Contents lists available at ScienceDirect Personality and Individual Differences journal homepage: www.elsevier.com/locate/paid Regional differences in intelligence in the Sultanate of Oman Nasser Said Gomaa Abdelrasheed a,b, ⁎ , Edward Dutton c , Khalid Muslem Aslam Almashikhi d , Jan te Nijenhuis e , Yussef Ahmed Bakhiet Albaraami a a Department of Education, College of Arts and Applied Sciences, Dhofar University, Salalah, Sultanate of Oman b College of Education, Minia University, Egypt c Ulster Institute for Social Research, London, United Kingdom of Great Britain and Northern Ireland d Department of Education, Dean of College of Arts and Applied Sciences, Dhofar University, Salalah, Sultanate of Oman e Experimental and Applied Psychology, Free University, Amsterdam, the Netherlands ARTICLE INFO Keywords: Standard Progressive Matrices Intelligence Dhofar Muscat Oman ABSTRACT We administered the SPM to a sample of 1614 pupils aged between 9 and 18 in 2018 in the Dhofar region of Oman. Our results were compared to a previous administration of the SPM to 5139 pupils aged 9 to 18 in the capital region of Muscat which took place in 2001. We found that the IQ of Muscat in 2001 is substantially higher than the IQ of Dhofar is 17 years later. As there are only a small number of studies on the mean IQ in Oman, we did not apply a Flynn-effect correction. It is found that these regional IQ differences are paralleled by regional differences on many correlates of IQ such as life expectancy and years spent in schooling. We suggest three key factors as likely explaining the difference in IQ: poorer conditions in Dhofar, the association between intelligence and urban migration, and the effects of the Dhofar Rebellion. Other possible explanations are also examined. 1. Introduction A considerable amount of scholarship has found that there are re- gional differences in intelligence within nations and that regions with lower average scores on IQ tests have lower levels of socioeconomic development (Lynn, Fuerst, & Kirkegaard, 2018). This has been estab- lished in regions of the UK (e.g., Carl, 2016b; Lynn, 1979), France (Lynn, 1980), Italy (e.g. Lynn, 2010), Spain (Lynn, 2012), Portugal (Almeida, Lemos, & Lynn, 2011), Germany (Roivainen, 2012), Finland (Dutton & Lynn, 2014), China (Lynn & Cheng, 2013), Japan (Kura, 2013), the USA (e.g. Pesta, McDaniel, & Betsch, 2010), Turkey (Lynn, Sakar, & Cheng, 2015), Brazil (Fuerst & Kirkegaard, 2016), Mexico (Fuerst & Kirkegaard, 2016), Egypt (Dutton et al., 2019), Sudan (Bakhiet & Lynn, 2014), and Russia (Grigoriev, Lapteva, & Lynn, 2016). Carl (2016a, 2016b) has scrutinized data from local governments areas in Britain and has reported that the average IQ of those who live within a ‘local authority’ area correlates with a general socioeconomic factor at r = 0.58. It has been shown that IQ is consistently correlated with SES (e.g., Jensen, 1998) and that a country's average IQ predicts socio- economic differences between nations, although additional factors also manifestly play their part. It has been demonstrated that national IQs strongly correlate with other national-level measures of cognitive ability, such as international assessment tests (Lynn & Vanhanen, 2012) and the much-criticised national IQ scores of Lynn and Vanhanen have been independently and systematically recalculated and very strongly correlate with the disputed originals (Becker, 2018). There remains discussion over the issue of causation. Lynn and Vanhanen (2012), for example, aver that intelligence is approximately 0.8 heritable on adult twin studies, IQ is relatively invariant across a person's life time, ethnic minorities in Western countries reflect the IQ of their home country, and that highly intelligent peoples living in harsh conditions nevertheless still have a high IQ and do well in eco- nomic terms, such as the Chinese in Singapore. As such, Lynn and Vanhanen aver, IQ is causal in regional and national differences in socioeconomic variables. They also maintain that, each generation, simply by chance unusual gene combinations, some higher-IQ people are born into poor families and these people generally migrate out of these conditions (Jensen, 1998), consistent with the idea that IQ is causal. In line with the idea that IQ is causal, Kura, te Nijenhuis, and Dutton (2019) have shown that regional differences in IQ in Japan are on the g factor, which means that the largest differences are on the most genetically-influenced subtests within the IQ battery. Others insist that the causality is predominantly the other way round: suboptimal con- ditions bring about lower mean IQ (e.g., Wicherts, Borsboom, & Dolan, https://doi.org/10.1016/j.paid.2019.05.014 Received 11 March 2019; Received in revised form 22 April 2019; Accepted 13 May 2019 ⁎ Corresponding author at: Department of Education, College of Arts and Applied Sciences, Dhofar University, Salalah, Sultanate of Oman. E-mail addresses: nabdelrasheed@du.edu.om (N.S.G. Abdelrasheed), khalid@du.edu.om (K.M.A. Almashikhi), yalbarami@du.edu.om (Y.A.B. Albaraami). Personality and Individual Differences 148 (2019) 7–10 0191-8869/ © 2019 Elsevier Ltd. All rights reserved. T