The late snail expert Stephen Jay Gould famously ranted against IQ research: “The chimerical nature of g [for General factor] is the rotten core of Jensen’s edifice, and of the entire hereditarian school.”
From Psychological Bulletin:
Warne, Russell T.; Burningham, Cassidy
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. … 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. … 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. (PsycINFO Database Record (c) 2019 APA, all rights reserved)
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.