Superintelligence: Paths, Dangers, Strategies (9 page)

Biomedical enhancements could give bigger boosts. Drugs already exist that are alleged to improve memory, concentration, and mental energy in at least some subjects.
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(Work on this book was fueled by coffee and nicotine chewing gum.) While the efficacy of the present generation of smart drugs is variable, marginal, and generally dubious, future nootropics might offer clearer benefits and fewer side effects.
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However, it seems implausible, on both neurological and evolutionary grounds, that one could by introducing some chemical into the brain of a healthy person spark a dramatic rise in intelligence.
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The cognitive functioning
of a human brain depends on a delicate orchestration of many factors, especially during the critical stages of embryo development—and it is much more likely that this self-organizing structure, to be enhanced, needs to be carefully balanced, tuned, and cultivated rather than simply flooded with some extraneous potion.

Manipulation of genetics will provide a more powerful set of tools than psychopharmacology. Consider again the idea of genetic selection: instead of trying to implement a eugenics program by controlling mating patterns, one could use selection at the level of embryos or gametes.
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Pre-implantation genetic diagnosis has already been used during in vitro fertilization procedures to screen embryos produced for monogenic disorders such as Huntington’s disease and for predisposition to some late-onset diseases such as breast cancer. It has also been used for sex selection and for matching human leukocyte antigen type with that of a sick sibling, who can then benefit from a cord-blood stem cell donation when the new baby is born.
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The range of traits that can be selected for or against will expand greatly over the next decade or two. A strong driver of progress in behavioral genetics is the rapidly falling cost of genotyping and gene sequencing. Genome-wide complex trait analysis, using studies with vast numbers of subjects, is just now starting to become feasible and will greatly increase our knowledge of the genetic architectures of human cognitive and behavioral traits.
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Any trait with a non-negligible heritability—including cognitive capacity—could then become susceptible to selection.
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Embryo selection does not require a deep understanding of the causal pathways by which genes, in complicated interplay with environments, produce phenotypes: it requires only (lots of) data on the genetic correlates of the traits of interest.

It is possible to calculate some rough estimates of the magnitude of the gains obtainable in different selection scenarios.
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Table 5
shows expected increases in intelligence resulting from various amounts of selection, assuming complete information about the common additive genetic variants underlying the narrow-sense heritability of intelligence. (With partial information, the effectiveness of selection would be reduced, though not quite to the extent one might naively
expect.
⁴⁴
) Unsurprisingly, selecting between larger numbers of embryos produces larger gains, but there are steeply diminishing returns: selection between 100 embryos does not produce a gain anywhere near fifty times as large as that which one would get from selection between 2 embryos.
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Table 5
Maximum IQ gains from selecting among a set of embryos
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Interestingly, the diminishment of returns is greatly abated when the selection is spread over multiple generations. Thus, repeatedly selecting the top 1 in 10 over ten generations (where each new generation consists of the offspring of those selected in the previous generation) will produce a much greater increase in the trait value than a one-off selection of 1 in 100. The problem with sequential selection, of course, is that it takes longer. If each generational step takes twenty or thirty years, then even just five successive generations would push us well into the twenty-second century. Long before then, more direct and powerful modes of genetic engineering (not to mention machine intelligence) will most likely be available.

There is, however, a complementary technology, one which, once it has been developed for use in humans, would greatly potentiate the enhancement power of pre-implantation genetic screening: namely, the derivation of viable sperm and eggs from embryonic stem cells.
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The techniques for this have already been used to produce fertile offspring in mice and gamete-like cells in humans. Substantial scientific challenges remain, however, in translating the animal results to humans and in avoiding epigenetic abnormalities in the derived stem cell lines. According to one expert, these challenges might put human application “10 or even 50 years in the future.”
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With stem cell-derived gametes, the amount of selection power available to a couple could be greatly increased. In current practice, an in vitro fertilization procedure typically involves the creation of fewer than ten embryos. With stem cell-derived gametes, a few donated cells might be turned into a virtually unlimited number of gametes that could be combined to produce embryos, which could then be genotyped or sequenced, and the most promising one chosen for implantation. Depending on the cost of preparing and screening each individual embryo, this technology could yield a severalfold increase in the selective power available to couples using in vitro fertilization.

More importantly still, stem cell-derived gametes would allow multiple generations of selection to be compressed into less than a human maturation period, by enabling
iterated embryo selection
. This is a procedure that would consist of the following steps:
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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 six months or less.
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3
Cross the new sperm and ova to produce embryos.

4
Repeat until large genetic changes have been accumulated.

In this manner, it would be possible to accomplish ten or more generations of selection in just a few years. (The procedure would be time-consuming and
expensive; however, in principle, it would need to be done only once rather than repeated for each birth. The cell lines established at the end of the procedure could be used to generate very large numbers of enhanced embryos.)

As
Table 5
indicates, the
average
level of intelligence among individuals conceived in this manner could be very high, possibly equal to or somewhat above that of the most intelligent individual in the historical human population. A world that had a large population of such individuals might (if it had the culture, education, communications infrastructure, etc., to match) constitute a collective superintelligence.

The impact of this technology will be dampened and delayed by several factors. There is the unavoidable maturational lag while the finally selected embryos grow into adult human beings: at least twenty years before an enhanced child reaches full productivity, longer still before such children come to constitute a substantial segment of the labor force. Furthermore, even after the technology has been perfected, adoption rates will probably start out low. Some countries might prohibit its use altogether, on moral or religious grounds.
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Even where selection is allowed, many couples will prefer the natural way of conceiving. Willingness to use IVF, however, would increase if there were clearer benefits associated with the procedure—such as a virtual guarantee that the child would be highly talented and free from genetic predispositions to disease. Lower health care costs and higher expected lifetime earnings would also argue in favor of genetic selection. As use of the procedure becomes more common, particularly among social elites, there might be a cultural shift toward parenting norms that present the use of selection as the thing that responsible enlightened couples do. Many of the initially reluctant might join the bandwagon in order to have a child that is not at a disadvantage relative to the enhanced children of their friends and colleagues. Some countries might offer inducements to encourage their citizens to take advantage of genetic selection in order to increase the country’s stock of human capital, or to increase long-term social stability by selecting for traits like docility, obedience, submissiveness, conformity, risk-aversion, or cowardice, outside of the ruling clan.

Effects on intellectual capacity would also depend on the extent to which the available selection power would be used for enhancing cognitive traits (
Table 6
). Those who do opt to use some form of embryo selection would have to choose how to allocate the selection power at their disposal, and intelligence would to some extent be in competition with other desired attributes, such as health, beauty, personality, or athleticism. Iterated embryo selection, by offering such a large amount of selection power, would alleviate some of these tradeoffs, enabling simultaneous strong selection for multiple traits. However, this procedure would tend to disrupt the normal genetic relationship between parents and child, something that could negatively affect demand in many cultures.
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With further advances in genetic technology, it may become possible to synthesize genomes to specification, obviating the need for large pools of embryos. DNA synthesis is already a routine and largely automated biotechnology, though it is not yet feasible to synthesize an entire human genome that could be used in a reproductive context (not least because of still-unresolved difficulties in getting the epigenetics right).
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But once this technology has matured, an embryo could be designed with the exact preferred combination of genetic inputs from each parent. Genes that are present in neither of the parents could also be spliced in, including alleles that are present with low frequency in the population but which may have significant positive effects on cognition.
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Table 6
Possible impacts from genetic selection in different scenarios
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One intervention that becomes possible when human genomes can be synthesized is genetic “spell-checking” of an embryo. (Iterated embryo selection might also allow an approximation of this.) Each of us currently carries a mutational load, with perhaps hundreds of mutations that reduce the efficiency of various cellular processes.
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Each individual mutation has an almost negligible effect (whence it is only slowly removed from the gene pool), yet in combination such mutations may exact a heavy toll on our functioning.
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Individual differences in intelligence might to a significant extent be attributable to variations in the number and nature of such slightly deleterious alleles that each of us carries. With gene synthesis we could take the genome of an embryo and construct a version of that genome free from the genetic noise of accumulated mutations. If one wished to speak provocatively, one could say that individuals created from such proofread genomes might be “more human” than anybody currently alive, in that they would be less distorted expressions of human form. Such people would not all be carbon copies, because humans vary genetically in ways other than by carrying different deleterious mutations. But the phenotypical manifestation of a proofread genome may be an exceptional physical and mental constitution, with elevated functioning in polygenic trait dimensions like intelligence, health, hardiness, and appearance.
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(A loose analogy could be made with composite faces, in which the defects of the superimposed individuals are averaged out: see
Figure 6
.)