Influences on Intelligence

There is no one specific gene that will dictate a person's level of intelligence. Instead, it is a combination of different genes influencing different components of intelligence. The CHRM2 gene has been identified to stimulate brain connections involved in various cognitive activities and associations of the SNAP-25 gene in nerve cell communication. Specific sequences in the dysbindin-1 (DTNBP1) gene can produce minor differences in IQ.

In a meta-analysis including data from over 78,000 individuals, researchers found 40 genes, of which the FOXO3 gene and CSE1L gene had the strongest association with intelligence, with a role in apoptosis, or cell death (Sniekers et. al, 2017; as cited in Carson, 2017). This suggests that intelligence may also depend upon the preservation and normal functioning of the nervous system.

The evidence of environmental factors shows that children are not born with fixed levels of intelligence.

On the other hand, other psychologists feel that a child's formative environment shapes intelligence, such that exposure to different settings can affect the development of cognitive skills.

The thickness of the outer layer in some brain regions (e.g., frontal and temporal lobes), and the volume and number of nerve cells have been linked to intelligence. The temporal lobes mainly focus on memory, verbal, and non-verbal learning, while frontal lobes are responsible for the mental skills needed in daily living, such as planning, organizing, and even behavioral and emotional responses in achieving one's goals.

Twin studies demonstrate a genetic aspect in people's IQs. Identical twins show similarities in brain structure and function and intelligence in other areas such as music, sports, and language. Even their IQ test results are comparable to those who took the same test twice.

Among adopted children, similarities in intelligence with their adoptive families are apparent in childhood. As they grow older, these similarities wane as experiences accumulate, and they become more like their biological parents, exhibiting genetic influences on intelligence. The impact of genes on intelligence becomes stronger in adulthood.

Fg. 2 Culture can influence intelligence, pexels.com

Language, customs, and early-life experiences affect the intelligence scores of children whose culture doesn't emphasize Western schooling, or those who aren't well-adapted to the types of questions seen in conventional intelligence tests. Certain cultures prepare children to adapt to the environment in which they live, where they are expected to farm or have certain occupations that don't need formal schooling.

Families' conversational styles can also affect how well a child does in intelligence tests.

Parents' Educational Background and Culture

The educational level of parents is associated with their children's IQ. Parents who've had more education are more likely to be motivated in their children's development. They can inspire their children to learn through their example and create a positive and intellectually stimulating home environment to help increase their children's IQ.

Parenting practices shaped by culture also affect IQ and test scores, such as in one experiment conducted by Segal and Hur (2008; as cited in "IQ: Greatly Influenced by Early Family Life," 2015).

Home Environment

Chaotic family environments (e.g., loud noises) and adverse events experienced in early life negatively affect children's intelligence. They have lower scores on IQ tests and struggle in cognitive development. Insufficient intellectual and emotional support also affects intelligence. Ensuring a positive home environment may help increase children's intelligence.

Socio-economic Status

Children with parents who have higher incomes tend to have higher IQs than those from low-income families. Poverty also lowers IQ; averages in IQ of children from lower socioeconomic groups are lower than middle-class children by about 10-15 points (Bearce, 2009). Problems with access to healthcare also add to the burden.

Parent-child Relationships

Intelligence increases when a child feels cared for, encouraged and loved in his early years. Family nurture displays a more significant impact on intelligence in children's early years; those with higher IQs experience more positive environmental influences. Here we can see the importance of parent-child relationships as parents are the child's first teachers; it is essential to create experiences that will positively impact their intelligence.