@ Potyondi [On Heredity]

[Janus]

[Source (http://www.revolutionaryleft.com/lofiversion/index.php/t5574.html)]
Is there an inherent nature of man?

[...]

Is he born... [g]reedy [or] selfish or altruistic and selfless? Heredity is an important factor in determining the preponderance of specific temperamental-variants. ¹ (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16534505&query_hl=18&itool=pubmed_docsum) ² (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16202396&query_hl=24&itool=pubmed_docsum)Or is he neither, a tabula rasa (blank slate) as Locke described.John Locke propounded the "tabula rasa" theory before the onset of modern behavioral genetics; it corroborated his promulgation of "inalienable rights".I believe that men are born with no inherent nature whatsoever. Men possess a genetic-predisposition toward aggression. ¹ (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15795710&query_hl=40&itool=pubmed_DocSum) ² (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2029601&query_hl=45&itool=pubmed_docsum)To some extent their personalities are determined by their genetics, but their attitudes are completely independent of that. The attitudinal-disposition of an individual is partially determined by their genetic-constitution. ¹ (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16354504&query_hl=31&itool=pubmed_docsum)If I separate two identical twins at birth and raise them in completely different conditions, they will be completely different people. Identical twins raised in separate-environments possess similar temperments. ¹ (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16176717&query_hl=1&itool=pubmed_DocSum) ² (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2347836&query_hl=4&itool=pubmed_docsum)

[Fade the Butcher]

Check out the video in this thread.

http://www.thephora.net/forum/showthread.php?t=6132

[Jonathan]

Sorry for the interuption but...

Identical twins raised in separate-environments possess similar temperments. ¹ (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16176717&query_hl=1&itool=pubmed_DocSum) ² (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2347836&query_hl=4&itool=pubmed_docsum)

...Of the two examples which you've given, both of them deal with infants or infants and toddlers. That doesn't leave a whole lot of opertunity for social conditioning so the examples are biased towards the genetic inheritance debate. While I have no academic evidence to back myself up with, I imagine that the disparity between twins raised seperately would be much greater by the time they're in their teens and so on.

[Fade the Butcher]

Chico is right. Numerous studies have shown that identical twins raised in different environments are more alike than adopted siblings raised in the same household. Furthermore, we know that the environment is more of an influence in childhood than it is later in life. People become more like their parents across time, not less.

[Petyr Baelish]

Sorry for the interuption but...



...Of the two examples which you've given, both of them deal with infants or infants and toddlers.

What of it? Environmental impacts on genetically influenced traits are actually strongest during childhood. The heritability of intelligence, for instance, increases with age as environmental influences, which are usually transient, become progressively less important.

While I have no academic evidence to back myself up with

You never do, which I would imagine says more about your intelligence than anything else. Even if you aren't fortunate, as some of us are, to have access to a world-class library, the internet is a veritable treasure trove of scientific information if you can spend a few minutes looking.

I imagine that the disparity between twins raised seperately would be much greater by the time they're in their teens and so on.

You're wrong as usual.

[Janus]

...the disparity between twins raised seperately would be much greater by the time they're in their teens and so on. The temperamental-similarity of identical twins is progressive. ¹ (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=3434126&query_hl=30&itool=pubmed_docsum)

[Jonathan]

Furthermore, we know that the environment is more of an influence in childhood than it is later in life.
I would have thought it was the other way around - the longer you live in the environment, the more it is acting on you, while your genes are there from the start. Is it the case that genes take longer to take effect, only kicking-in in later life? Is there an explanation (that's known) for this ?

The heritability of intelligence, for instance, increases with age
[Assuming you're big up on studies of intelligence, saving me the bother of looking this up on the net]Can you tell me what happens to children who have one very intelligent parent, and one 'stupid' parent? Do the offsprings' intelligence average out or wha exaclty?

You
Personally?

never do
On this issue itself or ingeneral?

which I would imagine says more about your intelligence than anything else.
I would have thought that it said more about my level of interest in the subject...maybe that conclusion is down to my level of intelligence too.

You're wrong as usual.
As usual? As usual for what?
UP, for someone that I don't think I've ever communicated with before, would I be right in saying that your reply was something of an 'over reaction'?

The temperamental-similarity of identical twins is progressive. ¹ (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=3434126&query_hl=30&itool=pubmed_docsum)
Thank you, you've been most helpful. If you fill me in on the other questions in the post(relating to heredity), that'd be great.

[Janus]

Is it the case that genes take longer to take effect, only kicking-in in later life?The phenotypic-aspects of some traits are not fully-developed until later in life; "pubescence" is an example of a "late-onset" phenotype.Is there an explanation (that's known) for this ?It is known as "ontogeny (http://en.wikipedia.org/wiki/Ontogeny)".

[Fade the Butcher]

I would have thought it was the other way around - the longer you live in the environment, the more it is acting on you, while your genes are there from the start.

We know from various studies that humans become more like their parents over time. The effects of environment are much stronger in childhood when the organism is still developing but wash out considerably in later years.

Is it the case that genes take longer to take effect, only kicking-in in later life? Is there an explanation (that's known) for this?

I'm just beginning to explore the subject myself, but from what I gather genes can switch on and off in response to environmental stimuli.

[Jonathan]

We know from various studies that humans become more like their parents over time. The effects of environment are much stronger in childhood when the organism is still developing but wash out considerably in later years.
I don't mean to heckle you but:
What if both parents are vastly different?
In my experience, boys tend to end up like their fathers, and girls like their mothers(I thought this had something to do with fathers and mothers being the main "role models" for their sons and daughters respectively).
Is this the case? If so, is this mainly the result of genetics?

I'm just beginning to explore the subject myself
Take your time...keep us posted ;)