The Nurture Enigma – How Does the Environment Influence Human Nature?

Ms Smarty-Pants.

Ms Smarty-Pants

Historical Background

As some of you are well aware, a predominant idea among intellectuals has been that human nature is shaped by the environment, commonly known as the Tabula Rasa or in English, the Blank Slate. This has been the cornerstone of the Enlightenment, the political and philosophical movement of that grew out of late 1600s England and spread throughout the world (although mainly to countries of Northwest European origin). It was an idea that justified social reforms that greatly improved life for most people who were affected by them.

The Tabula reigned pretty much until 1975 when biologist E. O. Wilson wrote Sociobiology, a book that attempted to use evolution to explain not only animal but also human social behavior. Although this book shook things up in Academia it didn’t make that much impact elsewhere. It wasn’t until the 1980s that the reaction against the Blank Slate began to get serious. At this point in time people in the field of behavioural genetics conducted studies on the heritability of things like personality and intelligence that were so extensive and of such quality that they simply couldn’t be ignored. And they showed substantial heritabilities of not just some traits but all of them, something that still holds today. There were some die hard blank slatists, like biologist Stephen Jay Gould, who persisted but most of the resistance to the idea of an inheritable human nature had waned by the mid 1990s (at least that’s my impression).

So the general idea of all nurture and no nature was losing the battle but the vast majority of people were still unaware of this and continued their lives as if nothing had changed – carefully rearing their children during their “formative years” according to “expert” advice, and feeling great when they turned out good, and feeling guilty when they didn’t.  Then in 1998, a text book writer named Judith Rich Harris wrote a book called The Nurture Assumption, summarizing and popularizing the findings of behavioural geneticists, focusing especially on the implications for child development. This was followed in 2002 by psychologist Steven Pinker’s book The Blank Slate, a broad exposé of the whole nature-nurture issue that in its informative and entertaining style became popular in wider circles. People still talk of the formative years even today (I just got a comment from one of them), but by now the tide has irreversibly shifted.

The Post-Slate Situation

So, what does the “new” research from the 1980s, that is now finally beginning to reach public awareness, tell us about human nature? The most obvious part is that nature is a major factor. This is typically summed up in textbooks in the 50/50 rule, claiming that genes and environment can explain about half of the variance each of things like intelligence, personality, psychopathology etc. Which is easy to remember – but also incorrect. This is due to the fact that there is something called measurement error. Most studies are done in a way that doesn’t distinguish this error from the environmental factor. So it’s 50 percent nature and 50 percent environment plus measurement error. Studies that have managed to minimize measurement error typically yield heritabilities for personality traits and similar characteristics around 70 percent. You also have the fact that some of the traits linked to the most important life outcomes, like intelligence and impulsiveness, have even higher heritabilities, around 0.75-0.80.

Equally important – and especially problematic for the adherents of Enlightenment –  is the distinction between shared environment and non-shared environment. It’s the shared environment – family, school, neighbourhood etc – that would lend itself to social reforms. But the research has consistently shown that this factor is very small, often close to zero. As behavioural geneticist Robert Plomin says,

‘Nurture’ in the nature–nurture debate was implicitly taken to mean shared environment because from Freud onwards, theories of socialization had assumed that children’s environments are doled out on a family-by-family basis.

So while there is still a fair amount of environmental influence, it’s not coming from parents, schools, teachers etc. Some people will never accept this; they are too stuck in their political views, they like to blame their parents for how they turned out or take credit for the success of their children. But rational and intellectually honest people will be forced to accept it.

Judith Rich Harris and the Enigma of Non-Shared Environment

But this still leaves us with a substantial environmental influence of the non-shared variety, the unique experiences of the individual, that undeniably affects our personality and intelligence. So what experiences are we talking about?

Oddly enough, 30 years after behavioural geneticists uncovered the importance of non-shared environment, we still don’t know anything about the nature of this influence. This great mystery that goes right to the heart of human nature seems to be uninteresting to both psychologists and the media. Possibly because of the political implications but it might be that they simply lack ideas or intellectual curiosity. After all, personality psychologists – 95 percent of whom identify as liberal – do not praise the Big Five model for all the theories it has generated but for all the consensus it has achieved. Yay…

But one woman, the above mentioned Judith Rich Harris, is actively searching for answers. In a chapter in the anthology The Evolution of Personality and Individual Differences by psychologists David Buss and Patricia Hawley, she reviews the evidence, the old theories and proposes a new one that could explain the nature of the non-shared environmental influence.

Gene-Environment Interactions

This is not to say that she is the first to have attempted this. Some have claimed that parents, school and all that may still be important because of gene-environment interactions: the fact that the same environmental factor will affect two persons differently because of their different DNA. This would mean that the environment believed to be shared is really unique and non-shared and possibly very important.

While gene-environment interactions do occur, Harris argues that it’s highly unlikely for these interactions to cancel each other out. Would an overbearing teacher make one child anxious but the other calm and confident? Even if some children would become angry by such a teacher this would not be the opposite of anxious but rather two expressions of neuroticism. Apart from being implausible, Harris also points to the fact that interactions seem to be rare and most of the documented cases involve sensitivities in which people have the same reactions in varying degrees, not opposite reactions that would cancel each other out.

Even more damning to this theory is the research on identical twins. If things like family was in fact unique and non-shared due to gene-environment interaction for siblings it could not be that for the twins since they have identical DNAs so no interactions are possible. This would mean that parents, school etc would have a profound effect on all people with the exception of identical twins for whom it would mean little or nothing, which would make them fundamentally different from the rest of us. At the same time identical twins have the same size of shared and non-shared environment influence as everyone else. So even though it would be made up of completely different experiences it would still by some happy accident add up to exactly the same size. It just doesn’t make much sense.

Family Interactions

Another couple of theories that both try to save the idea of family as an important influence on human nature, are those of differential parental treatment and birth order effects. While it has been found that parents do treat their children differentially, Harris mentions research on this that showed no effect of this on the children. Instead it suggested that parents do this as a response to the children’s varying behavior. Which sounds very plausible: you would not expect a parent to lose his or her temper as often with a quiet and conscientious child as with an impulsive and emotionally unstable one.

Research has also failed to provide support for any effects from sibling interactions, a very popular theory. Sibling rivalry is something most people can recall from their childhood. It may seem only natural that all that bickering would have some impact. But to date, there is no evidence of that. Identical twins again provide further evidence to the contrary, since they have been found to compete less with each other (as they should according to the laws of evolution). This would mean that the sibling interaction effect would be smaller on them and we again end up with the idea that identical twins have a different shared environment than the rest of us but that it serendipitously adds up to the exact same size.

The Three Systems Theory

Instead of these half-hearted attempts at rescuing any possible remains of the Blank Slate, Harris proposes a different theory based on evolutionary psychology and especially on the observation that traits or mechanisms tend to evolve to solve specific problems and that they for this reason often are largely independent of each other.  So, what problems and what mechanisms?

Well, we know that personality is more malleable in childhood than in adulthood. This is most likely because the brain’s plasticity gradually decreases over the life span. So the environment should exert most of its influence during childhood. This means that we should look for basic adaptive problems that children face. Harris identifies three such problems: how to form personal relationships, how to fit in among your peers, and how to compete among your peers. To solve these problems she hypothesizes that the brain has evolved three mechanisms or systems which she calls the Relationship System (RS), the Socialization System (SS), and the Status System (STS).

The RS is basically an ever-growing database of information on people along with judgments of them based on that data. Since these judgments are used to relate to people they tend to be emotional – who we love, hate, fear, pity and so on. Another characteristic is that the data collected is consciously retrievable. The RS is the base of gossip; we talk about people we have stored information on and compare notes. Although in the modern world this is often done about celebrities that aren’t socially relevant to us.

The SS also collects data but on social categories – male, female, adult, child, rich, poor etc. This is essential information if you want to fit in because you need to know where to fit in – which social categories apply to you. Unlike the RS that looks at personal experiences of specific individuals, the SS generalizes about groups, stereotypes you might say. It’s the basis of our ingroup/outgroup distinctions, according to Harris. But when did we learn about these categories? At no particular time, it just builds up gradually. So unlike the information in the RS, there is no consciously retrievable memory of it.

Finally, we have the STS which collects information about where we stand in comparison to other people in our social category – because that’s where the competition takes place. The reason for keeping track of all the possible status hierarchies – being funny, smart, tough etc – is that it enables the child to find an optimal competitive strategy. So this system looks for things like respect, appreciation and recognition.

So which of these systems is the most likely mechanism by which non-shared environment can influence personality? Although Harris doesn’t say much about why the RS couldn’t do this, we already know that some central relationships in a child’s life are those with family members – which is shared environment and thus of little importance. Still, close friends seems like a possible candidate here… She points out that the least likely mechanism would be the SS, since this is a process by which the social environment (peers) reduce variance in personality as it makes children conform to the people in their social categories. But the STS looks very promising. When a child looks for an optimal strategy for competition, it isn’t looking to conform but to stand out. And if one niche is taken it will have to look for other venues. Like if you’re a big boy who is moderately funny in a peer group of plenty of really big guys but no one who can tell a joke, you may go against your genetic disposition and become the comedian rather than to assert yourself physically.

Evidence

Now that sounds like a plausible theory, but is there any evidence?

Harris agrees that her theory needs to be tested but she does have some evidence too. She mentions the fact that men who were tall as boys grow up to be more assertive and confident as adults. That height in adolescence predicts salary better than height in adulthood. Although she admits that the same thing that makes a person grow fast (androgens) may also be causing their assertiveness. To get around this Harris suggests that we look at relative age within peer groups. One important peer group is that of classmates in school, in which children can differ in age up to a year. This makes for differences in size and maturity that are unrelated to hormones or other biological factors. This relative age effect can be seen in sports where the older boys in groups of selection are picked up by better teams. This may seem stupid if all you do is select players who happen to be older than their peers. But what if being bigger also give them confidence that in turn make them better players?

A study by Dr Chris J Gee at the University of Toronto, published in the International Journal of Coaching Science gives some support for this idea. Gee has followed promising young hockey players over 15 years in order to see if personality can predict success in the sport. According to the study a composite measure of the typical traits thought to be linked to success – self-confidence, need for achievement, competitiveness etc – did in fact predict success. And in regard to the relative age effect common in drafting, Gee writes,

Interestingly, when height and weight (both commonly cited anthropometric indices used when scouting amateur hockey players) were entered into each of the previously mentioned regression models, they failed to significantly increase the amount of variance accounted for.

This strongly suggests that coaches pick the boys who are oldest in their age group, not because they are bigger or have more androgens or something like that, but because they have certain personality traits associated with athletic success. How did they get those traits if all that distinguishes them from other boys is that they happened to be born earlier? It seems to me that Harris’ theory fit these data very well: these boys became confident and assertive through their social environment of peers who couldn’t push them around. This put them on the track to athletic careers, while others who might have been of average size for their age but the youngest in their age group turned to comedy or some other way of becoming popular and getting status.

I think Harris may be on to something.

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30 Responses to The Nurture Enigma – How Does the Environment Influence Human Nature?

  1. JayMan says:

    Great post! This is along the lines of the big expose post on the “environment” that I am planning to write.

    A couple of key points: Harris’s three-system model sounds very interesting, and likely does play some role, but it’s important to note that the role left for true “environment” is likely quite small (possibly very close to 0). You didn’t touch on developmental noise, “random” in-utero fluctuations in development that likely lead to differences between people (that is, as gauged by identical twins raised together). See my comment over at HBD Chick’s on it:

    However, what’s left over, after you’ve accounted for “attenuated heredity” may be what’s known developmental noise. This is “environmental” in the sense that it’s not inherited, but is essentially random and not subject to controlled manipulation.

    Or we think it’s random. See Kevin Mitchell on it:

    Steven Pinker also discussed this in his response to this year’s Edge question.

    Even the technical sense of “environment” used in quantitative behavioral genetics is perversely confusing. Now, there is nothing wrong with partitioning phenotypic variance into components that correlate with genetic variation (heritability) and with variation among families (“shared environment”). The problem comes from the so-called “nonshared” or “unique environmental influences.” This consists of all the variance that is attributable neither to genetic nor familiar variation. In most studies, it’s calculated as 1 – (heritability + shared environment). Practically, you can think of it as the differences between identical twins who grow up in the same home. They share their genes, parents, older and younger siblings, home, school, peers, and neighborhood. So what could make them different? Under the assumption that behavior is a product of genes plus environment, it must be something in the environment of one that is not in the environment of the other.

    But this category really should be called “miscellaneous/unknown,” because it has nothing necessarily to do with any measurable aspect of the environment, such as one sibling getting the top bunk bed and the other the bottom, or a parent unpredictably favoring one child, or one sibling getting chased by a dog, coming down with a virus, or being favored by a teacher. These influences are purely conjectural, and studies looking for them have failed to find them. The alternative is that this component actually consists of the effects of chance – new mutations, quirky prenatal effects, noise in brain development, and events in life with unpredictable effects.

    Stochastic effects in development are increasingly being recognized by epidemiologists, frustrated by such recalcitrant phenomena such as nonagenarian pack-a-day smokers and identical twins discordant for schizophrenia, homosexuality, and disease outcomes. They are increasingly forced to acknowledge that God plays dice with our traits. Developmental biologists have come to similar conclusions. The bad habit of assuming that anything not classically genetic must be “environmental” has blinkered behavioral geneticists (and those who interpret their findings) into the fool’s errand of looking for environmental effects for what may be randomness in developmental processes.

    And finally, perhaps most poignant of all, but greatly underrated, is the fact that that identical twins are not actually genetically identical, but possess subtle differences due to de novo mutations. While behavioral geneticists and others like to ignore these, identical twins are our metric of the effects of heredity. We think we can precisely measure the genetic effect vs “environmental” one by looking at identical twins raised together – anything different between them must be due to environment, so the story goes. But the differences between them could be due to genes, so in reality, we have no idea how big the effect of the “environment” truly is.

    These differences are starting to recognized as being potentially powerful, as seen from the differences of supposedly (but not truly) genetically identical mice:

    All mice are the same, until they’re not | Science News

    Genetic tests that can distinguish between identical twins are becoming availible. This is an underappreciate goldmine in future research into genes and environment.

    Many voices out there (not you :) ) complain about my supposedly extreme hereditarianism, but with all these facts considered, plus the inherent difficulty in demonstrating truly environmental effects (the genetic confound never goes away, even with identical twins), you will understand why I am very hard on environmental explanations. As noted before, this is not to say that they don’t exist.

    Excellent post, this will be a great lead in to the post I’m writing, when I get the chance to do that… ;)

    • Staffan says:

      Thanks,

      Harris does mention noise in that chapter but only in passing, and I’m certainly aware of this possibility. I simply decided to focus on her theory because it deserves some recognition. Whether it will hold up is an open question. The relative age effects are intriguing. Her text also reminded me about what I’ve read about social phobia, how most people can tell exactly when it began, usually in the form of being ridiculed in public. If there is such a thing as a status system it would register such an event as of major importance, and perhaps compel the person in question into a strategy of keeping a very low profile.

      But sure, noise and other non-social influences seem pretty neglected. If I remember correctly, twins also develop asymmetrically due to pre-natal competition, and a lot of twins die at a very early stage. I’m in no waying ruling out the possibility that social experiences have zero influence on our psychological characteristics.

      But good luck selling that idea : ) Even smart people have an intuitive dislike for it. As a bit of a Jungian, I always point out that people understand and remember things like stories, and if we take out the social influence we have very little to work with when we make up the story of how we came to be the way we are. So let’s hope Harris is right : )

      • Sisyphean says:

        If we take out the social influence we’re left with genealogy as the major genesis for the story for how we came to be the way we are. Long ago it was standard to understand that your talents and abilities were part of your line but in the modern world people are encouraged to believe that they are unique and special, the link to the past has been severed.

        ~S

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  3. Staffan says:

    Yes, ancestry is no longer PC for obvious reasons – another reason why modern intellectuals can’t tell good stories.They should really ban Tolkien too for his racist Fallohides. Or any stories of fairies, trolls, vampires etc that so obviously present the idea of groups of humans being innately different from each other.

    But they allow it because their dirty little secret is that they too would be bored to death in a culture based on their way of thinking.

  4. Gottlieb says:

    People and nurture – boyz , like the idea of determining the environment ” as if I ‘m in a hypothetical situation , I can act in different ways , I mean , I can become more outgoing , I can be psychotic , or can calm down .” They start from the assumption that the environment changes and you relentlessly adapts to it . It’s almost as if we had not willingly, or
     the” extremism ” inverse, nurturism extreme. I think the possibilities of responding to the environment , it is entirely up to humans and therefore is genetic. Nobody is totally introverted , even the most introverted tendencies can be very remote for extraversion , at specific times . All the shy keeps an extrovert insecure within themselves , all the introvert has two personalities and almost always , the inner personality is more outgoing (and speaker ) than the outer personality .
    We all have nano – variations within each personality trait and cognitive abilities . In fact , we have a genetic conditioning to react similarly equal , because of the increasing hardening of our brain plasticity , that you said , is greater during childhood . Creative people , for example , tend to be extroverted and introverted at the same time, suggesting greater plasticity or longer plasticity , the childlike style .
    At the most, the only environmental factor that can cause changes in human behavior that I have news for now is pollution, which some say is responsible for the largest number of cases of autism. At the most, the pollution is caused by humans, 30-40% anthropological factor, have parents with autistic genetic predispositions (internal variation that I always speak) to have offspring under these conditions (mother with high testosterone have child in polluted environment, high testosterone that was to result in a nerdishs-style or brainiac introverted kid results in a child with autism). Over 30-40% of genetic factor?

    • Staffan says:

      “Creative people , for example , tend to be extroverted and introverted at the same time, suggesting greater plasticity or longer plasticity , the childlike style .”

      Yes, neoteny might cause some people to retain more plasticity over their entire life and for that reason even be more affected by the environment. Although it must be rare since statistical studies show only small changes over time in adulthood. Which begs the question: are personality traits that increase over time, like emotional stability and conscientiousness linked to an (in)ability for adults to learn new things? After all, humans have long childhoods and the evolutionary reason for this would be that we can learn more that way.

  5. Gottlieb says:

    I saw a documentary that talked about the greatest human revolution that made ​​us what we are today. The onset of adolescence, how it happened? (probably selection is not?)
    Funny, we are living longer only because of the advancement of medicine or by genetic changes? Creative people seem to infant behaviors throughout their lives. What would be the self functioning autism, an exaggerated extension of this trend to become more kids?
    Perhaps the same lack of gene that makes us righties can explain the brain immaturity or neoteny of creative people, who seem to be mostly ambidextrous. The lack of genes for right-handed hand, explains greater brain plasticity and text on the blog of Hbd Chick talks about genetic alterations cicladiano period when sleep is disturbed. We know that the most creative periods tend to have heterogeneous sleep with periods of insomnia and great drowsiness.
    It is part of my theory about anthropomorphism, the true individual, be independent of nature. I believe that smarter people tend to believe in nurture, because they themselves are more likely to be affected than others.
    I do not believe in brainwashing, but also phenotypic similarities of genetically familiar individuals. We have two people who never met in life, one lives in California and another in New York, both are liberal and believe in nature. Or they are even more affected by the nature and tend to have a capacity of more individual interpretation than systemic.

    • Staffan says:

      “It is part of my theory about anthropomorphism, the true individual, be independent of nature. I believe that smarter people tend to believe in nurture, because they themselves are more likely to be affected than others.”

      I suspect this too, although I would say modern people rather than smart – it’s very easy to get into the habit of thinking of them as smart, but Japan is not as modern as Denmark but it has a significantly higher national IQ.

      You may of course think of the plasticity of modern, Northwest Europeans as a form of intelligence, given the intellectual achievements of these people – who I’m so fed up with : ) But I think creativity is a closer match.

  6. Gottlieb says:

    ”it’s very easy to get into the habit of thinking of them as smart, but Japan is not as modern as Denmark but it has a significantly higher national IQ.”

    IQ is not the unique way to measure and to think about intelligence. I believe that the IQ is good to measure ”technical intelligence”, or abilities to learn linear and mechanical thinks (Convergent stuff). Engineers have higher iq than average creative people, they are good to learn convergent thinking. Creativity relate, in my conception, to verbal iq and verbal iq with other components like visual spatial (to ‘visual arts’ obviously) or other.
    Remember, creativity link to psychopathology and link negatively with higher iq. The larger incidence of extreme personalities on whites than asians be related with lower average IQ of the first group than the second.

    • Staffan says:

      Tomato, tomahto. Intelligence is convergent thinking, creativity is divergent thinking (that is somehow useful). We don’t need to call every ability intelligence.

  7. Gottlieb says:

    Modern people, in my opinion, are more unconscious smart than conservatives. What they think is only the super reality, without religions, without moral laws or anything concrete thinking build by humans. But super reality is non-adaptative. I speak by myself.
    I mean, the way they think and act is correct by the idea of evolution aimed at transcending nature itself ( which seems born for this ) . However , most are as stupid as the average conservative, but conservatives in the world , 2014, in which we seem smarter because they are adapted to millennia . Therefore , artificially , ordinary liberals seem even more stupid than they really are because the project they foolishly believe , is bankrupting the naked eye . ( because socialism is a weapon used by the elites to deceive the masses , unfortunately) . However , they are certain that for example, a guy wants to wear a feminine outfit. It is an individual and modern thought that is not present in most of humanity . When it is , is explained by cultural reasons . The interesting individual or super reality thought is that explanations for behaviors outside the box are not necessary . Nihilism is another strong trend that defines individualism .
    I’m of the theory that super reality reshapes human behavior, impulsiveness ending with the idea of ​​impulse control. When you are questioning that life is too sensitive, you shall live intensely every day, hence the liberal impulsivity. Impulsivity low IQ is genetic, impulsivity modern caucasian liberal (and its similar expressions in other groups) is conscious and therefore epigenetic. Liberals tend to be more impulsive than conservatives earn more but it seems that, at least in the U.S..
    Being smart unconsciously, would live by their epigenetic predispositions (especially liberals), not necessarily being more intellectually intelligent but anthropomorphically advanced than the conservative, basically rejecting the entire human collective-cultural subjectivity and living the super reality without God, no rules of conduct that leads to paradise without literally interpret the bible or the Koran, anyway …

  8. Staffan says:

    “Modern people, in my opinion, are more unconscious smart than conservatives. What they think is only the super reality, without religions, without moral laws or anything concrete thinking build by humans. But super reality is non-adaptative.”

    It’s the world of ideas and principles detached from the social environment. This is perhaps a correlate of the guilt culture. But they replace the conservative traditions and values with their own – science and political correctness. This is probably because modernity has become so popular that people who are not so modern join in and then fall back into their old habits but giving these habits new names. Although they are probably still slightly more intelligent than conservatives.

  9. Gottlieb says:

    As well, I did not understand that old habits they rename with different names?
    I do not know if you understand, I think that the human being is moving inexorably to the modern type we found. Human evolution, I call philosophically of anthropomorphism, fits perfectly with satanists ideas, LOL.
    ‘Do what you want.’
    Athens, Rome, Mesopotamia, and who knows how many others. The human being and especially the white man, because of his tendency toward individualism, evolves exactly … transgender (LOL), for example.
    What makes a human community be so different from a non-human community?
    I think it’s individuality. In nature, this principle is costly and is only maintained if perchance have any direct advantage. When you master the environment we live in, we started walking to specialize functions. The more specific it is a function, it is a more craft, more individual function it becomes.
    I think.

    • Staffan says:

      It’s hard to make predictions of this kind. I personally suspect that the modern people of Northwest European descent may be unable to compete. Most likely it was guilt culture that enabled their individualism, people policing themselves. That trait probably needed geographic isolation to protect them from being exploited. But we are all increasingly interconnected now and will be in the forseeable future. And they don’t make babies.

      • Gottlieb says:

        I do not believe that Europeans are not eligible to compete. I believe they, once again forged a brilliant civilization. Every great system becomes vulnerable. Europeans reached the apex (not to mention the presence of foreign groups, previously’m disregarding this fact, despite being very important) and do not see any more predator. They exist, but a good indirect predator, is also good at camouflage. The Europeans have a very direct game, true, based on direct competition. Individualism selected honesty. Competitors, predators indirect, immigrants, blacks, Jews, Asians few opportunists, are all based on the game of omitting a truth or double speaking. They are not generally susceptible to dishonesty, especially if it’s good for the group.

      • Staffan says:

        All empires fall, sure, but this is different. This is people policing themselves and then letting strangers into their house and telling them to do the same. As soon as Sweden introduced mass immigration from the Middle East people instantly became less interested in paying tax – less civic-minded. Next step is increasing corruption. I don’t see how we can defend ourselves since the majority is unaware of what’s going on even with the predator in their face. Isolation seems to be the only protection.

  10. Matt says:

    Trait-rank (where a person falls in a trait relative to others in their population) is generally probably highly heritable.

    Where heritability may be lacking is often going to be more in the mean and standard deviation of the trait from one generation to the next (see obesity and bmi). This may not show up that well in twin studies.

    Also, while traits may be highly heritable, they may not be necessarily very predictive.

    For many cases where prediction is desirable and useful, individual situation and past experiences which don’t really cohere to traits may loom so large that making strong prediction from traits may not be possible.

    E.g. someone who has had bad business deals in the past and who is in a financially precarious situation (due to circumstances beyond their control) may show low “trust” in certain financial situations in a way that could not be predicted from any interaction of any traits they hold.

    This kind of information wouldn’t show up in something like the Big 5, which essentially asks people to imagine themselves in abstracted situations or describe themselves in a way unrooted from situation. There is a good reason for this, because it isn’t “personality” or a psychological “trait” in any sense! But could be very important for how people actually behave and respond in given situations.

    I’m sure you are all well aware of this, but we can often get too bogged down in the argument as to whether traits are highly heritable or not based on an unspoken assumptions that where there is large variances on certain variables, they must be due to large trait differences, or that even in theory they can be explained 100% by trait differences. It’s not the case “traits” are the only game in town, so if traits are 100% genetic it implies outcomes are 100% genetic, etc.

  11. Staffan says:

    The change over generations is probably hard to even study since we’d have to have new tests with new criteria for validity. But there doesn’t seem to be much change over a person’s life span, at least not from early adulthood and on.

    But sure, predictive validity is a problem in personality psychology, especially when you look at broad factors like the Big Five and at the individual level. Given how flawed that model is I still find it interesting that there is some group-level predictive validity – like how people who throw tantrums at 6-7 years of age will divorce more often in their early thirties. But to have just one guy take a test and be able to conclude his level of trust in a business setting, that’s probably impossible, unless we make up some phony trait of business trust of course, but that would be circular.

    I’m not entirely sure what you’re getting at here but besides the concept of heritability there is the fact that this variable is not always corresponding with a specific behavior. We know that there are strong situations that will override personality completely. A serious of bad business deals may amount to something similar, resulting in a behavior that is in contrast to what his or hers personality would indicate.

    Another thing is that a trait like openness may be affect how well we adjust to the environment. If you think of it in terms of life history, we have the variable time period within which we choose strategies and perhaps revise them. Some are neotenous that way others probably fixed strategists. Openness-type traits may refer to a neurological or functional plasticity which makes other traits less heritable, as Gottlieb pointed out earlier.

  12. Matt says:

    But there doesn’t seem to be much change over a person’s life span, at least not from early adulthood and on. In terms of where a person falls in the distribution, probably not. Large absolute personality differences by age seem to exist after early adulthood, but a person who has say, a high degree of aggression, at 25 seems likely to have the same degree of relative aggression related to his peers at 50, adjusted for how wide that distribution is at 30 (where it may be more constrained).

    I’m not entirely sure what you’re getting at here I may not be expressing myself well here.

    I’ve noticed there is often an equation of “the environment effects people” to “the environment effects people through changing and determining their traits”, under a worldview where traits are the dominating factor leading to outcome.

    But there are other ways for the environment to matter that don’t cohere to traits, and traits can be trivial in actual outcome, whether they’re heritable or not. Experiences for instance are carried with people, but they are clearly not traits and no trait model could include them successfully.

    This is a little tangential to your discussion, but I’ve noticed arguments with people who propose environmental influence tend to get hung up on the idea that if environment doesn’t influence traits, then it has no influence, where the reality is past and present environment may have a very high influence but not through any trait pathway.

  13. Staffan says:

    I’m not sure something like aggression would change so much. More likely the expression of it could change. Children fight a lot, senior citizens don’t, but they can be pretty grumpy. I guess it may be a matter of definitions – you might argue that grumpyness is constrained aggression.

    There was a big study looking at thousands of people over a 4-year period who found very little, even for single individuals facing adversity. Here is from the abstract,

    “Intra-individual personality change is generally unrelated to experiencing adverse life events and is
    unlikely to be economically meaningful. Like other non-cognitive traits, personality can be
    modeled as a stable input into many economic decisions. ”

    More here: http://ftp.iza.org/dp5943.pdf

    Studies spanning over longer period find a bit more change but always in the typical maturation pattern – less impulsivity, more conscientiousness etc.

    “But there are other ways for the environment to matter that don’t cohere to traits, and traits can be trivial in actual outcome, whether they’re heritable or not. Experiences for instance are carried with people, but they are clearly not traits and no trait model could include them successfully.”

    Sure, I mean behavior is one thing and personality another. The environment is a determinant of behavior, no argument there. This has been shown very clearly in Sweden which has had a very restrictivie alcohol policy. During strikes when supply almost vanished so did violent behavior until the strike was over. And when we joined EU we saw violent crime rise with some 30 percent because of more alcohol. The environment can be very powerful.

  14. Gottlieb says:

    ”All empires fall, sure, but this is different. This is people policing themselves and then letting strangers into their house and telling them to do the same. As soon as Sweden introduced mass immigration from the Middle East people instantly became less interested in paying tax – less civic-minded. Next step is increasing corruption. I don’t see how we can defend ourselves since the majority is unaware of what’s going on even with the predator in their face. Isolation seems to be the only protection.”

    Yes , the isolation that must happen by geographic location but I also believe , through an active political organization . You simply can not convince much of the liberals that believe fundamentally important parts that are very wrong , not all of course. I do not think liberals are wrong , I believe they are so domesticated that were born at the wrong time . They are man without ears up , they do not come predators . Are an extreme behavior , we the truth seekers , tend to be the balanced type , which shares much with conservative ideas as to liberal ideas . It is the post- selection selection. First you have a great selection that makes a few dominant phenotypes . After the environment changes, and makes these non-adapted phenotypes . So , the ‘nature’ eliminates most of these maladaptive phenotypes and more adapted inherit the earth again . The hbd population seems to be predestined or at least ideally predestined to inherit the postmodern world because they are much more intelligent than the average .
    The best eugenics is disgenia or dysgenic culture. You are literally separating the best from the worst grain , the only problem or severe sequelae of any selection is that some phenotypes inexorably badly adapted , but so are more evolved , in my opinion , they should be physically held . Aspies for example.

    • Staffan says:

      True, liberals think of themselves as reasonable and balanced but look at history and look througout the world – they are pretty extreme and destructive. That said, there are liberals who want a respectful dialogue, like Jonathan Haidt, Jon Stewart, and a woman named Sally Kohn, who I hadn’t heard about before,

      I think some HBDers might be close to aspies, with their maps and their truth-telling. And perhaps that frame of mind is closer to how Enlightenment started out before it went mainstream.

  15. Gottlieb says:

    I’m not too convinced that aspies would be more like HBDS since at least the Wrong Planet website, this first group demonstrated overwhelmingly liberal in their political and cultural beliefs. I believe yes and is extremely likely to be, that we have more autistic traits than average. However, these features in combination with the spectrum of psychosis. The Aspies are on the precipice of the functionality of autistic-like traits, where the cognitive expertise goes to the extreme of this continuum. The more specialized a kind, he will be more vulnerable. Likewise the less specialized, most vulnerable. In summary, any extreme, in competition, it will be poor.
    Liberals are an experiment of human nature, it did not work.

    • Staffan says:

      Most people on any forum are relatively young Westerners and for that reason liberal. It may well be that most aspies are liberals but that which characterizes HBD could still be an aspie type way of thinking, especially the truth-over-harmony trait. I don’t think psychosis comes into this much; those people aren’t into science but have fixed ideas that they will pursue by pure intuition or by pseudo-science. Then there are people who may want to use HBD for their own political purposes but they are neither aspies nor liberals.

      • Gottlieb says:

        Some psychosis is necessarily to ”divergent thinking”. Idealism and truth seekers without some psychotic traits is equal a naivety.
        Very empathetic people dislike to say ”blacks, on average, are less smarter than whites and asians”, HBDers not. :o

  16. Gottlieb says:

    Well, when i talk about ”psychosis”, i’m not referred to ”schizophrenia or bipolar disorder” but to degrees of psychosis. People which are strong psychotic lost your contact with the reality but have also strong creative potential. Comedians for example tend to have higher, but not extremely higher, psychotic traits or levels. They are the same time, more creative, occasioned by their rational dissociative potential and more realistic, because they are more affected by environment (neoteny and infantile brain again). The psychosis in humans related with instinct more developed or irritated, aspies and similars tend to be more naive than average. They are affected by environment more based on quantitative than qualitative ways. Psychotic and schizotypes are less affected by environment (quantitative), but with more chaotic (diverse) ways. Obvious, i think about selection to liberals to autistic online community, but the rationalism with the naivety related also with neurotypical liberals. But we talk about the larger autistic community on web.
    Many autistic people also are more psychotic. Well, they are very internally variable, but the autistics with lower psychotic traits will be more naive and accept the humanistic discourse, i think.
    HBDers, in my opinion, are more psychotic than average, the simple fact that we are completely against the ”common sense” today prove which this psycho-component is essential to our revolt against the system. The difference that is we are rebels with a cause.

  17. […] split, I noted that much of the 50% not ascribed to genes is in fact measurement error. Staffan had a post on that matter (emphasis […]

  18. […] might be boiled down to peer influence. Staffan did a nice recap of Harris’s theory (see The Nurture Enigma – How Does the Environment Influence Human Nature? | Staffan’s Person…). We all have heard of peer pressure. And indeed, peers seem to be an important force when it comes […]

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