It has long been known that children from homes at the lower end of the Socioeconomic spectrum do more poorly on intelligence and achievement tests than well off children. These less fortunate children also tend to do more poorly in school, have increased learning and behavioral disorders, and increased drop out rates. A great deal of effort has been directed toward understanding these differences, and mounting evidence points squarely at the effects of environmental deprivation. You might think that this conclusion is a “no brainer,” but, for some time, it has not been so clear. Some researchers have found evidence to implicate genetic factors for these differences. Over the last several years more conclusive evidence is pointing at environmental rather than genetic determinates.
Last week I discussed some ground breaking evidence from behavioral geneticists that asserted that environmental determinates play a crucial role in mental ability scores, but only for Low Socioeconomic Status (LSES) children. I noted that “For [LSES] children, the environment remains the key variable associated with differences in mental ability. Perhaps as much of 70% of the variance in mental ability is attributable to the shared home environment. While for [High SES (HSES)] children, genes become the predominant variable associated with the differences in mental ability scores. Environment still plays a role but much less so. Smart parents have smart kids unhampered by environmental constraints.”
Questions have persisted for quite some time as to what factors influence these differences. Research to date has implicated variables like parental attention, number of words spoken in the home, access to books, and familial stressors; however, the actual physiological or anatomical mechanisms (e.g., neurocognitive processes) that result in these discrepancies have remained elusive. You see, many factors have been found to correlate with the underachievement of LSES children, but not until a study by UC Berkley Neuroscientists, did we have conclusive direct evidence of how these factors may actually produce neurological differences that play out in these cognitive, achievement, and behavioral gaps.
Scientists at UC Berkeley’s Helen Wills Neuroscience Institute and School of Public Health report in a study published in the Journal of Cognitive Neuroscience that typically developing nine- and ten-year-olds who only differ in terms of SES, have detectable differences in prefrontal cortext responsiveness. The prefrontal cortex is the part of the brain that is known to be involved in problem solving and creativity.
In a press release about this study it was noted (Sanders, 2008):
Children of high SES show more activity (dark green) in the prefrontal cortex (top) than do kids of low SES when confronted with a novel or unexpected stimulus. (M. Kishiyama/UC Berkeley)
Brain function was measured by means of an electroencephalograph (EEG) – basically, a cap fitted with electrodes to measure electrical activity in the brain – like that used to assess epilepsy, sleep disorders and brain tumors.
“Kids from lower socioeconomic levels show brain physiology patterns similar to someone who actually had damage in the frontal lobe as an adult,” said Robert Knight, director of the institute and a UC Berkeley professor of psychology. “We found that kids are more likely to have a low response if they have low socioeconomic status, though not everyone who is poor has low frontal lobe response.”
Previous studies have shown a possible link between frontal lobe function and behavioral differences in children from low and high socioeconomic levels, but according to cognitive psychologist Mark Kishiyama, first author of the new paper, “those studies were only indirect measures of brain function and could not disentangle the effects of intelligence, language proficiency and other factors that tend to be associated with low socioeconomic status. Our study is the first with direct measure of brain activity where there is no issue of task complexity.”
Co-author W. Thomas Boyce, UC Berkeley professor emeritus of public health who currently is the British Columbia Leadership Chair of Child Development at the University of British Columbia (UBC), is not surprised by the results. “We know kids growing up in resource-poor environments have more trouble with the kinds of behavioral control that the prefrontal cortex is involved in regulating. But the fact that we see functional differences in prefrontal cortex response in lower socioeconomic status kids is definitive.”
These scientists suspect that “stressful environments” and “cognitive impoverishment” are responsible because in previous research on animals, these very factors have been shown to affect development of the prefrontal cortex. “UC Berkeley’s Marian Diamond, professor of integrative biology, showed nearly 20 years ago in rats that enrichment thickens the cerebral cortex as it improves test performance. And as Boyce noted, previous studies have shown that children from poor families hear 30 million fewer words by the time they are four than do kids from middle-class families.”
These factors lead to important differences in brain functioning. As the lead author noted in an interview: “Those from low socioeconomic environments showed a lower response to the unexpected novel stimuli in the prefrontal cortex that was similar to the response of people who have had a portion of their frontal lobe destroyed by a stroke.” (Sanders, 2008)
One question that arose in my mind as I reviewed this paper was whether something other than SES was responsible for this effect. I asked Dr. Robert Knight this question:
“The HSES and LSES kids differed in both prefrontal cortex response level and standard scores on intelligence test subtests [Intelligence data was also collected as part of the study. On multiple incidences LSES children obtained significantly lower subtest scores than HSES children.] Is it not possible that genetic traits (i.e., lower IQ) might be responsible for the lower prefrontal cortex activity level, not SES?“
Dr. Knight referred this question to the led author, Dr. Mark Kishiyama, who responded in personal correspondence:
“This study was designed to reveal the effects of poverty on brain function rather than to identify specific causes. While we cannot rule out the potential effects of genetic factors, on the basis of prior evidence, we proposed that the primary influences were environmental (e.g., stress and a cognitively impoverished environment). There is considerable evidence in both human and animal studies indicating that stress and environmental factors can contribute to disruptions in brain development. In addition, we believe that these effects can be reversed with early childhood interventions (see also Raizada & Kishiyama, 2010).“
The implications of these findings are profoundly important and grim. If we accept these results and do nothing, then we all are complicit in perpetuating the cycle of poverty. We know that there are important differences in how LSES and HSES children are raised. Education, training, and intervention programs must focus on narrowing this gap. I contend that parent education programs like Baby College administered by the Harlem Children’s Zone must must be closely examined and if shown to be effective, replicated on a broad scale. I also contend that programs like Early Head Start and Head Start should focus their efforts on proven strategies that close these gaps. This is essential in order to build a just society whereby we all get a more fair shot at rising up and contributing fully to society.
Kishiyama, M. M., Boyce, W. T., Jimenez, A. M., Perry, L. M., and Knight, R. T. (2009). Socioeconomic Disparities Affect Prefrontal Function in Children. Journal of Cognitive Neuroscience. 21:6, 1106-1115.
Sanders, R. (2008). EEGs show brain differences between poor and rich kids. UC Berkley Press Release.
Tucker-Drob, E. M., Rhemtulla, M., Harden, K. P., Turkheimer, E., & Fask, D. (2011). Emergence of a Gene × Socioeconomic Status Interaction on Infant Mental Ability Between 10 Months and 2 Years. Psychological Science. 22(1) 125–133.
Several of my latest posts addressed evidence that challenged some of my long held beliefs about the relative value of parenting style on child outcomes such as mental ability and happiness. In Ten Best Parenting Tips: But does it really matter? I challenged a recently published study in Scientific American: MIND touting the “ten best” parenting tips. The relationship between parent reported child outcomes and parenting behaviors was measured using a correlation coefficient. The author did not, however, control for heredity. It is well known that genes play out in the expression of personality type and a broad array of complex behaviors. So why would it not play out in the happiness, health and functioning capacity of children? If you don’t control for heritability is it not possible that well functioning adults might just pop out well functioning kids? Well it certainly is! And might we wrongly attribute parenting style for something actually under the influence of genes? Yes indeed!
I then explored Does Parenting Style Really Matter? and suggested that the current research from behavioral genetics provides a great deal of evidence concluding that the home environment, as it is influenced by parents, accounts for 0 to 10% of the variance in the personality and intelligence outcomes of children. Heredity (genes) accounts for about 50% and the child’s peer group accounts for the remaining 40-50% of the variance (Pinker, 2002).
The major problem with the above referenced data has been the admitted narrowness with regard to the age and Social Economic Status (SES) of the participants. For the most part, the studies on twins and adopted children were conducted on middle class families with little relative diversity. On top of that, there is a dearth of research focusing on early childhood. This narrowness limits the generalization of findings across different populations and across age levels. Clearly, it is conceivable that parenting style will have varying levels of influence on child outcomes across the developmental lifespan. Over-generalization may lead to faulty thinking and thus very dangerous policy decisions.
Throughout my training and subsequent professional development, as a psychologist, I have been exposed to data suggesting that there is a fairly strong positive correlation between Social Economic Status (SES) and mental ability. The same is true with regard to academic achievement. The underlying message had always been that environmental determinates were responsible for these correlations. Again, the problem with this thinking is that the research upon which such beliefs were formed has largely lacked appropriate controls for heritability. Correlation is not causation and all that jazz!
So what happens to the data when children across the SES spectrum are assessed using techniques that control for genes? One particular study from 2003 suggested that “the heritability of cognitive ability in 7-year-old twins was only 10% in low-SES families but was 72% in high-SES families.” (Tucker-Drob, Rhemtulla, Harden, Turkmeimer & Fask, 2011) This suggests that the environment, including perhaps parenting style and experiential deprivation, play a much bigger role in hindering cognitive development in low SES children versus higher SES children. Further research has found similar, although not so striking, SES differences. Regardless, research within the field of behavioral genetics “suggests that the environment plays a substantial role in the expression of genetic variance in cognitive ability over the course of child development” (Tucker-Drob, et al., 2011). Regardless, questions persist about the degree of influence SES plays in mental ability outcomes and about what point in time the shared environment might affect development.
In a new study just published in Psychological Science by Tucker-Drob, et al. (2011) the authors looked at the mental ability of 750 twins (25% identical, 35% same sex fraternal, and 40% opposite sex fraternal), at 10- and 24-months of age. This sample closely represented US population statistics including a diverse cross section of children across the SES and racial spectrum. And the results were quite different.
At ten months of age, the authors report that the shared environment (the home) played the dominate role in the variance of mental ability scores in all households – rich or poor. There was very little apparent variation in mental ability attributable to heredity. At 24-months however, things get a little more complicated. For low SES children, the environment remains the key variable associated with differences in mental ability. Perhaps as much of 70% of the variance in mental ability is attributable to the shared home environment. While for high SES children, genes become the predominant variable associated with the differences in mental ability scores. Environment still plays a role but much less so. Smart parents have smart kids unhampered by environmental constraints.
Genes by SES
Looking at ability gains within individuals between the first assessment at ten months and the retest at 24 months, the high SES children made more gains than those from low SES homes. The difference was modest; however, a child in poverty is likely, simply as a function of SES, to score one standard deviation below a very well to do child on the mental ability test.
These findings suggest that for very young children, environment matters a great deal. This is particularly true for infants rich or poor; but it becomes much more important for poor toddlers. Poor kids are more vulnerable to the adversity associated with deprivation. Many factors have been examined in order to explain this discrepancy. The author of this current study wrote:
“…compared with higher-SES parents, lower-SES parents spend less time with their children (Guryan, Hurst, & Kearney, 2008), are less able to allocate time spent with children in accordance with their children’s developmental needs (Kalil, Ryan, & Corey, 2010), and are less sensitive in responding to their children’s signals (Bradley & Corwyn, 2002; De Wolff & Ijzendoorn, 1997).” (Tucker-Drob, et al., 2011).
One particularly illuminating study published by Hart and Risley in 1995 reported “that at age 3, children in professional families heard an average of 2153 words per hour, while children in working class families heard 1251 words per hour and children in welfare families heard only 616 words per hour. In professional families, parents not only talked more but also used more different words and provided a greater richness of nouns, modifiers and verbs. Parents spent a lot of time and effort asking their children questions, affirming and expanding their responses and encouraging their children to listen and notice how words relate and refer in order to prepare their children for a culture focusing on ‘‘symbols and analytic problem solving’’ (see Hart and Risley, 44 p 133). On the other hand, parents on welfare spent less time talking while they more frequently initiated topics and used more imperatives and prohibitions. These parents were more concerned with established customs such as obedience, politeness and conformity. Working-class families showed a mixture of the two cultures using imperatives and prohibitives while using rich language to label, relate and discuss objects.” (Duursma, Augustyn, & Zuckerman, 2008) The net effect is that poor children hear 30 million fewer words than do children of professionals by the time they reach their forth birthday.
The implications of these differences are profound. Replication of this research is necessary, but we also need greater clarification of the environmental attributes that culminate in the mental ability discrepancies. Should these SES differences stand up to the rigors of scientific scrutiny through replication it will be absolutely essential to invest further in early childhood programs. Jonah Lehrer (2011) likewise noted that: “Such statistics have led many researchers to highlight the importance of improving the early-childhood environments of poor children. Economists such as James Heckman, a Nobel laureate at the University of Chicago, have long advocated for increased investments in preschool education, but this latest study suggests that interventions need to begin even earlier. One possible model is the “Baby College” administered by the Harlem Children’s Zone, which seeks to equip brand-new parents with better parenting skills.”
These findings also reinforce the importance of programs such as Head Start and particularly Early Head Start. It is concerning that these very programs are often the most vulnerable to budget cuts in difficult times. I can’t help but wonder if we would prioritize early childhood development differently if the masses and our politicians were truly aware of these issues. Perhaps we should learn more about this and help spread the word to friends, family, and our representatives. Are we as a society really willing to passively submit to this self perpetuating cycle of poverty?
Duursma, E., Augusta, M., & Zuckerman, B. (2008). Reading Aloud to Children: The Evidence. Archives of Disease in Childhood. Vol 93 No 7.
Epstein, R. (2010). What Makes a Good Parent? Scientific American MIND. November/December 2010. (pgs 46-51).
Hart, B. & Risley, T. (1995). Meaningful differences in the everyday experience of young American children. Baltimore: Paul H. Brookes Publishing.
Lehrer, J. (2011). Why Rich Parents Don’t Matter. Wall Street Journal.com. 1/22/11
Pinker, S. (2002). The Blank Slate: The Modern Denial of Human Nature. New York: Penguin Books.
Tucker-Drob, E. M., Rhemtulla, M., Harden, K. P., Turkheimer, E., & Fask, D. (2011). Emergence of a Gene × Socioeconomic Status Interaction on Infant Mental Ability Between 10 Months and 2 Years. Psychological Science. 22(1) 125–133.
Have you ever heard someone make an argument that leaves you shaking your head in disbelief? Does it seem to you like some people are coming from a completely different reality than your own? If so, then this blog is for you. I have spent the last year trying to develop an understanding of the common thought patterns that drive the acrimonious spirit of our social and political dialogue. I am continually amazed by what I hear coming from seemingly informed people. I have assumed that some folks are either deluded, disingenuous, or downright ignorant. There is yet another possibility here, including the reality that different moral schema or belief systems may be driving their thinking. And if this is the case, how do these divergent processes come to be? I have learned a lot through this exploration and feel compelled do provide a recap of the posts I have made. I want to share with you those posts that have gathered the most traction and some that I believe warrant a bit more attention.
Over the past year I have posted 52 articles often dealing with Erroneous Thought Processes, Intuitive Thinking, and Rational Thought. Additionally, I have explored the down stream implications of these processes with regard to politics, morality, religion, parenting, memory, willpower, and general perception. I have attempted to be evidenced-based and objective in this process – striving to avoid the very trappings of confirmation bias and the erroneous processes that I am trying to understand. As it turns out, the brain is very complicated: and although it is the single most amazing system known to human kind, it can and does lead us astray in very surprising and alarming ways.
As for this blog, the top ten posts, based on the shear number of hits, are as follows:
- Attribution Error
- Nonmoral Nature, It is what it is.
- Multitasking: The Illusion of Efficacy
- Moral Instinct
- IAT: Questions of Reliability
- Are You a Hedgehog or a Fox?
- What Plato, Descartes, and Kant Got Wrong: Reason Does not Rule
- Illusion of Punditry
- Emotion vs.Reason: And the winner is?
What started out as ramblings from a curious guy in a remote corner of New York State ended up being read by folks from all over the planet. It has been a difficult process at times, consuming huge amounts of time, but it has also been exhilarating and deeply fulfilling.
I have been heavily influenced by several scientists and authors in this exploration. Of particular importance have been Steven Pinker, Daniel Simons, Christopher Chabris, Jonah Lehrer, Bruce Hood, Carl Sagan, and Malcolm Gladwell. Exploring the combined works of these men has been full of twists and turns that in some cases necessitated deep re-evaluation of long held beliefs. Holding myself to important standards – valuing evidence over ideology – has been an important and guiding theme.
Several important concepts have floated to the top as I poked through the diverse literature pertaining to thought processes. Of critical importance has been the realization that what we have, when it comes to our thought processes, is a highly developed yet deeply flawed system that has been shaped by natural selection over millions of years of evolution. Also important has been my increased understanding of the importance of genes, the basic element of selective pressures, as they play out in morality and political/religious beliefs. These issues are covered in the top ten posts listed above.
There are other worthy posts that did not garner as much attention as those listed above. Some of my other favorites included a review of Steven Pinker’s article in the New York Times (also titled Moral Instinct,) a look at Jonathon Haidt’s Moral Foundations Theory in Political Divide, as well as the tricks of Retail Mind Manipulation and the Illusion of Attention. This latter post and my series on Vaccines and Autism (Part 1, Part 2, Part 3) were perhaps the most important of the lot. Having the content of these become general knowledge would make the world a safer place.
The evolution of understanding regarding the power and importance of Intuitive relative to Rational Thinking was humbling at times and Daniel Simons’ and Christopher Chabris’ book, The Invisible Gorilla, certainly provided a mind opening experience. Hey, our intuitive capabilities are incredible (as illustrated by Gladwell in Blink & Lehrer in How We Decide) but the downfalls are amazingly humbling. I’ve covered other topics such as happiness, superstition, placebos, and the debate over human nature.
The human brain, no matter how remarkable, is flawed in two fundamental ways. First, the proclivities toward patternicity (pareidolia), hyperactive agency detection, and superstition, although once adaptive mechanisms, now lead to many errors of thought. Since the age of enlightenment, when human kind developed the scientific method, we have exponentially expanded our knowledge base regarding the workings of the world and the universe. These leaps of knowledge have rendered those error prone proclivities unessential for survival. Regardless, they have remained a dominant cognitive force. Although our intuition and rapid cognitions have sustained us, and in some ways still do, the everyday illusions impede us in important ways.
Secondly, we are prone to a multitude of cognitive biases that diminish and narrow our capacity to truly understand the world. Time after time I have written of the dangers of ideology with regard to its capacity to put blind-folds on adherents. Often the blind- folds are absolutely essential to sustain the ideology. And this is dangerous when truths and facts are denied or innocents are subjugated or brutalized. As I discussed in Spinoza’s Conjecture: “We all look at the world through our personal lenses of experience. Our experiences shape our understanding of the world, and ultimately our understanding of [it], then filters what we take in. The end result is that we may reject or ignore new and important information simply because it does not conform to our previously held beliefs.
Because of our genetically inscribed tendencies toward mysticism and gullibility, we must make extra effort in order to find truth. As Dr. Steven Novella once wrote:
“We must realize that the default mode of human psychology is to grab onto comforting beliefs for purely emotional reasons, and then justify those beliefs to ourselves with post-hoc rationalizations. It takes effort to rise above this tendency, to step back from our beliefs and our emotional connection to conclusions and focus on the process.”
We must therefore be humble with regard to beliefs and be willing to accept that we are vulnerable to error prone influences outside our awareness. Recognition and acceptance of these proclivities are important first steps. Are you ready to move forward? How do you think?
Posted by Gerald Guild
Categories: Adaptive Unconscious
, Erroneous Thinking
, Invisible Gorilla
, Placebo Effect
, Rational Thought
| Tagged: Attribution Error
, Cognitive Biases
, Confirmation Bias
, Erroneous Thinking
, Intuitive Thinking
, Invisible Gorilla
, Rational Thought
, Self Serving Bias
, Spinoza's Conjecture
As I read Steven Pinker’s book The Blank Slate: Modern Denial of Human Nature I was, for lack of a better word, flabbergasted, about the extent of acrimony that seemingly persists regarding the nature versus nurture debate. This parley, from my naive perspective, was over long ago. Yet Pinker detailed the extensive history to which some intellectuals, even today, attack the notion of any genetic contribution to traits such as IQ, behavior, political views, religious views, and personality.
For me there is very little question about the impact of genes. It is clear as day in my family. My daughter for example is very much like me. And I see the influence of genes nearly every day in my practice. As a psychologist with a specialty in evaluating and treating difficult to manage children (i.e., Autism Spectrum Disorder, Oppositional Defiant Disorder, and ADHD), I often work with families who have an exceptionally strong willed and self directed child. The children that have these latter traits, without Autistic like symptoms, are often classified as Oppositional Defiant. Along with such independent mindedness, typically comes an explosive temperament and a highly sensitive and precocious level of personal dignity. It is important to note that a vast majority of the time, the child is a proverbial chip off the ole-block: usually, the father was similarly quite difficult to manage as a youngster.
One with a nurture bias might suggest that my daughter and those oppositional children I see are simply products of their environment. But here is what is interesting. Often in the families I serve, there are other well behaved, well adjusted, and polite children. To suggest that the environment uniquely and exclusively shaped the behavior and affect of the troubled child would suggest that there was a substantial level of differential parenting going on in the home. This scenario is far too common to be a product of differentiated parenting style. And thorough behavioral analysis almost always rules out this variable. Socially, the parents are blamed for their bad kid, not because of their gene contribution, but because their alleged poor parenting practices. Well, most often, poor parenting is not the cause of the problem! And my daughter’s similarity to me unfolded despite my attempts to foster in her, her own unique identity and insufficient environmental influence.
The argument really is moot. Genes do matter! The evidence is substantial and it transcends the anecdotes I just shared. Only those with an ideological position inconvenienced by this reality argue otherwise. I actually prefer the idea that genes don’t matter. It would give me greater capacity to affect change in homes given my behavior analytic skills. It would also give me more hope that my daughter will not develop the same geeky interests that I have. Too late! She is a geology major. Like me, she loves rocks. It would also give me hope that she wont develop the same G/I ailments that have incapacitated me, my mother, and my grandfather. Again too late. Sadly, the other day she had to buy some Tums.
People are uncomfortable with the idea that issues such as personality and IQ, for example, would have any genetic determinism. It seems too limiting, too materialistic, and too deterministic. People, I think, are more comfortable with the idea that they can affect change – that they can arrange outcomes, that the power is in our hands. But the real power, it seems, is spread out – residing both in our hands and in our genes. Environmental determinism, in fact, is more consistent with my political and social views, but no matter how inconvenient, I am compelled by evidence to soften my stance regarding this romantic notion. How I wish that DNA did not enter the picture with regard to such issues. Or do I? Had it not, we wouldn’t be here to write/read such musings. You’ve heard of the whole evolution by means of natural selection thing, haven’t you?
As it turns out, we are products of our genes and our environment. No duh! Debate over! Right? Nope! I had assumed that it was commonly accepted that genes matter. I had no idea that acknowledging this reality was in a sense sacrilegious to some. Although Pinker made clear the debate, I suspected that perhaps this was an esoteric intellectual war of words limited to philosophical types with high brow notions about macro economic models and so on. But, I became more aware of the lingering embers of environmental determinism as a result of a firestorm that erupted last week regarding an essay written by an environmental advocacy group spread about on Twitter and a subsequent article posted in the Huffington Post. These articles essentially minimized genetic determinism in major health issues due to the failure of the Human Genome Project to isolate specific genes responsible for specific illnesses. Out with the genes – in with the environment the proponents celebrated. Environmental determinists pounced on the absence of evidence as if it were evidence of absence (Carmichael, 2010). As it turns out, genes are really complex and diseases are influenced, it seems, by gene cohorts rather than any one specific gene. I am less familiar with the research regarding genetic influence on disease but the tone of the banter reminded me of the debate about human nature detailed by Pinker.
I have discussed in several recent posts the impact of genes on important issues such as personality, adaptive functioning, and even political perspectives. The psychologist Eric Turkheimer pulled together the unusually robust evidence from extensive studies of twins (fraternal and identical) reared together and apart as well as studies of adopted children relative to biological children and concluded that there are three important laws that help explain the development of personality characteristics and intelligence. The three laws are as follows:
- All Human traits are heritable;
- The effect of being raised in the same family is smaller than the effect of the genes; and
- A substantial portion of the variation in complex human behavioral traits is not accounted for by the effects of genes or families.
These laws are best summarized based on current research from behavioral genetics as follows:
- Heredity accounts for about 50% of the variance in the adaptive functioning outcomes of children.
- The home environment, as it is influenced by parents, accounts for 0 to 10%, and
- The child’s peer group accounts for the remainder (40-50%) (Pinker, 2002).
Corresponding laws regarding the variants affecting diseases are perhaps unclear at this time. But denial of genetic influence is much like the denial of the heliocentric theory of the solar system or the arguments put forth by Creationists and anti vaccine advocates. They are guided by ideological notions that hang by a thin thread. Something near and dear to the hearts of the proponents of exclusive environmental determinism is threatened by evidence. The only recourse is denial. Its an old and tired song and dance. Genes matter – but not exclusively. Environment matters – but not exclusively. Get used to it.
Carmichael, M. (2010). DNA, Denial, and the Rise of “Environmental Determinism”. Wild Type. http://marycarmichael.wordpress.com/2010/12/22/dna-denial-and-the-rise-of-environmental-determinism/#comments
Katz, D. (2010). Is There a Genie in the Genome? The Huffington Post. http://www.huffingtonpost.com/david-katz-md/is-there-a-genie-in-the-g_b_792844.html
Latham, J., & Wilson, A. (2010). The Great DNA Data Deficit: Are Genes for Disease a Mirage? The Bioscience Resource Project Commentaries. http://www.bioscienceresource.org/commentaries/article.php?id=46
Pinker, S. (2002). The Blank Slate: Modern Denial of Human Nature. New York: Penguin Books.