Home > Nature vs. nurture > Nature vs. nurture – set 1

Nature vs. nurture – set 1

Goal: deal with the myths and set a baseline for a systemic approach in explaining the personality development

If you have read my little story from the practice set article (btw, that was my first piece of fiction — wrinkled as it is, I hope it’ll serve its purpose) you may simply dismiss the story as too fictitious: “There’s no way two identical twins can be so different; we all know that such twins are usually so alike that many share the same quirks and personal behaviors.”

If you think my story is not plausible, please look at a real-life example. Harris opens her book No Two Alike with the story of Laleh and Ladan Bijani — conjoined identical twins from Iran. Identical (and conjoined) as they were, they still had such irreconcilable differences in personality and expectations from life that their wish to get separated was stronger than their genes. Their chances to survive the surgery were 50-50 and ultimately they paid the price with death. Nothing illustrates better the fact that even identical twins are unique individuals with distinct characters, personal views, expectations from life, and separate desires!

Think a bit more about what Laleh and Ladan have to teach us! They share 100% of their genes and the only genetic differences one could have found among them would have been entirely due to errors in copying the DNA when cells replicate. It’s been well established that these errors are infinitesimal and they clearly can’t explain the differences in Laleh’s and Ladan’s case. In addition to sharing the genes, because they were conjoined, Laleh and Ladan also shared their environment. Even the proverbial argument between identical twins that one is older by few minutes than the other doesn’t apply for them — they came out in this world together to the second! They also shared everything, from their parents interaction with them, to the same viruses making them sick as kids, the same school, literally everything! Theirs is as clear a case as one can make that the parental nurturing efforts and in general the shared environment doesn’t make siblings more alike!

It is possible that you might be one of those skeptics that may be thinking: “There is nothing to discuss here; nurture wins hands down; Laleh and Ladan are an isolated exception and in your fictional story it was clear that his mum turned Nathan into a troubled kid!”

I did set the story to make the mum conspicuously looking like having a great influence on Nathan’s behavior. But if we put that aside, I have another real-life, and common at that, example that would hopefully make you rethink: acquisition of a new language by immigrants kids. It is very well-known that immigrant kids speak the language of the environment they grow up in, not their parents language — I face this first hand with my older daughter, her parents’ mother tongue is Macedonian and she was born and raised in Macedonia until she turned almost two and a half years, but today (she will turn six in less than three months) she speaks flawless English with an accent that matches her Canadian friends! In the cases where the kids do retain the accent of their parents or don’t speak the language of the country they’re in, it is either that the kids were brought in a new country very late, when acquiring a new language was not a seamless process for them, or when the family lived in a neighborhood with people predominantly speaking the language of their country of origin.

If you still don’t believe me when I say that the nurture, as I defined it in the practice set article, leaves no long-term marks on one’s behavior as an adult, I wholeheartedly recommend reading The Nurture AssumptionHarris went through a painstaking analysis of the research to date on the impact of the parents’ nurture and generally the shared environment on the similarities and differences between the personalities and behavior of the siblings in a family.

Go on, stop reading this article and read the book first. I’ll be patiently waiting 😉 You can even bookmark this position so you don’t have to start reading from the top!

Seriously — if you don’t give as much as a blink to the surprisingly limited ability of the genes to make two identical twins more alike and the almost non-existent impact of the nurture to shape ones personality, because you know that you are who you are because of what your parents did to you as a kid, then you won’t appreciate the rest of this or future articles and you might as well stop reading now. If I would to argue with you in your current state of mind it would be as if I would be wasting time convincing a deeply religious person that God doesn’t exist.

Ok, so you decided to read on! Excellent — this makes it challenging for me to make sure you get value out of it and I like challenges! 😉

My intention is to draw a picture of a plausible system of organs (see below for a definition) in the brain that is etched in evolutionary possible terms and that can be used to explain how we acquire our personality and how nature, nurture and the random social experiences (noise if you like) work their way through such a system.

By a brain organ I refer to one or a set of areas in the brain, that may or may not be adjacent, that interact together in some (likely complex) way to “implement” a particular feature of our mind. Examples of such organs are the modules of the visual system which are responsible for features like object recognition, depth perception, etc. I strongly believe similar systems are responsible for certain aspects of human personality, like dealing with other people, storing memories of life events, etc.

The system I will elaborate in the coming articles is not going to be new. Harris, in her quest for the perpetrator that made Laleh and Ladan (and even me and you for that matter) so different already identified a plausible scheme that fits the findings and is also testable! The later is crucial for it to be acceptable as a theoretical framework for personality developmentalists and alike — including amateur enthusiasts like myself 😉

My goal is to elaborate the brain system that is responsible for shaping our personality in the next three articles by cracking open each of the three organs involved in it and see how they might work. However, I’d like to take a quick detour here and discuss why a systemic approach in explaining the human behavior is useful and how such an approach can be helpful in explaining some of the findings from recent research as well as in giving you an inkling why you are who you are — if I’m successful, you may even walk away with some ideas what you can do to influence who your kids will become 😉

Let me first explain what I mean by systemic approach! Systems thinking is the process of predicting, on the basis of anything at all, how something influences another thing. Basically it is a way for resolving problems, by treating the “problems” as parts (or features) of an overall system. To illustrate with an example of parent-kid interaction, if a kid is mis-behaving in front of his parents, a systemic approach would make the kids behavior as part of the explanation instead of an external representation of something that is going on between the kid and the parent — e.g. one could ask a question if the kid is reacting to the parent treatment or maybe the parent is reacting to the child behavior; or maybe even a combination of both is going on!

If you have an engineering background, an interesting application of this approach is in the concept of feedback loops.

A feedback loop is a system in which the output of the system is brought back and meshed with the input in a way that can further impact the system’s output in an infinite recursive loop. If you look at my sloppy drawing above, you will see that the output reaches a point T where it is not only presented to the observer, but wired back to the point X where it is merged with the actual input and fed as a meshed input to the box denoting the system. Commonly the point T is some kind of threshold function, i.e. if the output is within a given range, the feedback is not fed back and only when the system produces unexpected results, some kind of delta from the threshold is sent back to the input for calibration. Similarly, the point X is usually a function that combines the input and the feedback in a particular way. For example, in what is usually refereed to as negative-feedback loops, the feedback is somehow extracted from the input to reduce its impact to the output and bring it within the range defined by the threshold. On the opposite end, positive-feedback loops tend to further enforce the input causing the output to spiral out of proportion as stronger and stronger feedback is fed back to the point X, causing a stronger and stronger output.

The reason why I went into this digression is that I believe a similar, though more complicated than my simple single box drawing above, system can be drawn to explain the interaction of a person with their environment, and crucially, the system will have to include the person’s behavior as part of the solution, most probably is some sort of a feedback loop.

One way to draw the picture of the system that Harris elaborated in No Two Alike and I am endorsing here is as shown below:

I won’t be surprised if your reaction is wow … what a complicated system … isn’t simplicity one of the most celebrated factor in any scientific theory ever since the antic Greeks? Well, more and more theories are emerging where complicated formulas or methods are required to explain the experimental data so simplicity may be turned on its head as a wishful thinking and not an intrinsic property of the Universe!

I will elaborate each of the organs depicted in the picture in separate articles and then bring them together in an emergent picture that explains away some of the observations in personality development, but I want to end this article with one thought — unlike my simple feedback loop model before, the personality shaping system is likely more of a complicated network of three (at least that’s what the theory assumes at the moment) main organs that not only have feedback loops themselves, but are also interacting between each other and also converse into a bigger feedback loop with the environment, i.e. the different influence factors like nature, nurture and the random noise of our personal experience, to produce the characteristics that identify us, who we are, how we behave, why do we prefer one thing over another, etc.

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  1. March 2, 2010 at 12:02 am

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