In the Lent Term 2024, BrainFeed ran a competition where students in year 10, 11, and 12 completed a 500 word essay on one of 3 given essay titles. Here is our winning entry, written by Louisa A, year 12.
Intelligence can serve as the best predicting factor for important markers in our life. It can predict our mortality, our education, our occupation and our physical and mental health better than any other psychological trait. Although everyone will have their own individual definition and views of intelligence, it can be generally defined as our ability to learn, reason and problem solve. Furthermore, intelligence impacts all our decisions throughout life, even our choice of romantic partner and choices surrounding our own healthcare. Often, intelligence is measured through cognitive tests such as IQ tests. These have shown that intelligence is mostly unchanging throughout our older lives. When IQ tested at age 11 and IQ tested again at age 76, this repeated measures design found a 0.63 correlation between the two age groups. This was the strongest correlation over time of all the other psychological traits measured, showing the importance of understanding where intelligence comes from. Psychological research (including that of determining which factors influence intelligence) can often find itself being divided by the nature vs nurture debate, with every psychologist and even non-psychologist seeming to have formed different conclusions on which is more influential.
Within biological and psychological research into inherited traits (such as intelligence), there are three main laws fundamental to our understanding of this research. Firstly, all psychological traits have genetic influence, demonstrating that at least some of our intelligence must be inherited. Secondly, no psychological trait is entirely heritable, there are always environmental factors affecting this. Lastly, heritability is caused by many genes, all of which have small effects on our intelligence. This produces the diversity we see in individuals, what could be the causing factor between minute IQ score differences besides environmental factors. These laws are an important foundation to our understanding of how much of intelligence is inherited as they demonstrate that both genetic and environmental factors contribute to the diversity in intelligence we see amongst people. Evidently, both nature and nurture work together with intelligent characteristics.
Considering inheritance is controlled by genetics, it seems logical to conduct research into psychological traits such as intelligence with studies involving twins. Although identical twins share the same genetic code (i.e. Inherit the same characteristics) , fraternal twins only share 50%. This is because they are created by two separate eggs being fertilised at the same time, meaning the twins are raised in the womb simultaneously but have the same genetic variation as between siblings (also 50%). Identical twins have been shown to have more similar IQs than fraternal twins, demonstrating that genetics must play a role in intelligence. Furthermore, these twin studies have found that identical twins brought up in different houses had less similar IQs to twins brought up in different houses. This therefore shows that intelligence cannot entirely be inherited, it is a complex combination of genetic and environmental factors. Furthermore, identical twins do not necessarily always have the same IQ, demonstrating this relationship between environmental and genetic factors further.
Additionally, there is a naturally occurring phenomenon known as assortative mating. This occurs when an individual naturally seeks out another individual as a mating partner who has similar genetic traits to their own (similar phenotype or genotype). With psychological traits, this phenomenon was more likely to occur with intelligence. This demonstrates how environmental and genetic factors can co-exist to influence intelligence.
Although genetic factors determine at least a proportion of our intelligence, environmental factors determine our potential to succeed. A highly intelligent child may never be able to express this intelligence due to the environment in which they were raised. Furthermore, children with a lower IQ may appear to have a high intelligence due to more opportunities to improve their intelligence being available, and people who push them to take these opportunities.
Finally, it must be emphasized the discrepancies within the broad idea of intelligence. The psychological trait of intelligence differs from that of emotional intelligence, the ability to determine, perceive, use, understand and manage emotions. This involves self-awareness as well as recognising the need to change patterns of behaviour between different people in order to best handle their emotions. Of course, psychological intelligence is fundamental to our understanding of the world and need to communicate with one another, but the importance of emotional intelligence cannot be understated.
To summarise, intelligence is a highly influential trait. It dictates the way we perceive and interact with the world and is one of our most determining traits for important life markers. Intelligence can be influenced by both genetic and environmental factors in varying proportions between individuals, and our intelligence can be nurtured by our environment to truly flourish. Many genetic and environmental factors (such as the laws of inheritance of psychological traits) must be considered when determining the variable proportion in which intelligence can be inherited.