Daniel Lemire's blog

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Science and Technology links (March 30th, 2018)

  1. People who score higher on intelligence tests tend to have larger brains. Twin studies suggest the same genetic factors influence both brain size and intelligence.
  2. The effects of campaign contact and advertising on Americans’ candidates choices in general elections is zero. A related fact: in 2016, Clinton has outspent Trump throughout the election by more than $150 million.
  3. In his article “In defense of skepticism about deep learning” (January 2018), Gary Marcus wrote “deep learning by itself, although useful, was unlikely to lead on its own to artificial general intelligence”.
  4. We want to synthesize modified versions of all the genes in the human genome in the next few years” (George Church).
  5. Chinese students get 10% of all doctorates awarded in the U.S. There are more Chinese engineers working on AI at U.S. tech companies than in all of China.
  6. Women score higher in anxiety, vulnerability, altruism, and sympathy while men score higher in excitement-seeking and openness to intellect.
  7. Alcohol consumption is positively associated with handgrip strength in the elderly. Handgrip strength is strongly correlated with life expectancy.
  8. While postdocs are necessary for entry into tenure-track jobs, they do not enhance salaries in other job sectors over time.
  9. Studies in psychology do not hold up to scrutiny:

We conducted replications of 100 experimental and correlational studies published in three psychology journals using high­-powered designs and original materials when available. Replication effects were half the magnitude of original effects, representing a substantial decline.

While 97% of the original studies had significant results only 36% of the replications had significant results. That is, given a random published study, if you bet that it is bogus, you will win most of the time.

It also seems no to matter who is doing the research:

Moreover, correlational evidence is consistent with the conclusion that variation in the strength of initial evidence (such as original P value) was more predictive of replication success than variation in the characteristics of the teams conducting the research (such as experience and expertise).

  1. You will do better if you believe that performing cognitive work energizes you to do more.
  2. It would have been better to invest all your money in gold back in 2000 than in the stock market. The same is true regarding Bitcoin from its starting point. I don’t know what it means.
  3. Almost all Economics Nobel prizes are closely related through their PhD supervisors. This is yet more evidence that “who you know” is really important to your intellectual productivity.
  4. Canada celebrates its 150th birthday by creating several prestigious research chairs (via Antonio Badia).1. Our ancestors had sex with the Neanderthals and the Denisovans.
  5. Obesity is a recent phenomenon:

Between the birth cohorts of 1930 and 1993, the prevalence of obesity rose from 0 to 14% among boys and from 2 to 12% among girls. (…) Among boys, all these increases began after birth year 1970. Among girls, obesity began to rise after birth year 1980 (…).


While it may be true that body mass indexes (BMIs) have been increasing slowly for a long time, the increases observed in recent decades are much faster and have pushed many adults and children over the obesity threshold in a remarkably short time. The trend is distressing, but to reverse it we only need to turn the clock back to 1980. We don’t need to go back to 1900.

  1. Rats did not spread the plague:

While it is commonly assumed that rats and their fleas spread plague during the Second Pandemic, there is little historical and archaeological support for such a claim. Here, we show that human ectoparasites, like body lice and human fleas, might be more likely than rats to have caused the rapidly developing epidemics in pre-Industrial Europe.

  1. Alzheimer’s disease can be spared by nonsteroidal anti-inflammatory drugs. In other words, it could be that aspirin keeps you sharp.