A new study by United States scientists that suggests people in developing countries like Nigeria are not as intelligent as those in the developed climes because diseases have chained the former’s initiative, has generated fufore worldwide
The report claims that people in developing countries where diseases are rife have lower intelligence quotients because their bodies divert energy from brainpower to fighting diseases.
In hot nations blighted by deadly infections, the priority is survival and populations have evolved to develop stronger immune systems rather than intelligence, insists the controversial theory.
Already, some critics are warning that the study can stoke the fire of racism if it is suggesting that people in the developing countries are not as intelligent as those in cooler, richer climes, according to The Mail of London.
Others pointed out that the ancient Persians, Greeks and Romans lived in hot climates and still boasted extraordinary civilisations.
However, a development scholar, Prof. Ikechukwu Nwosu, says the study is suspicious, arguing that while disease and poverty can affect performance, their relationship with IQ “is not sustainable.” He says that there are many intervening variables affecting IQ development and diseases are just one of them.
The scientists claim that their report, which was released last week, can explain why national IQ scores vary around the world and are lower in some warmer countries stricken by diseases such as malaria, tetanus and tuberculosis.
The researchers behind the theory claim the impact of disease on IQ scores has been under-appreciated, and believe it ranks alongside education and wealth as a major factor that influences cognitive ability, reports The Guardian of London.
Attempts to measure intelligence around the world are fraught with difficulty and many researchers doubt that IQ tests are a suitable tool for the job. The average intelligence of a nation is likely to be governed by a web of interwoven factors.
The latest theory, put forward by Randy Thornhill and others at the University of New Mexico, The Guardian of London notes, adds disease to a long list of environmental and other issues that may all play a role in determining intelligence. Thornhill made the news in 2000, when he co-authored a provocative book called A Natural History of Rape in which he argues that sexual coercion emerged as an evolutionary adaptation.
Writing in the journal, Proceedings of the Royal Society, Thornhill and his colleagues explain that children under five devote much of their energy to brain development. When the body has to fight infections, it may have to sacrifice brain development, they say.
To test the idea, Thornhill’s group used three published surveys of global IQ scores and compared them with data from the World Health Organisation on how badly infectious diseases affect different countries. The list included common infections, such as malaria, tetanus and tuberculosis.
The scientists found that the level of infectious diseases in a country was closely linked to the average national IQ. The heavier the burden of disease, the lower the nation’s IQ scores. Thornhill believes that nations who have lived with diseases for long periods may have adapted, by developing better immune systems at the expense of brain function.
“The effect of infectious disease on IQ is bigger than any other single factor we looked at,” said Chris Eppig, lead author on the paper. “Disease is a major sap on the body’s energy, and the brain takes a lot of energy to build. If you don’t have enough, you can’t do it properly.”
“The consequence of this, if we’re right, is that the IQ of a nation will be largely unaffected until you can lift the burden of disease,” Eppig added.
“It’s an interesting and provocative finding,” the director of the UCL Institute of Cognitive Neuroscience, Mr. Geraint Rees, tells The Guardian of London.
“It explains about 50 to 60 per cent of the variability in IQ scores and appears to be independent of some other factors such as overall Gross Domestic Product.”
“The authors suggest that more infectious diseases could lead to lower IQ scores through an impact on brain development. This is an interesting speculation, but the data don’t prove it one way or the other,” he said.
“A bigger problem is that it might be driven by a third factor that affects both infectious disease prevalence and IQ test scores.”
For reasons that are unclear, IQ scores are generally rising around the world. Thornhill suggests monitoring rates of infectious diseases in nations as they develop, to see if they decline and IQ tests scores rise.
Critics of the study, however, argue that there are many different kinds of intelligence that Western academic-based IQ tests fail to measure.
Low IQ does not necessarily translate into stupidity or incompetence, they said. People in hot countries have the intellectual skills to survive in very difficult environments.
The research could be abused to rationalise racism, just as the Nazis perverted scientific study in the 1930s, some critics, according to The Guardian of London.
Experts pointed out that children fighting debilitating diseases are likely to miss a lot of school, which could be the real reason for a lower IQ score, not compromised brain development.
Nwosu, who is the immediate past director of the Institute of Development Studies, University of Nigeria, says nobody is born with low IQ but environmental factors can affect IQ development.
“I agree with the study that diseases can affect IQ development but I disagree with it if it is suggesting people in developed countries have higher IQ than people in developing countries,” says Nwosu who is currently the Dean of the Business Faculty of University of Nigeria.
“From that perspective the study is suspicious. Yes, certain conditions may affect one’s capacity to develop one’s IQ to the optimum, but nobody is born with low IQ whether in developed or developing countries. There are people in developing countries with high IQ; there are also people in developed countries with low IQ.”
But a professor of psychology at Ulster University, Richard Lynn, said disease and IQ are a two-way relationship, with low national IQs being partly responsible for widespread infectious diseases.
“In recent decades, HIV has been a serious infectious disease, and it has a high infection rate in low IQ countries, especially in southern Africa, where it is present in around 30 per cent of the population … This is attributable to the low IQ of the population who do not understand the way the infection is contracted, and have erroneous beliefs about how to prevent infection.”
Indeed, the claims of the new study will excite Lynn as they are similar to the claims made in the controversial 2002 book, IQ and the Wealth of Nations, which he co-authored with Dr. Tatu Vanhanen, Professor Emeritus of Political Science at the University of Tampere, Tampere, Finland.
The central argument of IQ and the Wealth of Nations is that the average IQ of a nation correlates with its Gross Domestic Product; that is, low GDP can cause low IQ, just as low IQ can cause low GDP. The authors state that average IQ differences between nations are due to both genetic and economic factors.
The book includes the authors’ calculation of average IQ scores for 81 countries, based on their analysis of published reports. For 104 of the 185 nations, no studies were available. In those cases, the authors used an estimated value by taking averages of the IQs of neighbouring or comparable nations.
The authors assigned Hong Kong the highest IQ estimate of 107 followed by South Korea which they assigned 106 and Japan, which was assigned 105.
Morocco was assigned the highest 1Q average in Africa-85, followed by Egypt-83. The authors assigned Zambia the highest in sub-Saharan Africa-77, followed by Congo Brazzaville and Uganda which were both assigned 73. Nigeria was assigned 67 behind Kenya, South Africa, Sudan, Tanzania and Ghana.