liechtenstein | 101.07 |
