Labrador retriever running an obstacle course. Can dog intelligence shed light on human intelligence? (source)
My last post described a Chinese project to identify the many genes that contribute to normal variation in human intelligence. If successful, it will simply demonstrate what we already know, i.e., genes are largely responsible for the differences in intelligence we see among normal individuals.
We know this from intelligence testing, particularly from studies on IQ differences between twins. This evidence, however, has been largely discredited in the eyes of many people, particularly those who act as gatekeepers in the halls of academia. As one scholar told me:
A key problem is funding. Intellectuals on today’s review panels 'came to consciousness' in a climate when intelligence testing was thought to be wrong and invalid. Very few scientists are open to new ideas […] So it often takes a generational turn-over before there is a swing back to a fresh look at intelligence.
I doubt things will change much when the old guard dies off. In some ways, the academic environment was more open-minded two decades ago, when there were still people, often in key positions, who had entered academia before the 1960s. Change will probably come when new evidence manages to bypass the gatekeepers, and this will most likely happen where the marketplace of ideas is less controlled, like in China. Yes, the same country we like to scold for not being sufficiently free and democratic.
What other new evidence could bring change? This question led me to ask the h-bd discussion list: “If you had access to sufficient funding, equipment, and trained personnel, what kind of research project would you like to do or see done?”
A behavioral geneticist suggested the following projects:
1) Investigate individual differences in cognitive abilities in other animal models. a) create a reliable scale. b) establish whether a g factor emerges in other mammals. c) find out the correlates of such a g factor (phenotypic and genetic)- which would be uncontaminated by SES and therefore lay to rest many controversies that arise in humans studies. [Disclaimer, I have started on this with dogs (60 dogs, all one breed, all farm living and am actively seeking funding to continue the project].
2) Investigate the correlates (particularly fitness-relevant correlates of intelligence in populations of hunter-gatherers. Not to examine mean differences between populations - but to test evolutionary hypotheses. Is intelligence associated with offspring number? Social status? Health? Life expectancy? We do not know the fitness optima for intelligence in any human population.
As for myself, I would want to determine whether the Visual Word Form Area is a product of nature or nurture. This could be done by following the same methodology that Zhu et al. (2009) used to prove that our ability to recognize faces is largely hardwired. If the same is true, or even partly true, for our ability to recognize strings of letters, i.e., words, we would have a compelling argument for gene-culture co-evolution.
I would also want to see whether Tay-Sachs carriers, i.e., heterozygotes, really do have a higher mean intelligence than people without this allele (Frost, 2011). Such a study would be a cinch to do, yet no one has bothered. How come?
Finally, as with hbd* chick, my eyes glaze over when discussion focuses too long on IQ or SAT scores. We need to go beyond intelligence and look at genetic differences that may underlie variation in personality traits, regulation of emotions, time orientation, and so forth. There is more to being human than just intelligence.
References
Frost, P. (2011) Five years later … still no study, February 4, Evo and Proud.
http://evoandproud.blogspot.ca/2011/02/five-years-later-still-no-study.htmlZhu, Q., Y. Song, S. Hu, X. Li, M. Tian, Z. Zhen, Q. Dong, N. Kanwisher, and J. Liu. (2009). Heritability of the specific cognitive ability of face perception, Current Biology, 20, 137-142.