Genes v. Environment

Election is over and I'm tired of writing political posts- both here and on Facebook.

Changing gears, I wanna' talk about something that a lot of people have widely varying things to say about- the issue of nature versus nurture, genes versus environment, destiny versus development.

As a preface, I'd like to note that psychologists are further and further coming to a consensus that both play pivotal roles in how each person is shaped on this planet, it's the extent to which each plays a role for each individual trait a person possesses.

Let's give an example:

Genetic factors are far more responsible for the color of your hair than environmental factors, however, that's not to say that the environment doesn't play a role at all. While your natural haircolor is hereditary (you will not have red hair without the gene existing in your bloodline), your haircolor can fade as a result of stress, turning white earlier for those under great stress more often. Similarly, baldness may be hereditary, but if you don't wash your hair, you're also more likely to start losing it at an earlier age.
While genes seem to play far larger roles in this realm, the environment does still have its place.

Contrarily, there are traits we possess that are largely environmental, such as our religious beliefs.
If you grow up in a Christian household, you're likely to become a Christian. The same is true of any religion (although the more outlandish the religion becomes, the less likely you are to follow suit, though it's still higher than someone raised in religiously-neutral circumstances.

Psychology has a word phrase for this phenomenon- The Range of Reaction or Reaction-Range- which is simply the extent to which any trait is environmentally determined versus genetically determined. More specifically, it puts environmental determinism into the context of genetic determinism.

To give you a better idea of what this means, let's take a look at a trait like empathy- some people are naturally more empathetic than others because it comes easier to them. However, what happens when we take someone like that and raise them in environments of varying extremes?
To do this, we can assign an arbitrary number scale to the Reaction-Range- let's say -100 through 100, where 0 is perfectly average in every way, -100 is sociopathic, and 100 is total altruism.

No one is born with many traits fully determined in this -100 through 100 range, simply because there are so few traits that are totally genetic. Instead, genetics give you a range within the scale in which you will fall regardless of your environment. The environment merely changes where within that range you'll arrive.
For example, someone is born with a relatively high empathy Reaction-Range rating, somewhere between 10-80. Raised in a pro-charity household where morality is very important, this child would likely wind up closer to 80 (barring other environmental factors). However, raised in an abusive family, the child may grow up with almost completely average level of empathy based on the circumstances of their development.

The wider the range at birth, the more environmentally controlled the trait is. For example, religious beliefs might range from -60 to 60 for someone- far greater than the range for empathy, but still not totally -100 through 100 because genetic factors can determine your predisposition towards extremism of any kind, including religious.

To throw another one at you, we can look at intelligence. If you're born of incredibly intelligent parents, you're far more likely to be intelligent yourself. There are definitely some genetics behind IQ, but if you're not placed in an environment that encourages learning and intellectual stimulation, you will not blossom intellectually. As such, it's always important to balance the environments you put your children in with what you know about their genetics. Some behavior exhibited at birth and during infancy may indicate predispositions, but you can always attempt to influence those predispositions to swing to one extreme or another.

Of course, I'm making up all of these numbers on the spot, because there's no real way to determine what these numbers are, since we can't measure for trait potentiality in an infant and compare it to how they are after growing up. As such, it's a lot of crude estimation and guesswork that accommodates exhibited patterns.

One of the main ways in which the field of psychology studies this is through mono-zygotic twins- identical twins. Identical twins share an absurdly similar genetic makeup, making them ideal to study whether or not genes or the environment is creating the presence of any given trait. This is particularly helpful when the twins are raised in separate households that are relatively different environments.

To give you an idea of how ludicrously interesting and precise this phenomenon can be, examine this case:
http://news.google.com/newspapers?nid=1946&dat=19860619&id=4RoyAAAAIBAJ&sjid=RagFAAAAIBAJ&pg=2229,4466234
Two New Jersey twins, reared apart from when they were just five days old grew up with the same sports interest, hobbies, facial hair, eye problems, hair loss, and most interestingly, career path. They shared almost the exact same career path, actually, going from landscaping to security device installation to volunteer firefighting.
This is certainly the rare case, and it's likely that the twins were reared in similar households, but the main idea is that neither of them had pressure from each other or the same sources to follow the paths that they did.

It actually stirs some concerning questions about whether or not our "free" choices are simply products of our genetic makeup more than anything.

Regardless, it's an incredibly fascinating phenomenon and I just wanted to wax about it for a bit.

-
Waddles

PS- To my psych friends that may be reading this, correct me if I got anything wrong. I was introducing a little personal theory into the traditional knowledge.