Is a child's intelligence genetic, or a product of social conditioning?

In My Humble Opinion
1

Not sure if this belongs in GQ, so mods feel free to move if needed. Also, I searched the forums before posting this, but didn’t find any results that fit the bill.

Bit of a back story first:

Was having a discussion the other night over drinks with a few friends about our kids, raising them, etc., and one couple turned the conversation to how their child was just born intelligent (and perhaps I’m not wording this correctly. Maybe a more correct term instead of “intelligent” would be “advanced”).

Now, neither the father nor the mother of this child are what I’d call Mensa-material, but they both seem to have their heads on straight. The wife in particular thinks very highly of her level of intelligence, but I’d call her more…opinionated than intelligent. The majority of their knowledge comes from life experiences, and not higher-education.

Their child (who is 8) is what I’d call, extremely average. The mother likes to mention how she’s testing so high at public school that she’s considering moving her into a private school, but personally I don’t see it. She makes the type of spelling and usage mistakes that you’d expect from a kid her age, has problems with math, etc.

Now, I mention this only to frame the context of the conversation. I didn’t disagree with the claim of their daughter’s intelligence, but I told them that I wasn’t a firm believer that kids are just born smart. I said that by saying that, it takes away from the fact that they’ve developed an environment that nurtures their child’s intelligence, and it gives genetics the credit instead of their parenting.

So is a child’s intelligence genetic, or is it social conditioning? Maybe a bit of both? We hear of child prodigies that have graduated from college at 12, etc. but if their parents never nurtured that intelligence, would we have ever heard of them at all? Are their any stories of uber-intelligent children that were born from parents of average (or sub-average) intelligence?

2

Google “Nature vs. Nurture.”

Entire libraries have been written on this subject with no single answer.

3

Yeah, I realize that, but I’d be interested in hearing Dopers opinions. Mods, perhaps this is better suited in IMHO then?

4

Well so far there seems to be a genetic factor, but it’s clearly not all genetic, at least in the sense that intelligent parents are no guarantee of an intelligent child, and a genius may have unremarkable parents. The effect of nurture as opposed to less predictable genetic factors or the physical environment are much less clear.

5

How can it not be both? Shouldn’t the question be how nature and nurture interact to enhance or diminish intelligence?

6

The academic answer is too long to give here. There are clearly nature and nurture components to intelligence. The main debate is how much and how each contributes. The current thinking is that nature sets the bounds of intelligence and nurture helps it achieve its potential. However, some environmental effects like childhood lead exposure or head trauma can have a permanent impact on cognitive functioning as well.

It is fairly easy to demonstrate informally. Just ask any parent who has more than one child if they think it is mostly nurture. The vast majority will say no because siblings (not including identical twins) are usually both similar and quite different in ways that no one planned even when raised in the same house by the same parents. My brothers and I look alike for example but our personalities and the things we are good at couldn’t be more different and they have been that way since we were very young. OTOH, identical twins separated at birth usually have remarkably similar scores on intelligence tests and often similar interests even when they are raised in very different environments.

7

You can check out any of the many scientific racist threads for doper opinions on nature vs nurture. Anyways back to your OP though, have you ever heard a parent say “Yeah my kid is average smart”? I haven’t.

8

The term heritability is used to quantify the extent to which the variability of a trait within a population is due to genetics or the result of environment. A trait in which the variation is purely genetic has a heritability of 1.0 and a trait with variation explained entirely by the environment has a heritability of 0.

IQ, to the extent is is an accurate measure of intelligence, has a heritability of about 0.75, but with wide variation according to which study you believe. This would indicate that genetics is the more important factor in explaining the variability across the population.

For comparison, weight and body fat has a heritability of about 0.75 to 0.85. Height has a heritability of about 0.9 to 0.95.

9

When I was living in Ohio, decades ago, there were folks pleased when their kid brought home Cs. The comment was “I wouldn’t want him to not be a regular guy.”

10

I think it’s the same as with success in any field – a combination of luck & hard work & talent.

In other words, someone who works hard and has access to the best resources can show intelligence far beyond someone who is born smart and lazy.

11

Heritability is far more complicated than that. It is the result of (in part) genes and gene frequencies in a particular population, at a particular time, and as such, is not a trait-specific quantity. Heritability is itself affected by the environment in which the population finds itself, and so is not fixed; as populations evolve, the heritability of various traits will necessarily change.
Heritability tells us nothing about how a given phenotype is “determined” (e.g., with respect to “nature vs nurture” arguments). A high-heritability trait can still be radically affected by changes in the environment or population. Simply put, heritability is not a predictive indicator of phenotype.

12

Harlan Ellison, I think in The Glass teat, had an essay about the worship of Dumb in America. While Europe seems to respect the poor but very smart - the professor, the expert, etc. - America by contrast dislikes book larnin’, which Ellison typified about the then-current TV ad “whaddaya want, good grammar or good taste?” The cigarette ad made fun of the grammar Nazi who tried to correct “Winston tastes good like a cigarette should…” featuring dancer and singers harrassing said GN for being too smart instead of appreciating a good cigarette.

Certain cultures (Jewish, Chinese) seem to revere education, while good ol’ boy USA seems to think it is not good, not cool, not right to be smart.

Regardless - as others have said, intelligence seems to be somewhere between 50% and 75% hereditary - or at least, built into the child by birth, the gestation development influences. Taking the most charitable view, 50% heredity means there’s a component of 50% that can be enhanecd or lost depending on nurture; meaning a person could probably go from say between 80 IQ to 120 IQ (assuming a reasonably “trainable” intelligence) which takes you from dolt to passable college grad, based on nurture.

One item I read suggested that a major component of learning was exposure to information, especially in the earliest years - and that it’s a wonder that first-world kids are not more stupid than they seem, given that we stick the baby in a crib in a quiet room with just a simple spinning mobile to stare at a blank ceiling for hours on end. COntrast that with a third world child, carried almost everywhere by the mother and gets to see the world, listen to many different adults talk back and forth, see people doing daily taskes, etc.

13

To site a direct and practical example, we can look at the Polgár sisters. Born to László and Klara Polgár, Zsuzsanna, Zsófia, and Judit are unarguably the highest rated family of chess players, all the more notable for being women (chess is heavily dominated by male players). Zsófia is rated as an International Master and Woman Grandmaster, while Zsuzsa and Judit are rated as unrestricted Grandmasters. This wasn’t by any kind of accident. Even before their birth, László espoused the theory that sufficient nurture could elevate native abilities, and set out to demonstrate this via instructing his children in chess. Although László himself is a noted authority on chess–his Chess: 5334 Problems, Combinations and Games will be found on any serious chess enthusiast’s bookshelf and is probably the single most widely published chess book save for Nimzovich’s My System–he is by no means an exceptional player (his daughters could all defeat him at an early age).

Now there is no question that the sisters inherited at least some of the intellectual abilities from their father, but short of any evidence of a recessive “chess gene” that happened to be expressed in all three girls, it is pretty conclusive that an early and systematic education and environment that encourages development of a particular ability, such as the analytical and memory skills required to master chess, can have a profound effect on resulting intellectual ability.

On the other hand, examples of unprovoked and untrained genius also abound. Srinivasa Ramanujan, the Indian mathematician, had no formal training in mathematics when in essentially intellectual isolation from higher mathematics he independently deduced many fundamental and advanced theorems as well as developing new theorems that were original and unconventional. Clearly, no one trained him in mathematics to this degree of ability, and there is no fundamental explanation for or environmental condition to indicate why he was outstandingly brilliant.

Stranger

14

I’ve heard a number of parents imply as much, by comparison with other kids.

15

I read once the genetic factor goes up as you age, when you are a young kid it is only about 0.6, but by the time you are in your late teens it about 0.7-0.8. So 0.7-0.8 for adults which is a strong genetic component.

16

This one is better suited to IMHO. Moved

samclem, moderator

17

Persons are born with certain aptitudes and potentials. A child will only grow so tall, regardless of how well fed; a child will only become so smart, regardless of how much stimulation or education received.
There are many factors which will limit a person before they are able to reach their theoretical limit, so I believe that very few persons grow to fulfill their potential. Given equal treatment and opportunity, kids will do whatever the hell they feel like regardless of what parents expect.

18

I vote biologic, maybe genetic. How many people have grown up feeling like a square peg in a round hole?

19

I vote biologic, maybe genetic. How many thinking people have grown up feeling like a square peg in a round hole?

20

1/3 biological 1/3 environmental and…a variable amount of self direction, which could range anywhere from being entirely influenced by the other two, to completely overwhelming and transcending them.

In some cases, being disadvantaged biologically or environmentally can even be ironically helpful when it leads to someone being more aware of self improvement tools, or to overcompensating.

Environment is a pretty big category though, including factors such as education, money, role models / guides, opportunities, location, and diet.

Biologically there’s a lot of information out there on disabilities, but I don’t see a lot about actual physical advantages.

Also, all three factors can influence each other.