Nature vs. nurture series

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About this page

If you’re new to my blog, welcome! I hope you will find the articles interesting and in particular would be interested to check my thoughts on the age-old debate around the influence between nature and nurture on our personality, i.e. how we’re shaped as we turn from kids to adults. This page is designed to offer an overview on the topic and organize the articles in an easily accessible format.

If you have already read some of my articles, I hope you will still find this page useful in connecting some of the threads in those articles in a coherent view as I try to answer some key questions I believe are important to understand for anyone interested in the topic.

But before we do that, I want to first make an introduction!

The Nurture Assumption

Back in mid 2009 I decided to follow the advice of one of my favorite authors, Steven Pinker – of The Language Instinct fame, and check an author he warmly recommended as someone who has become an authority in personality development with her 1998 book, The Nurture Assumption — that author was Judith Rich Harris.

Given my interest in topics like evolution, psychology and theory of mind and my commitment as a parent to make sure my two daughters have a bright future, I hungrily started devouring Harris’s book — knowing very little what kind surprise was waiting in the wisdom emerging from all that research that Harris so devotedly have compiled in the book!

The book shattered my belief that I play a huge role in shaping my daughters’ personality. Harris have decidedly proven that the kids are not shaped by their parents but something else. The last blow came when Pinker himself said that “the biggest influence that parents have on their children is at the moment of conception”!

Now, I trust the scientific method and I am no hostage to ideology, so I had to concur with the evidence and accept the findings, no matter how bad I felt. However, the fact that Harris went further and tried to put forward a theory of how could the environment shape the kids’ personality made me think if there is any chance to benefit from having a theory that one could try to test! And this is what lead me to start writing articles on the topic.


Sun Tzu said “Know thy self, know thy enemy” and I decided to embrace that in my “thousand battles” with the “enemy” — the group socialization shaping my kids as I stand on the side and watch! Not being formally educated in anything even remotely close to subjects like evolution, behavioral genetics, psychology, personality development and similar, I couldn’t even hope in having a chance to actually test the theory, of course. Therefore, I could do the second best thing, which is this blog 😉

I see myself writing the articles listed at the end of this page as a way for me to better understand the theory, try to put together a model of how the theory could work, and ultimately, do something like a thought experiment to test the model. Whether this will help me personally as a parent is of course questionable and only time will tell — not to mention that life is more complex than any models we may use to understand it — but I still think that the experiment will be useful as a kind of a sounding board for me to reflect on parenting and the issues that come with it.


Without further ado, I’d like summarize the theory I am exploring in my nature vs. nurture articles by reusing some key aspects I already list in one of my articles, before listing the articles in order.

Kids are predisposed to certain behaviors and drawn towards selected interests by their genes – roughly 50% of similarities between siblings is due to genes according to the research, which can (very) approximately be translated as “genes contribute to around 50% of the personality traits of an individual”. This is a very rough approximation as the 50% number makes no sense at individual level, but is rather an average across a large number of people.

Kids come with innate mechanism that allows them to recognize, catalog and constantly update information about the people they meet, read about, etc. Relationships are central to human life and kids already at birth start to exercise this skill by imprinting on their mother’s face, voice, smell, etc. and later they master in using this skill with all people in their lives. Crucially, early on in their life they also build a sense of self and use the relationship system to understand how other see them — sort of like looking into the mirror, except in the human personality case there are many mirrors!

From the moment the self is discovered, two opposite forces influence the kids to turn them into the person they’ll eventually be — the first one is the force to conform to the norms and culturally accepted behavior of the group they belong to, driving their sense of identity; — the second is the force to find a niche for themselves so they can uniquely contribute to the group they belong to, but also out-compete the rest of the peers in their group in the constant race for social dominance, leadership, etc.


To make it easier to follow, I have separate the articles in few groups.

The first group discusses the motivation behind writing the articles:

The second group is a set of articles that are trying to delve in detail into the theory initially proposed by Harris in The Nurture Assumption and later expanded in No Two Alike, along with my amateur attempt to cast a systemic view over our brain and propose a model how could it all work together:

The third group is concerned with the question what can parents do to try to make a difference and let nurture score few points after all?

Of course, you’re invited to check out my other articles in the General category 😉

If you like my blog, I’d appreciate your feedback! You’re also welcome to follow me on twitter at

  1. kima
    September 19, 2010 at 11:12 pm

    Thanks Rachana! This is a first feedback from a reader on this topic and it means a lot coming from a parent!! If you have time, I wholeheartedly recommend reading The Nurture Assumption and No Two Alike from Judith Rich Harris, the two books that disillusioned me of much of the advice I read for how parents should raise their kids and inspired me to start this blog as a way to try to better understand the mechanism behind the personality development from childhood to adulthood.

    Btw, I am impressed with your own blog too! I didn’t have a blogroll before and now I started one with your blog as the first entry along with the freshly pressed page from 😉

    • September 21, 2010 at 9:16 am

      Thanks, it is good to know that I influence people to do something! Pun intended per your TEDchildren post today 😉
      My husband and I had a healthy(please read one-sided) conversation about your article and we are now in the process of shipping Judith’s books.. For now, our debate is off the table until the books arrive!
      Thanks for your public service blog and an honor to be on your blog roll!

      • kima
        September 22, 2010 at 9:55 pm

        Hehehe … I am glad you had fun reading the developments around the TEDChildren idea 😉

        I am looking forward to your — hopefully not one-sided 😉 — feedback once you start reading Judith’s book! I find it unbelievable how little attention they get compared with all those advice books you see in the parenting section, even though Judith’s books are the only ones on those shelves which are backed by research!

  2. September 14, 2010 at 8:37 am

    As a parent of a 2 year old whose is in the “evolution of speech” phase, I am grateful for the Freshly Pressed folks to have recognised your site!! Such an interesting conversation you have here, especially the 3rd point about the opposite forces in your theoritical summary!! Adding you to my blog roll!! Would love to come back and read more, thanks for sharing this wealth of information

  1. September 7, 2010 at 1:18 am

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