Spearman's g Found in 31 Non-Western Nations: Strong Evidence That g Is a Universal Phenomenon

Spearman's g is the name for the shared variance across a set of intercorrelating cognitive tasks. For some-but not all-theorists, g is defined as general intelligence. While g is robustly observed in Western populations, it is questionable whether g is manifested in cognitive data from other cultural groups. To test whether g is a cross-cultural phenomenon, we searched for correlation matrices or data files containing cognitive variables collected from individuals in non-Western, nonindustrialized nations. We subjected these data to exploratory factor analysis (EFA) using promax rotation and 2 modern methods of selecting the number of factors. Samples that produced more than 1 factor were then subjected to a second-order EFA using the same procedures and a Schmid-Leiman solution. Across 97 samples from 31 countries totaling 52,340 individuals, we found that a single factor emerged unambiguously from 71 samples (73.2%) and that 23 of the remaining 26 samples (88.5%) produced a single second-order factor. The first factor in the initial EFA explained an average of 45.9% of observed variable variance (SD = 12.9%), which is similar to what is seen in Western samples. One sample that produced multiple second-order factors only did so with 1 method of selecting the number of factors in the initial EFA; the alternate method of selecting the number of factors produced a single higher-order factor. Factor extraction in a higher-order EFA was not possible in 2 samples. These results show that g appears in many cultures and is likely a universal phenomenon in humans. Public Significance Statement This study shows that one conceptualization of intelligence-called Spearman's g-is present in over 90 samples from 31 non-Western, nonindustrialized nations. This means that intelligence is likely a universal trait in humans. Therefore, it is theoretically possible to conduct cross-cultural research on intelligence, though culturally appropriate tests are necessary for any such research.