Essay on the Question of Human Intelligence: The Causes of Controversy

Introduction

For centuries, scholars have been fascinated by the nature of human intellect. The emergence of psychology as a discipline distinct from biology, philosophy, and mathematics fuelled further study into human intelligence. However, regardless of the tens of years that have been spent studying human intelligence, it remains a controversial topic. The causes of intelligence are the primary cause of controversy in this field. For years, psychologists have debated over whether intelligence is hereditary or occurs as a result of interaction with one's environment (Plomin & Deary, 2015). This has led to the emergence of the nature versus nurture, with equally strong scholars supporting each side. This paper seeks to contribute to this debate by showing that neither nature nor nurture is entirely responsible for human intelligence.

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Nature versus Nurture

This topic is discussed in part 7.6 of the book. It starts by highlighting the story of Oprah Winfrey, a black-American born into poverty, endured sexual assault while growing up, did drugs, but ended up becoming one of the biggest names in American media (Spielman, et al., 2014). This is such a strong point to start the argument. A superficial look at this story suggests that heredity played the most significant role in her career since her environment was not conducive at all. However, a closer look at the story reveals that it is only after moving in with her father, who imposed strict behavioral expectations on her and brought some stability, that her life settled and her upward trajectory began. Therefore, a change of environment brought about a dearly needed change. The authors then go ahead to cite the Minnesota Study of Twins Reared Apart, which strongly suggested that intelligence is hereditary (Spielman, et al., 2014). The study showed that identical twins raised either together or apart show a higher correlation in Intelligence Quotient (IQ) as compared to fraternal twins who are raised together (Spielman, et al., 2014). However, the authors acknowledge that it is almost impossible to isolate when and how intelligence is passed from parents to children.

To contribute to the other side of the debate, the authors state that the environment in which a child develops shapes their intelligence. To support this, they cite a study that shows the role of the environment in offering stability and triggering the manifestation of various cognitive abilities (Spielman, et al., 2014). The authors also give a glimpse of controversy that follows research into the topic, such as the racial storm that arose after Arthur Jensen published an article suggesting that genetics determined intelligence (Spielman, et al., 2014). In conclusion, the authors suggest that though intelligence may be inherited and one's genetic potential is fixed, environmental stimulation determines whether one reaches their full intellectual potential.

The Equal Role Played by Nature and Nurture

Nature in this debate refers to the pre-wiring brought about by genetic and biological factors. On the other hand, nurture refers to the effect of external factors after birth. Scientific research has shown that both nature and nurture greatly influence the development of intelligence. Studies carried out on identical twins have confirmed without a doubt that heredity has a role in intelligence (Plomin & Deary, 2015). Allelic studies have also shown that parents exhibiting high IQ are likely to give birth to children with high IQ (Wasielewska & Bethke, 2019). Due to this evidence, heredity is often taken as the sole contributor to human intelligence. However, the environment plays an equally important role.

Studies have shown that environmental factors are responsible for the differences in cognitive development seen in children. Some of the environmental factors that have been implicated include the home environment, formal schooling, nutrition, exposure to toxic substances, among others. Socioeconomic status has also been shown to influence intelligence (Makharia, et al., 2016). Though no accurate parameters of measuring the exact contribution that nature and nurture play in the development of intelligence, it is clear that both play equally important roles. None of them contributes to the development of intelligence in entirety, but their interaction produces intelligence.

Genetic factors determine one's susceptibility to environmental influences. Therefore, the expression of the array of abilities determined by heredity is shaped by different environmental factors. Thus, the authors are correct when they claim that a child of average inherited intellectual potential raised in a very stimulating environment will have enhanced intellectual outcomes (Spielman, et al., 2014). The interaction between the two, nature and nurture, vindicates the studies that have suggested that socioeconomic status affects intelligence (Tucker-Drob & Bates, 2016).

Conclusion

The cause of human intelligence is one of the most controversial topics in psychology. The debate on the role of nature and nurture in the development of intelligence has raged on for years. However, the number of supporters at each of the extremes has reduced over the years as more research revealed the roles that genetics and environment play. This paper has shown that both are equally important. The interaction between the two helps in the development and expression of the inherited abilities.

References

Makharia, A., Nagarajan, A., Mishra, A., Peddisetty, S., Chahal, D., & Singh, Y. (2016). Effect of environmental factors on the intelligence quotient of children. Industrial psychiatry journal, 25(2), 189. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5479093/

Plomin, R., & Deary, I. J. (2015). Genetics and intelligence differences: five special findings. Molecular psychiatry, 20(1), 98. Retrieved from https://www.nature.com/articles/mp2014105

Spielman, R. M., Dumper, K., Jenkins, W., Lacombe, A., Lovett, M., & Perlmutter, M. (2014). Psychology. Retrieved from https://openstax.org/details/books/psychology

Tucker-Drob, E. M., & Bates, T. C. (2016). Large cross-national differences in gene and socioeconomic status interaction on intelligence. Psychological science, 27(2), 138-149. Retrieved from https://journals.sagepub.com/doi/abs/10.1177/0956797615612727

Wasielewska, M., & Bethke, K. (2019). Genetic view on intelligence and its heredity. Journal of Education, Health and Sport, 9(8), 481-487. Retrieved from http://www.ojs.ukw.edu.pl/index.php/johs/article/view/7339