Abstract
Recently published maps have suggested a notable spatial association between soil fertility and the mean national intelligence quotient (MNIQ) across the globe. This raises intriguing questions about whether the nutritional impact of soil could influence human intellectual capacity on a worldwide scale. This study seeks to investigate these potential connections by examining the spatial relationships between soil fertility and MNIQ in 126 countries. A soil fertility index (SFI) was developed by integrating soil type and pH data, and its relationship with MNIQ was analyzed using regression and correlation techniques. Geostatistical methods were employed to explore the spatial relationships between MNIQ and SFI. The findings indicated a significant correlation (r = 0.58, P < 0.001) between SFI and MNIQ, accounting for 34% of the variability in MNIQ. Semivariograms for MNIQ, SFI, and their cross-semivariogram were modeled to assess their spatial interrelation. The isotropic semivariograms and cross-semivariogram showed considerable similarity in terms of nugget effect and geostatistical range, suggesting that similar spatial processes may govern the variability of soil fertility and human IQ globally. While these results offer valuable insights into the relationship between soil and human intelligence, it is crucial to recognize that this interplay is complex and influenced by various interconnected factors, including soil management practices, socioeconomic conditions, and cultural traditions. Therefore, collaborative efforts across multiple scientific disciplines and institutions are necessary to comprehensively understand the intricacies of this relationship.