Here's the part I am going to summarize. Harris is trying to explain where personality variation comes from. Using controlled studies, evolutionary psychologists and behavioral geneticists (Harris herself is an amateur insofar as a person who synthesizes and clearly explains extremely complex scientific ideas can be called an amateur) have shown that genetics account for approximately 50% of personality. Something between 0-10% of a person's personality is due to his or her homelife. The rest is anyone's guess.
At this point, I have to clarify that when Harris refers to 0-10% of a person's personality being due to his or her homelife, she is talking about one's homelife actually forming personality (a belief promoted by developmentalists). Harris believes that the remaining "rest" is due to the environment in the sense that she believes that it is due to evolutionary factors that work themselves out in the environment. I believe Harris is making the distinction between an environment forming a person and a person bringing his/her genetics and homelife (however inconsequential) to bear on an environment.
Because Harris is an "amateur" evolutionary psychologist, she looks for the answer to the "rest" in evolutionary psychology, not in poetry or philosophy. She presents the need to determine relationships (who can I trust? who can I not trust?), the need to socialize (how do I get along?) and the need for status (how can I survive by getting resources?) as the three factors that make up the "rest" of a person's personality (I'm super paraphrasing). It is in the juggling of these three factors that personality becomes differentiated.
And I more or less think she is right. This doesn't contradict my religious beliefs since I believe one of the purposes of mortality is to experience mortality which seems redundant but does include things like evolution. (I also believe--side note--that genetics is the best defense for free will; as products of environments, we would never get the chance to form individual personalities. Our current environment would mold us instead. I also believe--double side note--that free will is a much more specific instrument than it sounds; I don't think free will means, "Creating my own personality free from outside pressures!" I think free will means, "Being or not being a total dork"--at least from a religious standpoint.)
However, believing Harris is right doesn't prevent me from understanding why she freaks out the developmentalists. (Harris wrote a book called the Nurture Assumption that apparently got the developmentalists very upset). You think the Middle East has problems, check out academic camps regarding nature versus nurture versus evolutionary biology. Yikes!
And Harris, unfortunately (for the developmentalists), is able to point to extremely slipshod trials and experiments run by developmentalists. But this actually brings me to my own (slight) problem with Harris. I am not an amateur evolutionary psychologist. I'm an English teacher. My slight problem arises from inside the gap between evolutionary psychology and the human experience or what humans communicate about themselves.
The developmentalists are upset because Harris states that one's homelife does not form one's personality. It isn't useful to say that parents who go out of their way to attend parenting classes produce better children who become better parents because parents who go out of their way to attend parenting classes are the parents who care about issues of parenting in the first place and will pass on said genes to their kids. (This actually happens in teaching all the time; the teachers who attend the boring required teaching courses often happen to be the best/most dedicated teachers; that doesn't mean the teaching courses are any good.)
Now, partly the developmentalists are upset because their egos are bruised and because there's a whole industry out there built on giving advice to parents to make them better parents (and what? everyone is suppose to just not care?), but I think the developmentalists are upset for another reason as well. (And I think Harris is a little dismissive here; she seems to think that parents are upset about their lack of influence for reasons that have nothing to do with the claim itself.)
Society is filled with conventional wisdom and commonsense wisdom: everybody thinks it and that just makes sense. Now, I'm not a huge fan of conventional wisdom. EVERYBODY thinks that global warming is due to pollution and that, if not stopped, the world as we know it will fall apart at the seams. Yeah, well, it's always something, isn't it?
But I am a huge fan of commonsense wisdom. That is, I do believe that human beings are some of the best people to ask if you want to know what is going on with human beings. So if people have been writing about the impact that parents have on children for thousands of years, I'm kind of going to think they probably do.
Harris argues that this connection between homelife/parenting and personality is relatively new, and she's sort of right (in terms of the obsession and the blame). Ancient Roman fathers may have worried about being good examples to their sons, but I'm not sure how much they blamed themselves if their sons turned out badly. I think they blamed the kid. Or society. In other words, the dependence on socialization in producing decent people has been higher throughout history than dependence on the family.
Except for the nagging problem that you have whole swaths of human beings who for much of history didn't socialize with anyone but their families. I'm not talking about hunters/gatherers where a large percentage of individuals were related. I mean, the pioneers (for one example), sitting out there in some cabin hundreds of miles from nowhere (Laura Ingalls Wilder, anyone?).
Now, note, that Harris and I are talking about two different things. She is talking about the formation of personality and would argue, based on my understanding of her book, that in the absence of an obvious outside social structure, the child will go looking for one. It is vital to the child's growth to respond to something other than ma and pa.
I, however, am talking about influence.
But this is where I feel there is a gap in Harris' arguments. Because that influence exists and human beings talk about it all the time, both historically and contemporarily. People claim influence from their parents. It is easy to say, "Well, you say your parents taught you to be honest, but the fact is you inherited a predisposition for honesty," but when you are relying on those same people to tell you about their personalities, it seems a bit churlish ("a little weird" is my totally unscientific response).
And I think this is where the nature folks lose adherents. I don't think most people are frightened of genetic determinism (why genetic determinism would be any more threatening than environmental determinism is beyond me), but I think there is a reluctance to undermine one's own understanding of one's experience. Commonsense tells us that our personal understanding carries weight. Historical documents assure us that people have always expended energy on their own thought processes. Since I live in my own head and since my personality is (however constructed) my own, I'm hardly going to trust anyone who tells me to ignore my own reason or my own senses. Good grief, Jane Austen didn't. Why would I?
This brings us to my own theory which is the theory of memory. Actually, Harris could probably incorporate my theory of memory into one of her factors (systems), but I separate it because it brings homelife back into the game. I believe with Harris that we tell ourselves stories (explain ourselves to ourselves), but I also believe that those stories, specifically the memories we select to tell ourselves those stories, have tremendous weight. I believe people start creating memory stories (these memories describe me and my experience) as soon as their reasoning skills develop adequately. I also believe that people are drawn to creating a memory story exclusive to their homelife: holidays, vacations, family dinners or lack thereof.
Commonsense (and cognitive learning theories) state that the pathways formed by the selection and repetition of certain memories has something to do with how a person operates. We can change our stories of course, but I find it almost impossible to believe (in terms of commonsense) that a homelife that supplied few positive memories would result in a hugely positive homelife memory story. Gotta work with something. And I also find it difficult to believe that a positive or negative homelife memory story won't influence me in terms of my choices (and I believe that while personality may not be the result of choice but rather the determination that leads to choice, looking at choice is really the only way personality CAN be determined. You can look at a DNA strand or brain scan, but you have to put the owner of the DNA/brain in motion to determine anything about the relationship of the strand or scan to the owner. Otherwise, evolutionary psychology falls into the category of "really, really boring.").
Here is where Harris and I would agree (I think): the homelife doesn't determine what memory story I create or even how much time I focus on creating and repeating a memory story ("time spent" could be genetic). Homelife simply supplies evidence. Other factors will determine what/how I create the memory story but once created, it does carry influence, and that influence impacts my choices outside the home.
Now, it is possible that my desire to create a memory story based on my homelife is a result of experiences outside the home: I come from cultures (American and Mormon) that place a high premium on what happened in my childhood home. But here's where Harris can't have it both ways. If socialization is a factor in our personalities, and if we come from societies which place a high premium on our homelife/experiences with our parents (and most of us do), then we have been socialized to take our homelife seriously which is going to impact our personalities.
And we may not even know it, according to Harris who argues that socialization is largely unconscious. We adopt the patterns of speech and behaviors of our culture in order to conform/operate. This isn't a bad thing; it's survival. If we didn't, we couldn't communicate (and I believe Harris is right that operating successfully as a social animal comes down to communication). However, an invisible force leaves room for other invisible forces. I doubt very much that overt discipline in the home greatly alters a child's personality (unless, as Harris points out, such discipline is relentlessly severe), but I do believe that the influence of memory (what happened to me yesterday; what my parents did this morning and the morning before that; what I tell myself about what happened) does. It just doesn't make any (common)sense that it wouldn't.
I should end by reminding the reader that I am more on Harris' side than opposed to her. I recently took a (very boring) education class where the material instructed me that girls and boys don't always learn information the same way. The material also instructed me not to be sexist and not to harass the boys--oh, wait, that was a different class--and frankly, what the material had to say about male/female learning differences was pretty shallow. But still, I was pleased to know that one is (finally) allowed to say that genes and biology make a difference. It's about time!