"Embryo Selection for Cognitive Enhancement: Curiosity or Game-changer?", Shulman & Bostrom 2013:
...advances in genomics will make it possible to enhance human intellectual abilities. One way to do this would be via embryo selection in the context of in vitro fertilization (IVF). In this article, we analyze the feasibility, timescale, and possible societal impacts of embryo selection for cognitive enhancement. We find that embryo selection, on its own, may have significant impacts, but likely not drastic ones, over the next 50 years, though large effects could accumulate over multiple generations. However, there is a complementary technology, stem cellderived gametes, which has been making rapid progress and which could amplify the impact of embryo selection, enabling very large changes if successfully applied to humans.
...recent work using genomewide complex trait analysis (GCTA) suggests that most of the "missing heritability" for cognitive ability can be attributed to a large number of common variants with individually tiny effect sizes (Davies et al, 2011; Benyamin et al, 2013; Plomin et al., 2013). Such variants can be detected with existing methods, but doing so requires extremely large sample sizes to clearly distinguish such weak effects from random noise.
Much larger sample sizes are practical. In the short term, the United Kingdom Biobank project has collected survey data and biological samples from some 500,000 individuals, and has hired a firm to perform genetic testing in 2014. The samples are tagged with educational and income data, and a third include a cognitive ability test. The rapidly growing consumer genomics firm 23andme (2013) already has over 350,000 customers, 90% of whom have opted in to participate in research. In the longer term, as DNA testing becomes a routine part of medical care, datasets of tens of millions of individuals may be assembled from data produced for medical reasons. Such databases could be matched against standardized test scores, educational data, and income to produce extraordinary sample sizes at low marginal cost. Thus, while our understanding of the genetic correlates of cognitive ability is very limited today, it is set to increase dramatically in the coming years.
Studies in labor economics typically find that 1 IQ point corresponds to an increase in wages on the order of 1%, other things equal, though higher estimates are obtained when effects of IQ on educational attainment are included (Zax and Rees, 2002; Neal and Johnson, 1996; Cawley et al., 1997; Behrman et al., 2004; Bowles et al., 2002; Grosse et al. 2002).
- Zax, J. S., and Rees, D. I (2002) 'IQ, academic performance, environment, and earnings', Review of Economics and Statistics, 84(4), pp. 600616. DOI:10.1162/003465302760556440.
- Neal: missing TODO emailed Bostrom
- Cawley, J., Conneely, K., Heckman, J., and Vytlacil, E. (1997) 'Cognitive Ability, Wages, and Meritocracy', in B. Devlin, S. E. Fienber, D, P. Resnick and K. Roeder (eds.), Intelligence, Genes, and Success: Scientists Respond to The Bell Curve. New York: SpringerVerlag
- Behrman, J., Alderman, H., and Hoddinott, J. (2004) 'Copenhagen Consensus-Challenges and Opportunities: Hunger and Malnutrition', Global Crises, Global Solutions [online]. Available from: http://greencardeb5expert.com/PDF/Hunger_and_Malnutrition.pdf [Accessed 11 August 2013].
- Bowles, S., Gintis, H., and Osborne, M. (2002) 'The determinants of individual earnings: Skills, preferences, and schooling', Journal of Economic Literature, 39(4), pp. 11371176.
- Grosse, D. S., et al. (2002) 'Economic Gains Resulting from the Reduction in Children's Exposure to Lead in the United States' Environmental Health Perspectives, 110 (6), pp. 563569. DOI:10.1289/ehp.02110563
The standard deviation of IQ in the population is about 15. Davies et al. (2011) estimates that common additive variation can account for half of variance in adult fluid intelligence in its sample. Siblings share half their genetic material on average. Thus, in a crude estimate, variance is cut by 75% and standard deviation by 50%. Adjustments for assortative mating, deviation from the Gaussian distribution, and other factors would adjust this estimate, but not drastically. These figures were generated by simulating 10 million couples producing the listed number of embryos and selecting the one with the highest predicted IQ based on the additive variation.
...
Table 1: How the maximum amount of IQ gain (assuming a Gaussian distribution of predicted IQs among the embryos with a standard deviation of 7.5 points1) might depend on the number of embryos used in selection:
Selection | IQ points gained
1 in 2: 4.2
1 in 10: 11.5
1 in 100: 18.8
1 in 1000: 24.3
5 generations of 1in10: < 65 [b/c diminishing returns]
10 generations of 1in10: < 130 [b/c diminishing returns]
Cumulative limits (additive variants optimized for cognition): 100+ (<300 [b/c diminishing returns])
...Standard practice today involves the creation of fewer than 10 embryos. Selection among greater numbers than that would require multiple IVF cycles, which is expensive and burdensome. 1in10 selection may thus represent an upper limit of what would currently be practically feasible. New techniques for maturing eggs in vitro might make the creation of more embryos feasible, though with diminishing returns. If some selection power were expended on traits other than intelligence (e.g. health, longevity, or appearance), the selection left for cognitive traits would be further reduced.
Interestingly, part of the increase in the number of people above high ability thresholds will "lag by one generation". This is due to a statistical property of truncation selection on a Gaussian distribution. If one selects 1 out of n embryos, the number of individuals meeting some high threshold must increase by less than nfold in the first generation. In the next generation, the portion meeting high thresholds could increase by orders of magnitude, depending on the threshold.
The effectiveness of embryo selection would be vastly increased if multiple generations of selection could be compressed into less than a human maturation period. This could be enabled by advances in an important complementary technology: the derivation of viable sperm and eggs from human embryonic stem cells. Such stemcell derived gametes would enable what we will term "iterated embryo selection" (henceforth, IES):
1. Genotype and select a number of embryos that are higher in desired genetic characteristics.
2. Extract stem cells from those embryos and convert them to sperm and ova, maturing within 6 months or less (Sparrow, 2013).
3. Cross the new sperm and ova to produce embryos.
4. Repeat until large genetic changes have been accumulated.
IES has recently drawn attention from bioethics (Sparrow, 2013; see also Miller, 2012; Machine Intelligence Research Institute, 2009) in light of rapid scientific progress. Since the Hinxton Group (2008) predicted that human stem cellderived gametes would be available within 10 years, the techniques have been used to produce fertile offspring in mice, and gametelike cells in humans. However, substantial scientific challenges remain in translating animal results to humans, and in avoiding epigenetic abnormalities in the stem cell lines. These challenges might delay human application "10 or even 50 years in the future" (Cyranoski, 2013).
To avoid negative effects of inbreeding, IES would require either a large starting supply of donors, or the expenditure of substantial selective power to reduce harmful recessive alleles. These factors would tend to push towards IES offspring being less genetically related to their parents (though more related to one another), and could affect the appeal of IES. The history of sperm donation suggests this may be a serious barrier. However, there is some demand for the opportunity to raise genetically unrelated children. In 2008, 136,000 children were adopted in the United States (Child Welfare Information Gateway, 2011), while 4,247,694 children were born (Martin et al., 2010). IES embryos might inspire much greater demand because of their exceptional qualities, though adoptive parents motivated by a desire to save children from poor circumstances may be less attracted to IES.
Birth rates and maturation times moderate the impacts in the short and medium term. If workers join the labor force at age 20 and remain there for an average of 40 years, then the growth of the enhanced share of the workforce would be spread over at least 60 years. This suggests practical effects would be concentrated in the second half of the century, although policies affecting the technology and its use would determine the number of children growing up decades earlier. While these lags are long, they are comparable to timescales for other interventions that receive political attention, such as effort to improve lifetime outcomes through prenatal care, preschool, and childhood nutrition
...advances in genomics will make it possible to enhance human intellectual abilities. One way to do this would be via embryo selection in the context of in vitro fertilization (IVF). In this article, we analyze the feasibility, timescale, and possible societal impacts of embryo selection for cognitive enhancement. We find that embryo selection, on its own, may have significant impacts, but likely not drastic ones, over the next 50 years, though large effects could accumulate over multiple generations. However, there is a complementary technology, stem cellderived gametes, which has been making rapid progress and which could amplify the impact of embryo selection, enabling very large changes if successfully applied to humans.
...recent work using genomewide complex trait analysis (GCTA) suggests that most of the "missing heritability" for cognitive ability can be attributed to a large number of common variants with individually tiny effect sizes (Davies et al, 2011; Benyamin et al, 2013; Plomin et al., 2013). Such variants can be detected with existing methods, but doing so requires extremely large sample sizes to clearly distinguish such weak effects from random noise.
Much larger sample sizes are practical. In the short term, the United Kingdom Biobank project has collected survey data and biological samples from some 500,000 individuals, and has hired a firm to perform genetic testing in 2014. The samples are tagged with educational and income data, and a third include a cognitive ability test. The rapidly growing consumer genomics firm 23andme (2013) already has over 350,000 customers, 90% of whom have opted in to participate in research. In the longer term, as DNA testing becomes a routine part of medical care, datasets of tens of millions of individuals may be assembled from data produced for medical reasons. Such databases could be matched against standardized test scores, educational data, and income to produce extraordinary sample sizes at low marginal cost. Thus, while our understanding of the genetic correlates of cognitive ability is very limited today, it is set to increase dramatically in the coming years.
Studies in labor economics typically find that 1 IQ point corresponds to an increase in wages on the order of 1%, other things equal, though higher estimates are obtained when effects of IQ on educational attainment are included (Zax and Rees, 2002; Neal and Johnson, 1996; Cawley et al., 1997; Behrman et al., 2004; Bowles et al., 2002; Grosse et al. 2002).
- Zax, J. S., and Rees, D. I (2002) 'IQ, academic performance, environment, and earnings', Review of Economics and Statistics, 84(4), pp. 600616. DOI:10.1162/003465302760556440.
- Neal: missing TODO emailed Bostrom
- Cawley, J., Conneely, K., Heckman, J., and Vytlacil, E. (1997) 'Cognitive Ability, Wages, and Meritocracy', in B. Devlin, S. E. Fienber, D, P. Resnick and K. Roeder (eds.), Intelligence, Genes, and Success: Scientists Respond to The Bell Curve. New York: SpringerVerlag
- Behrman, J., Alderman, H., and Hoddinott, J. (2004) 'Copenhagen Consensus-Challenges and Opportunities: Hunger and Malnutrition', Global Crises, Global Solutions [online]. Available from: http://greencardeb5expert.com/PDF/Hunger_and_Malnutrition.pdf [Accessed 11 August 2013].
- Bowles, S., Gintis, H., and Osborne, M. (2002) 'The determinants of individual earnings: Skills, preferences, and schooling', Journal of Economic Literature, 39(4), pp. 11371176.
- Grosse, D. S., et al. (2002) 'Economic Gains Resulting from the Reduction in Children's Exposure to Lead in the United States' Environmental Health Perspectives, 110 (6), pp. 563569. DOI:10.1289/ehp.02110563
The standard deviation of IQ in the population is about 15. Davies et al. (2011) estimates that common additive variation can account for half of variance in adult fluid intelligence in its sample. Siblings share half their genetic material on average. Thus, in a crude estimate, variance is cut by 75% and standard deviation by 50%. Adjustments for assortative mating, deviation from the Gaussian distribution, and other factors would adjust this estimate, but not drastically. These figures were generated by simulating 10 million couples producing the listed number of embryos and selecting the one with the highest predicted IQ based on the additive variation.
...
Table 1: How the maximum amount of IQ gain (assuming a Gaussian distribution of predicted IQs among the embryos with a standard deviation of 7.5 points1) might depend on the number of embryos used in selection:
Selection | IQ points gained
1 in 2: 4.2
1 in 10: 11.5
1 in 100: 18.8
1 in 1000: 24.3
5 generations of 1in10: < 65 [b/c diminishing returns]
10 generations of 1in10: < 130 [b/c diminishing returns]
Cumulative limits (additive variants optimized for cognition): 100+ (<300 [b/c diminishing returns])
...Standard practice today involves the creation of fewer than 10 embryos. Selection among greater numbers than that would require multiple IVF cycles, which is expensive and burdensome. 1in10 selection may thus represent an upper limit of what would currently be practically feasible. New techniques for maturing eggs in vitro might make the creation of more embryos feasible, though with diminishing returns. If some selection power were expended on traits other than intelligence (e.g. health, longevity, or appearance), the selection left for cognitive traits would be further reduced.
Interestingly, part of the increase in the number of people above high ability thresholds will "lag by one generation". This is due to a statistical property of truncation selection on a Gaussian distribution. If one selects 1 out of n embryos, the number of individuals meeting some high threshold must increase by less than nfold in the first generation. In the next generation, the portion meeting high thresholds could increase by orders of magnitude, depending on the threshold.
The effectiveness of embryo selection would be vastly increased if multiple generations of selection could be compressed into less than a human maturation period. This could be enabled by advances in an important complementary technology: the derivation of viable sperm and eggs from human embryonic stem cells. Such stemcell derived gametes would enable what we will term "iterated embryo selection" (henceforth, IES):
1. Genotype and select a number of embryos that are higher in desired genetic characteristics.
2. Extract stem cells from those embryos and convert them to sperm and ova, maturing within 6 months or less (Sparrow, 2013).
3. Cross the new sperm and ova to produce embryos.
4. Repeat until large genetic changes have been accumulated.
IES has recently drawn attention from bioethics (Sparrow, 2013; see also Miller, 2012; Machine Intelligence Research Institute, 2009) in light of rapid scientific progress. Since the Hinxton Group (2008) predicted that human stem cellderived gametes would be available within 10 years, the techniques have been used to produce fertile offspring in mice, and gametelike cells in humans. However, substantial scientific challenges remain in translating animal results to humans, and in avoiding epigenetic abnormalities in the stem cell lines. These challenges might delay human application "10 or even 50 years in the future" (Cyranoski, 2013).
To avoid negative effects of inbreeding, IES would require either a large starting supply of donors, or the expenditure of substantial selective power to reduce harmful recessive alleles. These factors would tend to push towards IES offspring being less genetically related to their parents (though more related to one another), and could affect the appeal of IES. The history of sperm donation suggests this may be a serious barrier. However, there is some demand for the opportunity to raise genetically unrelated children. In 2008, 136,000 children were adopted in the United States (Child Welfare Information Gateway, 2011), while 4,247,694 children were born (Martin et al., 2010). IES embryos might inspire much greater demand because of their exceptional qualities, though adoptive parents motivated by a desire to save children from poor circumstances may be less attracted to IES.
Birth rates and maturation times moderate the impacts in the short and medium term. If workers join the labor force at age 20 and remain there for an average of 40 years, then the growth of the enhanced share of the workforce would be spread over at least 60 years. This suggests practical effects would be concentrated in the second half of the century, although policies affecting the technology and its use would determine the number of children growing up decades earlier. While these lags are long, they are comparable to timescales for other interventions that receive political attention, such as effort to improve lifetime outcomes through prenatal care, preschool, and childhood nutrition