Saturday links 9-Feb-2019: climate and epidemics, ur DNA r belong to us, Alzheimer’s gum disease, Aphantasia

Here’s a list of links/commentary on what I found interesting this week.

1. European arrival in Americas may have caused enough death to cool climate. When Europeans discovered America in 1492, they brought along smallpox and measles. The resulting mass epidemics killed roughly 90% of the population, dropping from 60 to 5 million. Previously cultivated land, roughly the size of France, became reforested. The new plant growth lowered CO2 levels, cooling the climate. In particular causing the temperature downturn in the 1590s. This idea has been around since 2003. A new paper adds to the argument. It’s a disturbing and headline worthy idea.

What’s certain is the mass American dying and resulting reforestation happened. And on the margin this lowered CO2 levels. Fine. What’s less certain is how big this effect was compared to everything else. The paper argues noticeably big. It’s a cool paper. The BBC news story is here. And if interested, read a critique here.

2. All ur DNA r belong to us. In April last year the police solved a murder cold case by searching GEDmatch, a public DNA database. They only found 3rd and 4th cousins, but that was enough to narrow the search to 1000 people. And from there they eventually solved the murder. GEDmatch has about a million people in it. It’s open source, in the sense that people who upload their DNA have agreed to allow anyone else to use it.

What’s new is Family Tree DNA, a consumer DNA testing company, with 2 million DNA profiles on file, has been allowing the FBI use their DNA database to find criminals. And they did this without informing their users until Buzzfeed broke the story. People are rightfully upset. This is a breach of privacy and terms of service. That said, as we saw in the GEDmatch case, the public seems generally supportive of using DNA to identify criminals. So I don’t think things won’t go back to how they were.

People believe their own DNA is private. But even though only 3% of your DNA is shared by 2nd cousins, that’s enough to identify your pedigree. And even 3rd or 4th cousins are enough to find you if the FBI is motivated enough. Given shared ancestry, DNA information is far more of public good than most naively assume. All ur DNA r belong to us.

Of course this means foreign governments can use DNA to track down relatives of dissidents, and tabloids can use DNA to snoop on celebrities. So which justifications for a search are legally allowed matters. But the larger point is we’re not heading toward a world where anyone can be tracked by their DNA. We live in such a world already.

3. Jay Rosen is worried journalism for the 2020 presidential election will be like 2016. Here’s Rosen: “it’s become clearer and clearer to me that, without intervention, coverage of the 2020 campaign is likely to be a disaster for everyone except Trump and his core voters, who want to watch it all burn anyway.” It’s hard to know what’ll happen in 2020 given how much is in flux now. But agree the dynamics around journalism and Trump are unchanged from 2016. Rosen says journalists should spend less time on horse race journalism, pumping out articles on who’s ahead and who’s behind, and spend more time focusing on issues voters care about. We’ll see. Twitter thread is here, and interview is here.

4. Gum Disease and Alzheimer’s. The more sensational version of the news was We may finally know what causes Alzheimer’s – and how to stop it. (Answer: bacteria behind gum disease). This was then countered by No, we don’t know that gum disease causes Alzheimer’s. With the subtitle “A new study suggests a link between oral bacteria and Alzheimer’s, but it’s far from proven.” Which is the correct take. As for me, am I flossing more often now? Yes. Yes I am.

5. Cowen on Pinker on the Enlightenment. Steven Pinker’s book Enlightenment Now is, in my view, excellent. But the book has been attacked for being naive. Pinker responded. Then Tyler Cowen got to the heart of the matter when he noted Pinker reserves the name Enlightenment only for those aspects he likes. Not enough grey. In particular I like this bit: “I am very much an admirer of Pinker and his work, and I consider myself an optimist, especially across longer time frames.  But what is sometimes called progress does also have a dark side, and we will do better fighting that dark side if we are clearer — in our own minds and with each other — on how things have run to date.”

6. Aphantasia, I have it. Aphantasia is an inability to visualize images in your mind’s eye. So imagine an apple. Close your eyes and see it. If you have aphantasia, you can’t do that. There are matters of degree. Some people can vividly imagine pictures. Others less clearly. But if you can’t to it at all you have aphantasia. It was a shock a few years back to read about it because, having aphantasia my whole life, I had always assumed everyone was like me, and “mind’s eye” was just a metaphor. If you’re curious, this account of how shocking it was to find out about aphantasia was similar to my own. Oh. I see. I see! So that’s why book authors waste so much time on elaborate visual descriptions of the countryside. Who knew? Remembering faces is a bit harder for me than most. I can’t visualize, but if I make an effort, or just see someone often that’s fine. GPS is a godsend. My kids sometimes complain I use it for places we’ve been many times, but I love it. And my case is relatively mild. If I focus hard I can sometimes sort of imagine seeing a picture. But it’s rarely worth the bother.

I suppose this is neither here nor there. But perhaps I wanted to share because it made me realize we can go through life assuming too much. Leading separate lives, we but dimly perceive our own mind’s eye. Best to reach out and share and learn from others, letting their outside views make us see more fully a complicated, if occasionally beautiful, world.

That’s all. Thanks for reading!