Nature v Nurture

Junior D

Is intelligence inherited? or is there no definite answer?

IrishKnight

This is a great question! From my understanding there is no definite answer. There is no single "smart gene" in humans. However, it might be that intelligence can be affected by a number of genes rather than just one. People often think that there is a single gene for everything, however, more often than not it a number of genes which contribute to a trait. A prime example of this would be eye colour.

But I digress. While I am not high up on the genetics of intelligence, I can safely say that they do indeed play an important part. Look at Downs Syndrome (DS). DS is a genetic disorder which results from an error in chromosome 21. People with DS have three rather than the normal two copies of the chromosome. Now, when we look at such people we often find learning problems suggesting that some of the genes in chromosome 21 are important for intelligence/learning.

But, it also comes down to nurture. Lets say that there was a single gene which controlled intelligence, someone with this gene would still need to go to school and be taught. A good real life example of this would be height. Someone could have all the genes in the world to make them tall but if they do not gain adequate nutrition, they will not grow to their full potential.

Hope that is of some help, any more questions feel free to ask away.

fontanalis

IrishKnight wrote: »

This is a great question! From my understanding there is no definite answer. There is no single "smart gene" in humans. However, it might be that intelligence can be affected by a number of genes rather than just one. People often think that there is a single gene for everything, however, more often than not it a number of genes which contribute to a trait. A prime example of this would be eye colour.

But I digress. While I am not high up on the genetics of intelligence, I can safely say that they do indeed play an important part. Look at Downs Syndrome (DS). DS is a genetic disorder which results from an error in chromosome 21. People with DS have three rather than the normal two copies of the chromosome. Now, when we look at such people we often find learning problems suggesting that some of the genes in chromosome 21 are important for intelligence/learning.

But, it also comes down to nurture. Lets say that there was a single gene which controlled intelligence, someone with this gene would still need to go to school and be taught. A good real life example of this would be height. Someone could have all the genes in the world to make them tall but if they do not gain adequate nutrition, they will not grow to their full potential.

Hope that is of some help, any more questions feel free to ask away.

That sounds reasonable, so would it be fair to say some people are more genetically pre-disposed (think that's the term) to be be intelligent.

IrishKnight

fontanalis wrote: »

That sounds reasonable, so would it be fair to say some people are more genetically pre-disposed (think that's the term) to be be intelligent.

If there is a genetic link, (which in limited knowledge of genetics there appears t be, just we haven't found it yet), then yes...ish.

Things in genetics are rarely clean cut, there is nothing to be said that someone who doesn't have the "smart genes" to become just as smart as someone who has them. It might be harder, or they might have to work more etc. Having said that I am by no means an expert on this...

Piste

fontanalis wrote: »

That sounds reasonable, so would it be fair to say some people are more genetically pre-disposed (think that's the term) to be be intelligent.

Yes that would be fair to say. The current school of thought is that nature provides a scale of intelligence we can be placed on, whereas nurture decides where on the scale we lie, so for example, someone's genetics could determine they could have an IQ of between 90 and 120, a good upbringing/environment could place them at the higher end of the scale, whereas a poor upbringing/environment could place them at the lower end.

fontanalis

Piste wrote: »

Yes that would be fair to say. The current school of thought is that nature provides a scale of intelligence we can be placed on, whereas nurture decides where on the scale we lie, so for example, someone's genetics could determine they could have an IQ of between 90 and 120, a good upbringing/environment could place them at the higher end of the scale, whereas a poor upbringing/environment could place them at the lower end.

So opportunity may be the biggest factor?

Piste

Not necessarily, I'm not sure what the weighting is. Nature seems to set the possible intelligence you can have, but nurture seems to be responsibile for how much of that potential you fulfill.

fontanalis

Piste wrote: »

Not necessarily, I'm not sure what the weighting is. Nature seems to set the possible intelligence you can have, but nurture seems to be responsibile for how much of that potential you fulfill.

Opportunity may be the wrong word, what about chance or "chatunity"?
Anyway, what I mean is if a child is born in a Western stable country with access to good education and a child is born in some unstable war torn country they may have the opporttunity to be more intelligent based upon the chance of where they were born? You know what I mean?
Then again I may be basing intelligence on how well someone does in a pub quiz!

IrishKnight

Generally, children born in the western world to a well of family will do better than someone in born into a war torn country. Opportunity does play a part, like I said, if you have all the "smart" genes but never go to school etc., what use is it?

Somnus

Piste wrote: »

Yes that would be fair to say. The current school of thought is that nature provides a scale of intelligence we can be placed on, whereas nurture decides where on the scale we lie, so for example, someone's genetics could determine they could have an IQ of between 90 and 120, a good upbringing/environment could place them at the higher end of the scale, whereas a poor upbringing/environment could place them at the lower end.

I think that's a very good way to put it.

I definitely think that genetics determines an individuals pre-disposition to learning. There are different types of intelligence though: numerical,spatial reasoning, language etc. I'd imagine that that is strongly related to genetics as people often find a particular area easy/difficult to understand.

Dave!

As described above, genes set the upper and lower 'bounds' on intelligence (or at least, IQ), and depending on your upbringing, you may reach the upper end of that scale or not.

CramCycle

I always understood intelligence to be not what you know but more your capacity to learn/adapt/deal with certain things. If so then certainly genes will play a huge part as regulation of prion folding, memory storage, retrival would be genetic so long as proper nutrition and nurture was provided. Obviously nutrition and nurture dysregulation would lead to dysregulation of gene expression.

There was a great documentary on Channel 4 about Sciences last great taboo, which was the race issue. It involved the reporter interviewing several scientists who had made huge claims about race and IQ levels.

The most obvious thing I took away was that there are huge inherent flaws in IQ tests depending on geographical location and prior education. The best example I seen in the programme was the perception by a few scientists that believed coloured people to have a genetic disposition to lower IQs. One even gave a sliding scale of IQ levels based on continents alone.

It turns out that even though in America, African Americans have lower IQs on average compared to Caucasians, the upward trend in IQ number among the African American community since the end of WW2 means that if you were to just take a like for like comparison, ie equivalent backgrounds for comparison, on average, an African american would have a far higher IQ than their Caucasian counterpart taking there was no difference in Nurture.

My take on it, your capacity is partially inherited but without the proper nurture/stimulation, gene expression which may bring about the ability for a higher IQ could be dysregulated.

Which is more important is more a case by case discussion.

Evanry

nah not inherited

Feargal as Luimneach

Phenotype= genotype + enviromental facors.

IrishKnight

Feargal as Luimneach wrote: »

Phenotype= genotype + enviromental facors.

Ugh, that needs to be expanded a bit

Phenotype = genotype + (inheritable environmental factors + nonheritable environmental factors)

There is a new(ish) field called epigenetics which "is the study of inherited changes in phenotype (appearance) or gene expression caused by mechanisms other than changes in the underlying DNA sequence..."

In other words what you do now, can affect your children.

recedite

IrishKnight wrote: »

In other words what you do now, can affect your children.

That is getting close to Lamarckism.
Epigenetic changes are about inheriting tendencies or characteristics without inheriting a specific gene controlling the tendencies.
You could still be influenced by a gene your grandfather had, without you having inherited that gene. That is different to saying something he did is influencing you.

ligertigon

There are/were a few companies in the U.S. that provided a cloning service for pets. Particularly cats.

One owner got her cat cloned while the origional was still alive. When it grew up, it was totally different to the origional including even colouring on its coat.

http://msnbc.msn.com/id/3076908

Also a good read, though slightly off topic:
http://www.guardian.co.uk/science/2010/mar/19/evolution-darwin-natural-selection-genes-wrong