The search for understanding the complex relationship between craniofacial morphology and cognitive characteristics, especially in individuals with high IQ, has been a constant challenge for science. This opinion article seeks to elucidate some of the main scientific findings that point to an intrinsic correlation between these two aspects, with an emphasis on phenotypic plasticity, that is, the ability of an organism to change its physical characteristics in response to genetic and environmental factors.
Based on a literature review, several studies have shown that genes involved in processes such as neurogenesis and myelination, crucial for the development of the nervous system, are also associated with variations in intelligence. Hill et al. (2018) identified that genes expressed in the synapse and those involved in the regulation of the nervous system may be linked to neuronal development and, consequently, to intelligence.
Furthermore, large-scale genomic analyses have revealed genetic loci that contribute to both intelligence and related physical traits. Savage et al. (2018) identified 205 loci linked to intelligence and implicated 1,016 genes through eQTL mapping and chromatin interaction analysis. Many of these genes are expressed in the brain, and variations in their expression may influence the development and maintenance of cognitive traits, highlighting the connection between physical brain traits and cognitive functions.
Another crucial point is the influence of brain structure on intelligence. Toga and Thompson (2005) discuss how brain structure is influenced by genetic factors and how this relates to intelligence, establishing a link between the physical aspects of the brain and cognitive abilities. White matter density and integrity, which are highly heritable, have been shown to correlate with measures of general intelligence, indicating a biological substrate for variations in cognitive performance between individuals.
Studies have also explored the heritability of facial features using three-dimensional imaging and quantitative genetic analyses. Cole et al. (2016) estimated the heritability of specific facial features and explored genetic correlations between these features and other phenotypes, such as intelligence, indicating substantial genetic overlap between facial morphology and cognitive traits.
Finally, research has highlighted facial symmetry as a potential indicator of genetic quality and developmental stability, correlating it with health and intelligence. Jones et al. (2001) suggest that facial symmetry may serve as a visual marker of good genetics, reflecting genetic optimization and a lower incidence of deleterious mutations, aspects theoretically linked to neurological development and higher cognitive abilities.
In summary, the current scientific literature converges on the idea that there is a complex network of interactions between genes, physical and cognitive characteristics. The phenotypic plasticity observed in individuals with high IQ may be a reflection of this intricate relationship, suggesting that the capacity for adaptation and change in response to cognitive and environmental challenges may be intrinsically linked to gene expression. However, more research is needed to elucidate the mechanisms underlying this relationship and its implications for the understanding of human intelligence and its development throughout the lifespan.
References :
Cole, J.B., Manyama, M., Larson, J.R., Liberton, D., Ferrara, T., Riccardi, S.L., … & Spritz, R. (2016). Human facial shape and size heritability and genetic correlations. Genetics, 205(3), 967-978.
Hill, W.D., Marioni, RE, Maghzian, O., … & Deary, I.J. (2018). A combined analysis of genetically correlated traits identifies 187 loci and a role for neurogenesis and myelination in intelligence. Molecular psychiatry, 24(2), 169-181.
Jones, BC, Little, AC, Penton-Voak, IS, Tiddeman, BP, Burt, DM, & Perrett, DI (2001). Facial symmetry and judgments of apparent health: Support for a “good genes” explanation of the attractiveness–symmetry relationship. Evolution and human behavior, 22(6), 417-429.
Savage, J.E., Jansen, P.R., Stringer, S., … & Posthuma, D. (2018). Genome-wide association meta-analysis in 269,867 individuals identifies new genetic and functional links to intelligence. Nature genetics, 50(7), 912-919.
Dr. Fabiano de Abreu Agrela Rodrigues MRSB holds a post-PhD in Neuroscience and is an elected member of Sigma Xi – The Scientific Research Honor Society (more than 200 members of Sigma Xi have received the Nobel Prize), as well as being a member of the Society for Neuroscience in the United States, the Royal Society of Biology and The Royal Society of Medicine in the United Kingdom, the European Society of Human Genetics in Vienna, Austria, and the APA – American Philosophical Association in the United States. He holds a Master’s degree in Psychology and a Bachelor’s degree in History and Biology. He is also a Technologist in Anthropology and Philosophy, with several national and international degrees in Neuroscience and Neuropsychology. Dr. Fabiano is a member of prestigious high IQ societies, including Mensa International, Intertel, ISPE High IQ Society, Triple Nine Society, ISI-Society, and HELLIQ Society High IQ. He is the author of more than 300 scientific studies and 30 books. He is currently a visiting professor at PUCRS in Brazil, UNIFRANZ in Bolivia and Santander in Mexico. He also serves as Director of CPAH – Centro de Pesquisa e Análises Heráclito and is the creator of the GIP project, which estimates IQ through the analysis of genetic intelligence. Dr. Fabiano is also a registered journalist, having his name included in the book of records for achieving four records, one of which is for being the greatest creator of characters in the history of the press.