HUMAN intelligence is higher, on average, in some places than in others. And researchers at the University of New Mexico have come up with an explanation, published in the Proceedings of the Royal Society. Comparing the average IQ in a particular country with its disease burden (based on the reduction in life expectancy caused by 28 infectious diseases) reveals a striking correlation. At the bottom of the IQ list is Equatorial Guinea, followed by St Lucia, with Cameroon, Mozambique and Gabon tied for third last. These countries also have among the highest burdens of infectious diseases. At the opposite end of the scale, Singapore, South Korea, China and Japan show the highest intelligence scores and relatively low levels of disease. America, Britain and a number of European countries also place in the top left-hand corner of the chart. For more on this, see article.
The data for the countries included in the study can be found here