The mathematics of opinion formation

Here’s something to drive innumerate spin-doctors wild: a mathematical theory of opinion formation by Fang Wu and Bernardo Huberman of HP Labs. Abstract reads:

We present a dynamical theory of opinion formation that takes explicitly into account the structure of the social network in which individuals are embedded. The theory predicts the evolution of a set of opinions through the social network and establishes the existence of a martingale property, i.e. that the expected weighted fraction of the population that holds a given opinion is constant in time. Most importantly, this weighted fraction is not either zero or one, but corresponds to a non-trivial distribution of opinions in thelong time limit. This coexistence of opinions within a social network is in agreement with the often observed locality effect, in which an opinion or a fad is localized to given groups without infecting the whole society. We verified these predictions, as well as those concerning the fragility of opinions and the importance of highly connected individuals in opinion formation, by performing computer experiments on a number of social networks.

So now you know. The paper has lots of nice equations of the kind that make some people’s eyeballs revolve. But, at heart, it reaches reassuringly obvious conclusions. For example,

Our theory further predicts that a relatively small number of individuals with high social ranks can have a larger effect on opinion formation than individuals with low rank. By high rank we mean people with a large number of social connections. This explains naturally a fragility phenomenon frequently noted within societies, whereby an opinion that seems to be held by a rather large group of people can become nearly extinct in a very short time, a mechanism that is at the heart of fads.

These predictions, which apply to general classes of social networks, including power-law and exponential networks, were verified by computer experiments and extended to the case when some individuals hold fixed opinions throughout the dynamical process. Furthermore, we dealt with the case of information asymmetries, which are characterized by the fact that some individuals are often influenced by other people’s opinions while being unable to reciprocate and change their counterpart’s views.

Gadget wars (contd.)

Bah! Quentin has a new toy.

It’s the Sony PRS – the Portable Reader System – which is a bit like a giant read-only PalmPilot that uses the new e-Paper type display. It’s designed to be a replacement for a paperback – a way of viewing eBooks, and unlike some earlier devices, it’s not limited to DRM-encoded books downloaded from the manufacturer. You can put text files, RTF files, PDF files on it as well, and they look gorgeous.

However, there was a big question-mark over my purchase, which was that there is no official Mac or Linux support for this device. You can use a card reader to plug an SD card into your Mac, copy the files onto it and then plug it into the PRS, but that’s hardly convenient, especially in comparison to the (optional) USB docking station. Sadly, the PRS doesn’t just appear as a USB storage device. You can run the Sony software just fine under Windows using Parallels, but that’s yucky too…

Needless to say, he’s hacked it. He’s found a way to take an arbitrary document on his Mac and make it available as a pdf on the Sony device. See the full post for the grisly details.

Later… And to add insult to injury, he’s put Memex on it!

US generals ‘will quit’ if Bush orders Iran attack

From today’s Times Online

SOME of America’s most senior military commanders are prepared to resign if the White House orders a military strike against Iran, according to highly placed defence and intelligence sources.

Tension in the Gulf region has raised fears that an attack on Iran is becoming increasingly likely before President George Bush leaves office. The Sunday Times has learnt that up to five generals and admirals are willing to resign rather than approve what they consider would be a reckless attack.

“There are four or five generals and admirals we know of who would resign if Bush ordered an attack on Iran,” a source with close ties to British intelligence said. “There is simply no stomach for it in the Pentagon, and a lot of people question whether such an attack would be effective or even possible.”

A British defence source confirmed that there were deep misgivings inside the Pentagon about a military strike. “All the generals are perfectly clear that they don’t have the military capacity to take Iran on in any meaningful fashion. Nobody wants to do it and it would be a matter of conscience for them…

Server power

A new study by the Lawrence Berkeley National Laboratory (pdf available here) finds that:

Aggregate electricity use for servers doubled over the period 2000 to 2005 both in the U.S. and worldwide Almost all of this growth was the result of growth in the number of the least expensive servers, with only a small part of that growth being attributable to growth in the power use per unit.

Total power used by servers represented about 0.6% of total U.S. electricity consumption in 2005. When cooling and auxiliary infrastructure are included, that number grows to 1.2%, an amount comparable to that for color televisions. The total power demand in 2005 (including associated infrastructure) is equivalent (in capacity terms) to about five 1000 MW power plants for the U.S. and 14 such plants for the world. The total electricity bill for operating those servers and associated infrastructure in 2005 was about $2.7 B and $7.2 B for the U.S. and the world, respectively.

Nicholas Carr comments:

The estimate that servers account for 1.2 percent of overall power consumption in the U.S. is, as the San Francisco Chronicle reports, considerably lower than some previous estimates, which put data center power consumption as high as 13 percent of total U.S. consumption. It should be noted that the study, underwritten by AMD, looks only at power consumption attributable to servers, which represents about 60% to 80% of total data center power consumption. Electricity consumed by storage and networking gear is excluded. The study also excludes custom-built servers, such as the ones used by Google. The number of servers Google runs is unknown but is estimated to be in the hundreds of thousands.

It all goes to explain why Sergey Brin & Co are getting so exercised about power consumption.

Posted in Web

The movie magic is gone

Nice post-Oscars meditation by Neal Gabler in the LA Times on the way movies are moving from the centre of American popular culture towards the periphery.

What is happening may be a matter of metaphysics. Virtually from their inception, the movies have been America’s primary popular art, the “Democratic Art,” as they were once called, managing to strike the American nerve continuously for decades. During the 1920s, nearly the entire population of the country attended the movies weekly, but even when attendance sank in the 1950s under the assault of television and the industry was virtually on life support, the movies still managed to occupy the center of American life.

Movie stars have been our brightest icons. A big movie like “The Godfather,” “Titanic” or “Lord of the Rings” entered the national conversation and changed the national consciousness. Movies were the barometers of the American psyche. More than any other form, they defined us, and to this day, the rest of the world knows us as much for our films as for any other export.

Today, movies just don’t seem to matter in the same way — not to the general public and not to the high culture either, where a Pauline Kael review in the New Yorker could once ignite an intellectual firestorm. There aren’t any firestorms now, and there is no director who seems to have his finger on the national pulse the way that Steven Spielberg or George Lucas did in the 1970s and 1980s. People don’t talk about movies the way they once did. It would seem absurd to say, as Kael once did, that she knew whether she would like someone by the films he or she liked. Once at the center, movies increasingly sit on the cultural margins.

This is both a symptom and a cause of their distress. Two years ago, writing in these pages, I described an ever-growing culture of knowingness, especially among young people, in which being regarded as part of an informational elite — an elite that knew which celebrities were dating each other, which had had plastic surgery, who was in rehab, etc. — was more gratifying than the conventional pleasures of moviegoing.

In this culture, the intrinsic value of a movie, or of most conventional entertainments, has diminished. Their job now is essentially to provide stars for People, Us, “Entertainment Tonight” and the supermarket tabloids, which exhibit the new “movies” — the stars’ life sagas…

Kazaa boys going straight too…

It’s catching. After the BitTorrent announcement come this York Times story.

But with their latest creation, a Web video venture called Joost, Mr. Friis and Mr. Zennstrom, who were behind the file-sharing service Kazaa and the Internet telephone service Skype, are doing everything by the book. Revenue-sharing agreements have been signed. Licenses have been granted.

“The reason we’re doing this is because of our history,” Mr. Friis said in a telephone interview last week. “We know how these things work. And above all, we know that we don’t want to be in a long, multiyear litigation battle.”

On this day…

… in 1991, President George Bush Snr declared that “Kuwait is liberated, Iraq’s army is defeated,” and announced that the allies would suspend combat operations at midnight. They could have gone all the way to Baghdad and overthrown Saddam, but they didn’t — because the president and his advisers knew they had done no planning for the aftermath. Also, they didn’t have a UN mandate for it. What a difference an election makes.

Here we go again

From BBC Online

Jesus had a son named Judah and was buried alongside Mary Magdalene, according to a new documentary by Hollywood film director James Cameron.

The film examines a tomb found near Jerusalem in 1980 which producers say belonged to Jesus and his family.

Speaking in New York, the Oscar-winning Titanic director said statistical tests and DNA analysis backed this view…

Ye Gods! Or should it be Ye God?

Life-Long Computer Skills

This is an old story — the scandal of the ICT curriculum in schools. (I’ve ranted on about it before.) Now Jakob Nielsen’s having a go

I recently saw a textbook used to teach computers in the third grade. One of the chapters (“The Big Calculator”) featured detailed instructions on how to format tables of numbers in Excel. All very good, except that the new Excel version features a complete user interface overhaul, in which the traditional command menus are replaced by a ribbon with a results-oriented UI.

Sadly, I had to tell the proud parents that their daughter’s education would be obsolete before she graduated from the third grade.

The problem, of course, is in tying education too tightly to specific software applications. Even if Microsoft hadn’t turned Excel inside out this year, they would surely have done so eventually. Updating instructional materials to teach Office 2007 isn’t the answer, because there will surely be another UI change before today’s third graders enter the workforce in 10 or 15 years — and even more before they retire in 2065.

There is some value in teaching kids skills they can apply immediately, while they’re still in school, but there’s more value in teaching them deeper concepts that will benefit them forever, regardless of changes in specific applications.

Teaching life-long computer skills in our schools offers further benefit in that it gives students insights that they’re unlikely to pick up on their own. In contrast, as software gets steadily easier to use, anyone will be able to figure out how to draw a pie chart. People will learn how to use features on their own, when they need them — and thus have the motivation to hunt for them. It’s the conceptual things that get endlessly deferred without the impetus of formal education…

He goes on to list the kind of conceptual skills he has in mind. Useful essay.