13th April 2019, 3 min read

Science and Technology links (April 13th 2019)

1. There is little evidence that digital screens are harmful to teenager’s mental health. If there is an effect, it is small.
2. Cotton bags must be reused thousands of times before they match the environmental performance of plastic bags. Organic cotton bags are much worse than regular ones, requiring 20,000 reuse instead of only 7,000, due to the lower yield of organic farming. Cotton bags cannot be recycled. Paper bags must be reused dozens of times to have the same environmental impact as single-use plastic bags. For extra points, compute how many years you need to use an organic cotton bag, at a rate of two utilization a week, to use it 20,000 times. Why are we outlawing plastic bags, and not reusable organic cotton bags?
3. I never understood the appeal of artificial-intelligence system that take very little input from human beings (self-taught software). Rich Sutton makes a powerful case for it:
   

The bitter lesson is based on the historical observations that 1) AI researchers have often tried to build knowledge into their agents, 2) this always helps in the short term, and is personally satisfying to the researcher, but 3) in the long run it plateaus and even inhibits further progress, and 4) breakthrough progress eventually arrives by an opposing approach based on scaling computation by search and learning.

To put it another way, our most powerful weapon for ‘smarter’ software is to design systems that get better as we add more computational power, and then to add the computational power.

The net trend is to build software that looks more and more like ‘brute force’ at a high level, but with increasing sophistication in the computational substrate to provide the necessary brute force.

1. Goldstein, Qvist and Pinker make a powerful case for nuclear power in the New York Times. Nuclear power is safe, clean, relatively inexpensive and environmentally friendly. Renewal energies are not the solution despite all the propaganda at the moment:
   

Where will this gargantuan amount of carbon-free energy come from? The popular answer is renewables alone, but this is a fantasy. Wind and solar power are becoming cheaper, but they are not available around the clock, rain or shine, and batteries that could power entire cities for days or weeks show no sign of materializing any time soon. Today, renewables work only with fossil-fuel backup. Germany, which went all-in for renewables, has seen little reduction in carbon emissions.

1. Human beings have better color perception than most other mammals.
   

Humans, some primates, and some marsupials see an extended range of colors, but only by comparison with other mammals. Most non-mammalian vertebrate species distinguish different colors at least as well as humans, and many species of birds, fish, reptiles and amphibians, and some invertebrates, have more than three cone types and probably superior color vision to humans.

So why would human beings have superior color vision compared to other mammals?

A recent evolutionary account posits that trichromacy facilitates detecting subtle skin color changes to better distinguish important social states related to proceptivity, health, and emotion in others.

1. As you age, your working memory degrades. A Nature article reports on how this can be reversed with electric brain stimulation.
2. Genetically modified plants (GMOs) have reduced pesticide use by 37% while improving yields by 22%. Though no new technology is free from risk, neither lower yields nor higher pesticide use are free from risk.
3. The poverty rate in China went from 34.5% of the population to 0.7% of the population between 2001 and 2015.