By Dr. Vinícius Carlesso
Introduction
The relationship between biology and intelligence has been one of the most intriguing fields of modern science, with implications that extend beyond academia to areas such as education, psychology, and ethics. Among the many biological factors that influence cognitive development, sex hormones such as testosterone have received particular attention due to their role in brain development from intrauterine life through adulthood.
Testosterone, a hormone predominantly associated with men, is also present in women, playing important roles in physical, emotional and cognitive development. Studies suggest that during the prenatal period, testosterone levels can influence the development of specific brain areas, such as the prefrontal cortex and hippocampus, which are directly linked to cognitive abilities such as memory, logical reasoning and spatial skills.
In addition to hormone levels, another crucial factor that contributes to understanding this relationship is genetic sensitivity to the hormone. Polymorphisms in genes related to the androgen receptor (AR) and other components of testosterone metabolism can modulate the way the brain responds to this hormone, directly influencing cognitive performance and the expression of abilities considered exceptional, such as those observed in gifted individuals.
This article seeks to explore how these hormonal and genetic factors relate to giftedness, based on scientific evidence obtained from three main studies. These studies assess everything from testosterone levels in prepubertal children to genetic analysis of polymorphisms associated with androgen sensitivity. The proposal is to offer an integrated view that clarifies how biology can play a fundamental role in the construction of cognitive potential, while raising ethical questions about the use of these findings in the social context.
By investigating these questions, we hope to contribute to a more comprehensive understanding of giftedness that goes beyond exclusively environmental and psychological models, and reinforce the importance of interdisciplinary approaches to deciphering the complexity of human intelligence.
Development
Study 1: “Salivary Testosterone and Intelligence in Prepubescent Children”
This study aimed to investigate the relationship between salivary testosterone levels and cognitive development in prepubescent children. The researchers analyzed 284 children aged 6 to 9 years, divided into four groups: gifted (78 boys and 29 girls), children with average intelligence (43 boys and 57 girls) and children with cognitive challenges (50 boys and 27 girls).
Methodology
Bioactive testosterone was measured from saliva samples collected between 9 and 11 am. Cognitive performance was assessed using the Wechsler Intelligence Scale for Children (WISC) intelligence test, administered by trained psychologists. To avoid external interference, children with specific medical conditions were excluded, and data were adjusted for environmental and demographic variables.
Results
Boys with average intelligence had the highest levels of salivary testosterone. Conversely, gifted children and those with extreme cognitive challenges had lower testosterone levels. This pattern suggests that cognitive extremes share a common biological trait, where testosterone-related factors may play an indirect role.
Study 2: “Visuospatial Abilities and Androgen Receptor Polymorphism”
This study examined how testosterone and genetic variations in the androgen receptor influence visuospatial abilities, such as mental rotation, a skill often associated with intelligence. The research focused on the relationship between testosterone levels, the 2D:4D ratio (an indicator of prenatal testosterone exposure), and the number of CAG repeats in the androgen receptor (AR) gene.
Methodology
Participants underwent mental rotation tests, including cube comparison tasks. Saliva samples were collected to measure testosterone levels, and the 2D:4D ratio was calculated as a marker of prenatal hormone exposure. Genetic analysis focused on the CAG repeats of the AR gene, which modulate androgen sensitivity. Results were adjusted for age and environmental variables.
Results
The data showed that mental rotation ability was more strongly correlated with the number of CAG repeats in the AR gene than with salivary testosterone levels. This finding indicates that genetic sensitivity to the androgen receptor is a more relevant factor than absolute testosterone levels in visuospatial performance, especially in gifted boys.
Study 3: “Genetic Polymorphisms and Testosterone Metabolism in Gifted Boys”
The third study explored the influence of genetic polymorphisms related to testosterone metabolism in gifted boys, comparing them with boys of average intelligence. The main focus was the analysis of genes such as androgen receptor (AR), estrogen receptor beta (ESR2) and sex hormone-binding globulin (SHBG).
Methodology
The sample consisted of 95 gifted boys and 67 boys with average intelligence. CAG repeats in the AR gene were analyzed, as well as other polymorphisms in the ESR2 and SHBG genes. Genotypic comparison was performed to identify differences in androgen sensitivity and hormone availability between the groups.
Results
Gifted boys had a lower number of CAG repeats in the AR gene, suggesting greater androgen sensitivity. Significant differences were also found in the ESR2 and SHBG genes, indicating that genetic modulation of testosterone plays an essential role in the expression of advanced cognitive abilities. These results reinforce the idea that giftedness is influenced by a complex interaction between genetics and hormones.
Integrated Discussion
The results of the three studies presented demonstrate an intricate relationship between hormonal and genetic factors in cognitive development and giftedness, pointing to a more complex interaction than simply absolute testosterone levels. This relationship mainly involves the way the brain responds to testosterone, influenced by genetic variations that modulate the sensitivity and availability of the hormone. The main emerging points and their implications are analyzed below.
1. Role of Testosterone in Cognition: Modulation versus Quantity
Although conventional wisdom might associate intelligence with high testosterone levels, the studies reviewed indicate that the role of this hormone is more indirect. Rather than acting as a universal “booster,” testosterone appears to selectively modulate brain development, depending on factors such as age, sex, and genetic sensitivity.
For example, gifted boys demonstrated greater efficiency in using testosterone, even with lower salivary levels, due to greater androgen receptor sensitivity. This suggests that the efficiency of hormone utilization is more important than its absolute quantity.
2. Genetics and Hormone Sensitivity: The Role of Polymorphisms
Studies on genetic polymorphisms reinforce the idea that giftedness is strongly influenced by the interaction between genes and hormones. The reduced number of CAG repeats in the androgen receptor (AR) gene observed in gifted boys indicates greater sensitivity to androgens, which may optimize the effects of testosterone on the brain. Furthermore, the genes ESR2 and SHBG, which are associated with hormonal regulation, also play a role in modulating intelligence.
These findings open up new perspectives on how genetics can determine how the brain processes hormonal stimuli, creating an environment conducive to the development of advanced cognitive abilities.
3. Sex Differences in Hormonal Impact
Another relevant aspect is the difference observed between boys and girls in the impact of hormones on cognitive development. While gifted boys showed a clearer correlation between androgen sensitivity and specific cognitive abilities, such as spatial ones, gifted girls did not show the same pattern.
This may be related to differences in basal testosterone levels between the sexes or to the influence of other sex hormones, such as estrogen, on female cognitive development. These differences highlight the need for more in-depth studies that investigate how hormones interact with genetic factors in a sex-specific manner.
4. Giftedness as a Multifactorial Phenomenon
The findings suggest that giftedness cannot be attributed to a single hormonal or genetic cause. Instead, it results from a multifactorial interaction involving:
Genetics: Polymorphisms in genes associated with hormonal sensitivity.
Prenatal Environment: Exposure to hormonal levels that shape brain development. Postnatal
Environmental Factors: Social, educational, and cultural stimuli that enhance latent cognitive abilities.
This multifactorial view helps to clarify why not all individuals with similar genetic or hormonal characteristics exhibit giftedness. Interaction with the environment is crucial to the manifestation of this potential.
Conclusion
The relationship between testosterone and giftedness is marked by a complex interaction between genetics and hormones. Studies suggest that giftedness can be partially explained by genetic variations that modulate hormonal response, highlighting the importance of the androgen receptor. Furthermore, differences between the sexes raise questions about the hormonal impact on cognitive development. These findings open avenues for future research, also considering ethical questions about the application of biological information to understand intelligence.
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