by danielford on 7/17/12, 1:53 PM with 163 comments
by justin_vanw on 7/17/12, 6:25 PM
There is a strong cultural bias among much of the research community to go out of their way to deny any genetic factors in intelligence. Perhaps this is well intentioned, but it is absurd.
I have come across very few squirrels that have mastered fire, or could be taught calculus, or even addition. I doubt that this is cultural or due to the squirrels upbringing, diet, social status, or how many books the squirrel has available to it, or the quality of it's teachers, or pathogens. Clearly then, it is possible for genetics to completely dominate other factors in determining intelligence. In the animal kingdom at large heredity/genetics account for basically all of the variation in intelligence.
The unanswered question is whether there is enough genetic diversity across the human species to cause intelligence to be significantly hereditable. The fear among scientists that try to keep the lid on this question is that the answer might be yes, and worse that such variations will correlate with geographic or national groupings. This would put a very nasty perceived scientific stamp of approval on racism (even though this would be unjustified), and could over time lead to discrimination and 'scientific racism'.
Anyway, in the end science will uncover the truth here, and in the meantime it is probably very prudent to not make any potentially inflammatory statements and to be very cautious about any studies that could fuel hate. I just find it absurd that whenever this kind of question comes up people start denying that there is any hereditary component of intelligence, and that IQ is completely meaningless, etc.
by kenjackson on 7/17/12, 3:22 PM
As noted by the author, this suggests that IQ only captures a portion of early childhood intervention benefits. And goes counter to those who suggest that early intervention programs serve no purpose if IQ doesn't remain high (IOW, IQ is only a portion of what constitutes success in life).
by Dn_Ab on 7/17/12, 4:29 PM
Basically he suggests thinking about the formation of intelligence to be something like trying to run an obstacle course while holding an armful of things and trying to drop as little as possible. Essentially, he is arguing that there is some optimal or standard brain and since any mutation introduced into the brain is more likely to be harmful than beneficial, more intelligent individuals are not those that inherited some specific genes for intelligence but are most likely those who avoided the most damaging non-specific mutations.
That’s [runaway selection of intelligence boosting genes] all nice, though admittedly speculative, but those mutations are the ones that we would expect to not vary in human populations – they would now be fixed. In particular, there is little reason to expect that there would exist new mutations in such genes, present in some but not all humans, which act to further increase intelligence.
To test this he suggests using symmetry as a proxy for robustness in the individual. This fits well with the fact that all attempts thus far to find a common genetic basis for intelligence have failed, the correlation between intelligence and immune function, ideas that intelligence was indirectly selected when optimizing for healthy mates and findings that Nootropic like substances tend to have the least effect on already intelligent minds. In the last case, it is interesting to note nootropics should then be viewed not cheating but more leveling of the playing field. Taking this further, genetics are not the only obstacle course - there is still variation in the womb environment and early childhood. The interplay of genes and the stability of process in the growing brain; affected by a lack of stimulation, poor nutrition and a stressful womb environ would likely have more impactful effects on intelligence than pure genetics.
by vibrunazo on 7/17/12, 8:40 PM
New findings about the impact of genetic vs environmental influences on IQ tests. Is about as useful finding new evidence about genetic vs environmental influences on people's ability to pass a "lick your elbow" test. Why should I care? It sure is interesting, and hey, anything "for science!". But, meh...
by Symmetry on 7/17/12, 2:55 PM
It's always seemed obvious to me that this ought to be true - that is that environment will matter more if you have greater differences in environment. In the extreme case if you feed kid A and don't feed kid B, then kid A will end up with an infinitely greater IQ than kid B.
by OmegaHN on 7/17/12, 4:37 PM
If the writer is talking about IQ, then these investigations aren't interesting, as IQ is a very small subset of intelligence (the ability to solve those types of problems on a test, which you can easily train for). If the writer is talking about general intelligence, then the writer really shouldn't be mentioning IQ at all, as it is notorious for being confused as actual intelligence.
by character on 7/17/12, 4:48 PM
by Xcelerate on 7/17/12, 3:29 PM
I would think that much like how different types of people from different regions have differing athletic capabilities, there would also be differences in mental facilities as well -- some better at music, some better at math, etc. Thoughts?
by tokenadult on 7/17/12, 3:16 PM
Nisbett, R. E., Aronson, J., Blair, C., Dickens, W., Flynn, J., Halpern, D. F., & Turkheimer, E. (2012, January 2). Intelligence: New Findings and Theoretical Developments. American Psychologist, 67, 130-159.
http://psychology.msu.edu/pers_hambric3/PSY493%20Spring%2020...
Daniel Willingham reviews in the submitted post, and the paper is a joint review article on the last decade and a half of research on human intelligence by an all-star group of researchers.
After edit: I see other comments are asking about what the research shows about genetic influences on IQ and environmental influences on IQ. Here is some FAQ information on that, originally part of another comment I posed here on HN:
The researchers in the Behavior Genetics Association are making increasingly cautious statements about genetic influence on human behavioral traits as more data are amassed. Here are some of the latest statements by some of the leading researchers.
Turkheimer, E. (2012). Genome wide association studies of behavior are social science. In K. S. Plaisance & T.A.C. Reydon (Eds.) Philosophy of Behavioral Biology (pp. 43-64). New York, NY: Springer.
http://people.virginia.edu/~ent3c/papers2/Turkheimer%20GWAS%...
"If the history of empirical psychology has taught researchers anything, it is that correlations between causally distant variables cannot be counted on to lead to coherent etiological models."
Johnson, W., Turkheimer, E., Gottesman, I. I., & Bouchard, T. J. (2009). Beyond heritability: Twin studies in behavioral research. Current Directions in Psychological Science, 18, 217-220. [I am personally acquainted with three of the four co-authors of this paper, one of whom regularly exchanges links with me by email.]
http://people.virginia.edu/~ent3c/papers2/Articles%20for%20O...
"Moreover, even highly heritable traits can be strongly manipulated by the environment, so heritability has little if anything to do with controllability. For example, height is on the order of 90% heritable, yet North and South Koreans, who come from the same genetic background, presently differ in average height by a full 6 inches (Pak, 2004; Schwekendiek, 2008)."
Turkheimer, E. (2008, Spring). A better way to use twins for developmental research. LIFE Newsletter, 2, 1-5.
http://people.virginia.edu/~ent3c/papers2/Articles%20for%20O...
"Unfortunately, that fundamental intuition is wrong. Heritability isn’t an index of how genetic a trait is. A great deal of time has been wasted in the effort of measuring the heritability of traits in the false expectation that somehow the genetic nature of psychological phenomena would be revealed. There are many reasons for making this strong statement, but the most important of them harkens back to the description of heritability as an effect size."
by brittohalloran on 7/17/12, 4:55 PM
"In particular, there is clear evidence that school affects intelligence."
by ramses on 7/18/12, 2:44 AM
I would like to mention that Jaeggi's results, and working memory training in general, have not been replicated.
The main issue with Jaeggi's experiment, is that proper controls were not used.
For a careful examination, and I would say thorough debunking of Jaeggi's results on dual n-back and g(F) improvement by training working memory, please read:
No Evidence of Intelligence Improvement After Working Memory Training: A Randomized, Placebo-Controlled Study. Redick, Thomas S.; Shipstead, Zach; Harrison, Tyler L.; Hicks, Kenny L.; Fried, David E.; Hambrick, David Z.; Kane, Michael J.; Engle, Randall W. Journal of Experimental Psychology: General, Jun 18 , 2012, No Pagination Specified. doi: 10.1037/a0029082
by rikelmens on 7/17/12, 5:42 PM
http://www.diseaseproof.com/archives/healthy-pregnancy-does-...
Additionally, checkout the: http://www.omega3.org/
by zmoney on 7/17/12, 5:47 PM
Statements like “when babies from poor families are adopted into wealthy families, their IQ goes up” are almost devoid of information because the IQ test itself favors the type of “intelligence” valued by the educated, wealthy class.
by Cyndre on 7/17/12, 10:08 PM
by light3 on 7/18/12, 8:52 AM
by ekianjo on 7/18/12, 2:06 AM
by EREFUNDO on 7/17/12, 9:15 PM
by Xcelerate on 7/17/12, 6:19 PM
by rokhayakebe on 7/17/12, 6:39 PM