After watching the TV series “Basic Law of Genius”, have you admired mathematical geniuses and inspired your enthusiasm for mathematics? So, is mathematical talent hereditary? Now, here comes the scientific answer.
Men are clearly ahead when it comes to solving math problems, but women are narrowly ahead when it comes to mental arithmetic
When people search for the genetic basis of math talent, one approach is to examine the correlation of math achievement in siblings, especially identical twins.
Identical twins have the same genotype and often show similar levels of mathematics. Fraternal twins share only half of their genes, and there are large differences in math scores, with one sometimes good at math and the other average. By comparing multiple pairs of identical and fraternal twins, “heritability” can be measured. According to research conducted by Steven Vandenberg in the 1960s, heredity accounts for 50 percent of mathematics, suggesting that about half of the variance in mathematics achievement is due to genetic differences between individuals.
However, this explanation remains highly controversial. In fact, twin research methods are influenced by many details. For example, studies have shown that identical twins tend to receive the exact same education by being in the same classroom and taught by the same teachers, compared to fraternal twins. The reason they have similar talents may be that they have the same education rather than that they have the same genes.
Another potential effect is that in the mother’s womb, nearly 70 percent of identical twins share a placenta, or the same set of embryonic membranes. Obviously, this doesn’t happen in fraternal twins because they come from separate eggs. Similar biochemical components of the uterine environment allow identical twins to develop identical brain patterns. Even if the heritability of mathematical talent is proven, twin research methods cannot pinpoint exactly which genes are involved in the research process.
To take an extreme example, imagine a gene that affects body size. If its carrier plays basketball regularly and ignores math education, that gene may have a negative impact on math ability!
Another vague but intriguing thread in the search for the biological underpinnings of mathematical talent is contrasting differences between men and women. High-level mathematics is almost exclusively the domain of men. In Steven Smith’s book on brilliant mental arithmetic, he describes 41 computing wizards, of which only 3 are women. Male advantage in mathematics is a worldwide phenomenon.
However, the significance of this phenomenon for the general population is limited, except that the mathematical elite is almost exclusively male. Across the population as a whole, men were weaker in math.
Men are clearly ahead when it comes to solving math problems, but women are narrowly ahead when it comes to mental arithmetic. Finally, the differences between males and females emerged at the beginning of kindergarten, before any systematic advantage of males in mathematics was not detected. Especially in early infancy, men are no better at math than women.
Biological variables do affect math talent
In our education system, math acts as a filter at several key stages, each of which is easier for boys to pass than for girls. Ultimately, women in our society rarely have access to top-level training in math, physics or engineering.
Many factors in psychology and sociology put women at a disadvantage in mathematics. Surveys show that, on average, women show more anxiety than men in math courses; they are not confident in their abilities; they see math as a typically male activity and rarely in their careers can be used. Plus, their parents, especially their fathers, would feel the same way.
Clearly, these stereotypes have grown into a kind of self-fulfilling prophecy. Many young women lack enthusiasm for mathematics, and their belief that they will not be successful in the field causes them to ignore mathematics courses and thus lead to their lower level of ability in mathematics.
In China, the higher-achieving female teens achieved math scores that not only surpassed American female teenagers, but also American male teenagers. This proves that the impact of gender differences is smaller than the impact of educational strategies. A meta-analysis of multiple literature shows that the average difference in math scores between men and women in the United States has halved over 30 years, an improvement that has been accompanied by a rise in the status of women over the same period.
So do biological sex differences also play a role in other disparities? Although no neurobiological or genetic determinants of male math dominance have yet been found, a growing body of clues has led to suspicions that biological variables do influence math ability, albeit subtle.
Someone selected a group of mathematically gifted children and found that the ratio of boys to girls was 13:1. Compared with the unselected group, these gifted children were twice as likely to have allergies, four times as likely to be short-sighted, and twice as likely to be left-handed, and 60 percent of them were the firstborn. Obviously, it is not entirely unfounded to imagine the archetype of the scholar as a left-handed, sickly, and bespectacled only son.
Math ability significantly affected by gender-related neurological abnormalities
In addition, there are some extreme but conclusive cases in which math ability is clearly affected by gender-related neurological abnormalities. For example, most of the computing geniuses among the “mentally retarded scholars” suffer from autism, a neurological disorder four times more common in boys than in girls. Indeed, autism is associated with variants of the X chromosome, as in Fragile X syndrome.
In contrast, Turner syndrome, a genetic disorder that affects only women, is associated with a deletion of the X chromosome. In fact, in addition to certain physical deformities, women with Turner syndrome also exhibit severe specific cognitive impairments in mathematical and spatial mental representations, even though their IQs may be at normal levels. Part of the reason is the abnormal secretion of sex hormones caused by ovarian atrophy. In fact, early hormone therapy improved their cognitive performance in math and space.
We still don’t have a satisfactory explanation for these mysterious links between sex, X chromosomes, hormones, handedness, allergies, birth order and mathematics. All we can do today is to describe the most probable chain of cause and effect in a way that creates an Impressionist painting, what some scientists call “the story of what it is.”
Neuropsychologist Norman Gerschwind and his colleagues believe that elevated testosterone levels during pregnancy may affect both the immune system and the differentiation of the brain hemispheres. Testosterone may cause slower development of the left hemisphere of the brain. It is speculated that the possibility of left-handedness will increase as a result, and at the same time, the ability to manipulate spatial mental representations that rely on processing in the right hemisphere of the brain will also improve.
This refined sense of space in turn makes it easier to manipulate mathematical concepts. Because testosterone is an androgen, this putative cascade may affect men more than women. At the same time, it is not difficult to understand that it may be controlled by part of the genes of the X chromosome, which explains the heritability of mathematical and spatial predispositions.
Among the many clues surrounding this still puzzling phenomenon is that male hormones can directly affect the organization of the developing brain. During development, subjects with abnormal levels of sex hormones showed altered spatial and mathematical processing. Under the influence of this hormonal change, men’s brains may be organized slightly differently than women’s. Neural circuits may be subtly altered in a as-yet-unknown way, which could explain why males have slightly more agile agency in abstract mathematical spaces.
Given the current state of knowledge, it is impossible to find a simple, deterministic explanation for mathematical genius beyond the vagueness of theory, but it would be naive to expect a direct link between genes and genius. They are so far apart that only multiple twisted causal chains can fill the gaps. The emergence of genius is the result of a combination of factors, including genetics, hormones, familial factors, and education.
Biological factors and environmental effects are intertwined in an unbreakable chain of cause and effect, and it is impossible to predict genius through biology, or combine two Nobel Prize winners to produce a baby Einstein.