Explain it to me like I’m five years old

Written by: Stephen Hsu

Primary Source:  Information Processing

Explain it to me like I’m five years old

An MIT Technology Review reporter interviewed me yesterday about my Nautilus Magazine article Super-Intelligent Humans Are Coming. I had to do the interview by gchat because my voice is recovering from a terrible cold and too much yakking with brain scientists at the Allen Institute in Seattle.

I realized I need to find an explanation for the thesis of the article which is as simple as possible — so that MIT graduates can understand it ;-)

Let me know what you think of the following.

1. Cognitive ability is highly heritable. At least half the variance is genetic in origin.

2. It is influenced by many (probably thousands) of common variants (see GCTA estimates of heritability due to common SNPs). We know there are many because the fewer there are the larger the (average) individual effect size of each variant would have to be. But then the SNPs would be easy to detect with small sample size.

Recent studies with large sample sizes detected ~70 SNP hits, but would have detected many more if effect sizes were consistent with, e.g., only hundreds of causal variants in total.

3. Since these are common variants the probability of having the negative variant — with (-) effect on g score — is not small (e.g., like 10% or more).

4. So each individual is carrying around many hundreds (if not thousands) of (-) variants.

5. As long as effects are roughly additive, we know that changing ALL or MOST of these (-) variants into (+) variants would push an individual many standard deviations (SDs) above the population mean. Such an individual would be far beyond any historical figure in cognitive ability.

Given more details we can estimate the average number of (-) variants carried by individuals, and how many SDs are up for grabs from flipping (-) to (+). As is the case with most domesticated plants and animals, we expect that the existing variation in the population allows for many SDs of improvement (see figure below).

For references and more detailed explanation, see On the Genetic Architecture of Cognitive Ability and Other Heritable Traits.

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Stephen Hsu
Stephen Hsu is vice president for Research and Graduate Studies at Michigan State University. He also serves as scientific adviser to BGI (formerly Beijing Genomics Institute) and as a member of its Cognitive Genomics Lab. Hsu’s primary work has been in applications of quantum field theory, particularly to problems in quantum chromodynamics, dark energy, black holes, entropy bounds, and particle physics beyond the standard model. He has also made contributions to genomics and bioinformatics, the theory of modern finance, and in encryption and information security. Founder of two Silicon Valley companies—SafeWeb, a pioneer in SSL VPN (Secure Sockets Layer Virtual Private Networks) appliances, which was acquired by Symantec in 2003, and Robot Genius Inc., which developed anti-malware technologies—Hsu has given invited research seminars and colloquia at leading research universities and laboratories around the world.