Saturday, December 18, 2010

What "The People" "Want", Part Three: Voting Rules Gone Bad

Last time, I introduced Arrow's Theorem, which states, essentially, that we can't have our voting cake and eat it too. I also showed how plurality rule fails to give us one thing we’d like, transitivity.
Today I want look at the other classic problem: the Borda count and independence of irrelevant alternatives. First, let's review a little bit.

Tuesday, December 7, 2010

Feeling Blue? Try a Dose of Blue Light at New Scientist

After a bit of a lull, it's been a busy week (and day) at Nathan Explains Science. This afternoon I have a new story over at New Scientist (link below) on using a blue-light activated, algae-derived protein called Channel Rhodopsin 2 (ChR2) to cure depression in mice.

Fielding Reader Questions: The Strength of Voter Preference

Reader F. Tyler asks the following (slightly edited) question regarding the Borda count, a voting method in which people rank alternatives, higher-ranked alternatives get fewer points, and the option with the fewest points wins, just like golf (see this post and its follow-up on basic problems with voting):

What "The People" "Want", Part Two: It Gets Worse.

Last time I talked about what the people want, there were two main points.

First, there are always more than two options. The point of this is that if even in seemingly two-party systems such as that here in the US, there are so-called third parties, and the presence of third-party candidates is sometimes consequential. The big scary example is Allende in Chile in the 1970s; the less scary but more proximate example (for US readers) is Perot in the 1992 US presidential election.

Second, once there are more than two options, what the people "want" is hard to define. Using the Borda count and plurality rule voting methods, I showed how society's first choice depends on the manner in which people decide.

In the academic literature on "social choice," as it's called, the issue is one of preference aggregation and whether it's possible to aggregate preferences in a rational, fair way.

Today, I'll start with a statement of Arrow's Theorem, which answers that question with a resounding "No, it's not possible. Sorry." I'll follow with some intuition, and in future posts I'll flesh out the ideas.

Monday, December 6, 2010

Light "Flight" at ScienceNOW

Nifty brief on using the momentum carried by light rays to get a piece of glass to move perpendicular to the light. Puzzled? Read more here. I'll give a more thorough explanation later today.

- Posted using BlogPress from my iPhone

Monday, November 29, 2010

Some Questions For You, The Reader

There's this recurring question, "what is political science good for?" Between that and a conversation I had with members of a writer's group, to which I belong, got me interested in how the public views (political) science and how that compares with how (political) scientists view it.

Wednesday, November 24, 2010

Black Holes and Extra Dimensions

Cool (and wacky) new story on using Sgr A*—the supermassive black hole at the center of our galaxy, rather than the one in that Muse song—and gravitational lensing to search for extra dimensions.

Fun fact: I did final edits on this story over the phone this morning while we were driving north on the Grapevine section of I-5.

- Posted using BlogPress from my iPhone

Monday, November 22, 2010

DST may hurt SATs at ScienceNOW

A quick story about how Daylight Saving Time might hurt your SAT scores. Watch out, seniors.

Sports fans: the authors were John Gaski of Notre Dame and Jeff Sagarin of Sagarin Computer Sports Ratings, which I gather is something of a big deal.

Saturday, November 20, 2010

What The Bay Area "Wants": A Case Study

I thought this story in the LA Times made for an interesting case study given my post from the other day. See what comes to mind when you read it.

Wednesday, November 17, 2010

What "The People" "Want", Part One: It Depends

Now that the election is fading from your memories—and I assure you it is—I thought I’d kick off what I hope will be a series of semi-regular posts on how elections really work. 

Friday, November 12, 2010

Tuesday, November 9, 2010

In the meantime...Daryl Bem

I'm working on a number of things at the moment, but in the meantime I want to draw your attention to Jon Wilkins's post on the incredibly weird things Daryl Bem has been up to. Jon understates a little how famous Bem is in social psychology circles—he is absolutely huge. He is first-year social psychology material, literally.

Saturday, November 6, 2010

Is Cesar Millan More Dangerous Than O'Reilly and Olbermann?

Fox News probably won’t turn you into a neocon wingnut, and MSNBC probably won’t turn you into a left-coast hippie either, but The Dog Whisperer might turn your political brain to mush. That’s a scary thought given trends that suggest more and more people are turning out to vote while avoiding news.

Friday, November 5, 2010

More Evidence for Hidden Particles? at ScienceNOW

I have a new story up on some new results coming out of the MiniBooNE experiment at Fermilab. Check it out here: More Evidence for Hidden Particles?

Thursday, November 4, 2010

Nathan hopes to explain science and do some other stuff while he's at it

At the encouragement of a number of people, I'm starting the completely unpretentiously titled Nathan Explains Science for several purposes.

First, this gives me an place to tell you about science news that I think is interesting but that isn't necessarily going to get published in Science News or Nature's news section. For a variety of reasons, social science news especially doesn't get discussed as science, and that's unfortunate because there are scientific results coming out of psychology, political science, and economics that are vitally important for understanding the problems we face and the solutions we should pursue. In fact, there are a lot of old results that people should know about but don't because social science news seems less attractive than, say, finding a galaxy farther away than any other.

Second, this gives me a place to be a bit more conversational in tone, which I think makes it easier for me to explain science. Space considerations and other reasons often mean that science news outlets never get around to telling you about cool stuff like SO(3) symmetries in nature and their role in theoretical physics. I want to tell you what that is, why it's important, and why it's awesome. (It's the set of rotation symmetries in three dimensions, and it's important because it's a fundamental symmetry of nature—no matter which way you face, the laws of physics are the same. Symmetries like that matter because through a result called Noether's Theorem they imply conservation laws such as conservation of energy, which, you know, underlies almost all of our understanding of physics.)

Third, this gives me a place to advertise stories I write for other publications. So far, there are four of those:

Finally, as a scientist and especially as a political scientist, I see a lot of news stories that make me think the public (and journalists) don't really understand what science is, what it tells us, and what it's good for. This is especially true for social science—people really don't understand things like why government often seems unable to give us clean air or what the consequences of leverage in financial markets are. So I will spend some time commenting on the news when science of one sort or another helps us understand it.

Above all, I hope to convey my excitement for science and my belief that understanding the world through science is both fun and valuable to people like you. I am hopeful that isn't a pretentious aim.

Stay tuned for a post on the actual effects of Fox News on your political beliefs, and please tell your friends!

P.S. I'm using Google's AdSense in the perhaps vain hope of generating income. We'll see how it goes. If you find it annoying, please tell me, because the last thing I want to do is annoy you.