Monday, November 23, 2009

Nature vs. Nurture: a Simple Thought Experiment

The nature vs. nurture issue seems to be making its way around again. Not sure why, perhaps the birthday of Origin of the Species, perhaps someone selling their own book or promoting new research, who knows. I must admit, I can't understand why there's any real discussion and my only thought is that we live in a society where people want everything black and white, ones and zeroes.

Well, sorry, but it's not.

For the record, I'd just like to present a little thought experiment I came up with to show the importance of the two. First a disclaimer: obviously we don't fully understand our developmental biology or how our genes turn into, well, us as people (as opposed to us as snarling bags of vicious, thoughtless flesh). But I believe this thought experiment will still be convincing enough to most, regardless.

Thought Experiment: Nature vs. Nurture

Hypothesis: I exist now, in this time, and who I am is a function of both my biology and my environment.

Experimental goal: separation of nature and nurture to study effects individually

Experiment A (nurture): take another, genetically unique, individual and subject them to as similar as possible environmental factors during development from birth.

Comments: this is essentially the case with fraternal twins of the same sex. Few, if any, claims have ever been made that fraternal twins are too similar to differentiate. Of course, it must be noted that their nature will affect their interpretation of their nurture (i.e. who they are genetically, affects how they interact with their environment). This seems obvious when viewed in this common context and is the point of this experiment.

Experiment B (nature): in a century, clone an individual and raise him/her as normal in that century. Compare that individual with the one living today.

Comments: in this case, the nature is exactly the same, barring any changes that happen as an effect of the environment. It seems obvious that the two individuals will be grossly different. Their knowledge will be vastly different, their health may be different, their relationships will be different. It would be surprising if these two individuals would even recognize each other, in a similar way that the same individual a century in our past would not recognize a contemporary clone.

Given these examples, it seems clear to me that both nature and nurture play a crucial part in determining the individual. The way I usually view it (rightly or wrongly) is that, a person is born with a 'potential range' with regards to each trait. For example, on a scale of 0-->100 person J might be born with a potential snarkiness (I believe the actual term used is 'agreeableness') of 35-->65. Where they end up falling later in life is determined by their experiences during life; everything from the first time their parent yelled at them, to their first kiss, to the country they were born in.

Incidentally, something that seems often to be overlooked: The environment plays a multifaceted role in development. The obvious meaning of 'environment' when spoken of in the context of this argument is in relation to the influence of other people, other minds, or macroscopic events such as accidents, on the individual. However, it is well known that the environment also affects the biology through access to needed resources (minerals, vitamins, food in general) for continued well being, and through the influence of hormones, which can affect us at anything from a genetic to a physiological level (yes, there are hormones that are transcription factors). Although the latter is an idea that has only been resurrected rather recently, it is vaguely Lamarkian in principle (remember that name from high school biology?). Only now, we can imagine an actual mechanism for it, in certain cases.

Edwin

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