Abstract
We compare the results of the Standard Progressive Matrices on two samples from Khartoum, one from 1999 (N 6877) and the other from 2010 (N 5659), both aged between 9 and 25. We show that in 7 out of 12 age groups there has been a significant Negative Flynn Effect over this period. Among those aged 9 to 18 - directly comparable as they are population samples - we found a significant aggregate loss of 2.13 IQ points between 1999 and 2010 comparing these two groups. The sample, in part, is elite and we note that a cessation of the Flynn Effect has also been reported in an elite Brazilian sample; another developing country. We examine a number of factors which may be behind our finding, in particular changes in the Sudanese education system, changes in the Khartoum population, and dysgenic fertility in Sudan.
•Negative Flynn Effect in Khartoum•Partly consistent with IQ plateau on elite sample in Brazil.•Dysgenic fertility reported in Sudan.•May reflect issues with country's ‘Muslim Curriculum.’