You've probably seen it on the bestsellers list already, but The Dark Knight, the biggest movie of the year (of the last several years really, since Titanic), is coming out on December 9 and is now available for pre-order on two-disc Blu-ray, two-disc special edition DVD, widescreen single-disc DVD, and full-screen single-disc DVD.  Here are some advance specs we've gotten for the special features:

Blu-ray:

• Movie with Focus Points (picture in picture)
• BD Live
• Gotham Uncovered: Creation of a Scene: Director Christopher Nolan and creative collaborators unmask the incredible detail and planning behind the film, including stunt staging, filming in IMAX®, and the new Bat-suit and Bat-pod.
• Batman Tech: The incredible gadgets and tools (in HD)
• Batman Unmasked: The Psychology of The Dark Knight: Delve into the psyche of Bruce Wayne and the world of Batman through real-world psychotherapy (in HD)   
• Gotham Tonight: 6 episodes of Gotham Cable's premier news program 
• The Galleries: The Joker cards, concept art, poster art, production stills, trailers and TV spots
• Digital Copy of the feature film

Two-disc DVD:

• Gotham Uncovered: How Christopher Nolan and his team developed the new Bat-suit and Bat-pod and composer Hans Zimmer musically characterized the Joker’s reign of chaos.
• The Dark Knight IMAX® Scenes: View these 6 action-packed sequences--shot on the largest format possible--in their original IMAX framing, just as they were intended
• Gotham Tonight: 6 episodes of Gotham Cable's premier news program 
• The Galleries: Poster art and production stills
• Digital Copy of the feature film

--David

Related links in our blog:

• See The Dark Knight in IMAX, if You Can
• BD Live

For a social network scientist, Amazon is a great sandbox for experimenting and searching for interesting patterns! 

I started mapping book networks in the last century. It was 1998 when an on-line conversation raised my curiosity. Here is the original white paper I wrote about that initial investigation.

After the late Tim Russert brought us the "red states – blue states" meme during the 2000 election I started to investigate patterns of political books. I tried various data collection techniques and found an interesting outcome –- no matter how I collected the data I ended up with highly similar patterns. I use snowball sampling  -- start at a known point and follow the data out 1 or 2 steps. Once the snowball sample is complete, I start to eliminate the noise in the network -– I want to find the strong patterns that multiple overlapping networks provide. When the patterns emerge I usually see two strong clusters, with a minor cluster or scattering of books between the two large components. I only color the components after my network analysis software finds the emergent groups in the data –- then it is obvious which cluster is blue and which is red.

Below is the first political book map I published on my web site. It showed the famous red-blue divide that had become common wisdom by 2003. It was ironic, and a commentary on our situation, that the center book -– holding both sides together -– was titled: What Went Wrong!

The sharp left-right divide remained in place for the 2004 US presidential election. Below are two graphs of the same data. The first graph is the emergent cluster view –- those similarly connected are closer together. This map was done about 1 year after the 2003 map above. They both contain many different books, yet reveal a very similar pattern and a strong divide.

The second view is of the very same data as above. This view was made after the emergent view showed us who was in which cluster. This view accentuates the divide by putting each side into facing arcs and then sorting the books alphabetically for easy reference. As in the diagram above most links are within the cluster with no direct links between clusters, only through 3 intermediary books that ended up spanning the boundary between red and blue.

During the 2008 US presidential election we expected a different pattern to appear. After all both candidates were initially talking of bridging the divide and the 2006 mid-term elections showed us several examples where the strong boundaries were becoming more fuzzy. The blues and the intermediates [often books outside of 2-party mainstream thinking] started to overlap. Ron Paul, Jesse Ventura, and Lou Dobbs were finding more blue readers than red readers. 

The map below was done just before the two major party conventions in 2008. We again see: different books, same pattern. We also now see [based on on current snowball sampling scheme] that the left reads a greater number of books than the right. This map does not indicate volume or quantity of sales. It is very possible that the right buys more books of a more focused set. As a general rule we do not compare quantities of books sold, we just use it a bar to include/exclude books in our starting sample -– a top % of Amazon’s bestsellers are chosen as our starting point. Our maps reflect patterns found in the bestsellers on Amazon –- we do not know what is happening amongst low volume books. Our maps capture the most common patterns.

As we have witnessed, after both national conventions this summer, there is still a strong and vocal divide between red and blue. The war of words and accusations grows louder as election day draws nearer. Arms merchants do well in times of war –- no matter if the ammunition are bullets or words! --Valdis Krebs

See the whole Red-Blue Roundtable

Voting is simple... precinct, district, state, add 'em up, send 'em in. Outside of Florida 2000 and Ohio 2004 this hierarchy of geographical boxes works well. Boxes are simple, you are either in this one or that one, or not eligible to play. Simple clear rules. Simple clear math.

We vote in boxes, but most of us don't think in boxes. We think in networks -- those near to us [in social, not physical distance] influence what we know, how we think, and who we vote for. We are social animals, not logical animals, nor economically maximizing animals. Many vote against their economic self-interest. Many make illogical choices... or so it appears.

Are we stupid? Are we sheep? Are we random? Our behavior often appears that way -- especially to outsiders who do not know the social ecosystem we are embedded in. Political pundits often get voting behavior wrong because they look at voters as independent, logical, demographically-driven, self-maximizing individuals. They miss the 800-pound gorilla in the room -- various social networks and their power to influence behavior and overwhelm demographics, economics, and geography.

Birds of a feather flock together. This is a strong driver of human behavior and found throughout living systems in nature. Besides being a fascinating read, The Big Sort is a verifiable and happening dynamic.  Yet, we will never live in totally homogenous tracts bereft of diversity. Even if we appear to do so on the surface -- "gee, they all look and dress the same" -- our largely invisible social ties may not be so homophilous. 

Simple organizing systems such as hierarchies and neighborhoods are never as they appear on the surface. Below is a picture of a corporate hierarchy -- simple reporting relationships, everyone in their own group. Blue nodes are managers, green nodes are directors, and the magenta colored node is the VP. It could be a picture of our state political structure. Precincts reporting into districts reporting into the state. Or broken down further, households into neighborhoods, into precincts. The simple organized hierarchy of boxes.

The hierarchy below is viewed as a hub-and-spoke network, or tree, with the black lines showing reporting relationships and gold boxes being either departments or districts.

In organizations we know that the interesting stuff -- learning, innovation, adaption -- usually does not happen within formal reporting structures. The good stuff happens in the "white space" on the organization chart -- between boxes, across groups, spanning boundaries. The invisible network that permeates every organization and every neighborhood is shown by the grey links below. Of course, in the age of the internet many of these grey lines cover large geographical distance.

Votes are counted along the black links in the hierarchy, but votes are created, influenced and reinforced along the grey links which represent overlapping social networks that we are all embedded in. Our friends, family, and colleagues, who influence our vote, are distributed through many neighborhoods, precincts, districts, and states near and far. This is why it is not only important to look at quantity of book sales by geography, but to look at networks of books and how they reveal the influence factors in each of our political sense-making processes.

Networks of books?  Do books have a social life?  Not really, but Amazon provides us data to evaluate book purchases as a social system. Amazon's consistent feedback on every product page -- people that bought [this] also bought [those] –- allows us to create a social network of books. Of course what we are really evaluating are not the social dynamics of books but the social dynamics of buyers and readers of those books –- all without revealing the identity of the Amazon customers making their consumer choices.

So, what do you think our network of books will reveal for this election? --Valdis Krebs

See the whole Red-Blue Roundtable

A conversation between a pollster, a journalist, and a professor seems like a great idea--we all do research, but using different methods and with different goals. But in this particular forum we seem to have been talking past each other, with Zogby emphasizing how most Americans have a fundamental non-ideological view of policy, Bishop talking about partisan divisions, and me going on about red and blue states. Perhaps our areas of expertise are just too far apart. Nonetheless, I will try one more time to make some linkages. I am interested to hear my co-discussants' views on these issues.

As I noted in my earlier entry to this discussion, I think Zogby's and Bishop's positions can be reconciled. Zogby's approach "has been to find broad areas of commonality, the overarching groupings that tens of millions of Americans find themselves in," while Bishop says that Americans are "sorting by economy, by ways of life, by education, by belief and, only every election day, by politics."

How can both these statements be true?  Most obviously, there can be unity across population groups amid geographic separation. It is easier than before to communicate with people who live in other cities; in my own world of academia, many have noted the transferring of allegience of faculty from their university where they work to the academic "field" they inhabit.

Beyond this, surveys have repeatedly found that most Americans have moderate views on issues (as shown in the distributions of ideological positions displayed in my previous entry) and also are not particularly ideological, in that it is not particularly easy to predict views on one issue from views on another. As we say in our book, each person maintains a mix of attitudes within himself or herself. For instance, 40% of Americans in a 2004 survey labeled themselves as Republican, but only 23% identified themselves as both Republican and conservative.

Almost half of Republicans do not describe themselves as being ideologically conservative. If we also consider issue preferences, the constraint of people's political preferences looks even weaker. Only 6% of respondents were Republicans who think of themselves as conservatives, oppose abortion, and have conservative views on affirmative action and health policy. Fully 85% of self-declared Republicans are nonconservative or take a nonconservative stand on at least one of these three traditional issues.

A similar picture emerges if we look at Democrats. In this case, of the 49% self-declared Democrats in the sample, only 36% call themselves liberals. Overall, almost 90% of Democrats are nonliberal or have nonliberal views on abortion, affirmative action, or health policy.

These numbers should not be surprising, given that in general, the correlation between party identification or ideology and opinion on political issues is low. Knowing somebody's political identification increases our chances to guess his or her issue preferences, but not by much. This supports Zogby's view of Americans as nonideological and Bishop's view of sorting based on lifestyle rather than politics.

So, yes, most people are not consistently ideological in their attitudes. But people have strong views about the Democratic and Republican parties. Higher-income Americans in red states have distinctly different views than higher-income Americans in blue states.  See this graph, which shows average ideological positions (as estimated from survey questions on economic and social issues) among poor, middle-income, and rich voters in red, purple, and blue states:

The higher the income level, the more distinct are the residents of red and blue states. This doesn't contradict Zogby's point that most Americans are broadly in the political center; it just shows that the distinctions that do exist manifest themselves geographically. It is a challenge of politicians, when campaigning, to make the most of these divisions and, when governing, to find the underlying unity. --Andrew Gelman

See the whole Red-Blue Roundtable

Bill Bishop and John Zogby both point out that there are important divisions within as well as between states. Bishop focuses on partisan divisions distinguishing his blue neighborhood of Travis Heights from bright red areas nearby in Texas, contrasts that appear in voting patterns, political contributions, and social attitudes such as gay marriage. Zogby is more interested in cross-cutting categories such as economic winners in growing states, or people falling behind in declining states: these are groups that are not clearly tied to one party or another.

I attribute part of the difference in focus between Bishop and Zogby to their different goals: Bishop is interested in America's political divisions and thus writes about the increasing number of local areas that are becoming politically more monochromatic. In contrast, Zogby, as a pollster, is particularly interested in groups of people who can be persuaded--swing voters--and their relation to the economy, which remains the most important issue in deciding people's votes.

As a result of these different focuses, Bishop sees Americans as divided whereas Zogby sees the country as fundamentally centrist. What do the data say?

There's truth in both Bishop's and Zogby's perspectives; it all depends on how you slice the population. First, in defense of Bishop's view of polarization, there's lots of evidence that partisanship is much more ideological than it used to be. For example, here are the average positions of self-declared Democrats, Republicans, and independents on the issue of abortion:

As late as the Reagan years, the parties were indistinguishable on abortion. As we discuss in chapter 8 of our Red State, Blue State book, voters have become polarized in their attitudes to their parties and in economic, social, and foreign policy issues, in a way that they weren't, 30 or 50 years ago.

Yes, the voters are divided by party. But where do they stand on the issues? Here, Zogby's hypothesis of moderation is supported by detailed modeling of survey data. When we put voters and congressmembers on a single left-right scale, we found that most voters are in the middle with their elected representatives sitting to their left and right:

These ideologies are not self-declared "liberalism" or "conservatism"--we don't necessarily trust responses on these politically-loaded terms--but are estimated from positions on a bunch of issues. In the book, we also break these down by Democratic, Republican, and battleground states.

Finally, I read with interest Bishop's description of geographical and ideological sorting, and I'd only like to add that this sorting is predominantly being done by upper-income Americans. It's hard to get precise data on political affiliation and mobility, but I suspect it's the richer people who are more able to pick neighborhoods and "decamp for more politically hospitable environs." These are the people who are making red America red and blue America blue, and forming the patterns we see on the Amazon map and elsewhere. --Andrew Gelman

See the whole Red-Blue Roundtable.