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Filter bubbles, echo chambers, and online news consumption

Filter bubbles, echo chambers, and online news consumption

  • Seth R. Flaxman – I am currently undertaking a postdoc with Yee Whye Teh at Oxford in the computational statistics and machine learning group in the Department of Statistics. My research is on scalable methods and flexible models for spatiotemporal statistics and Bayesian machine learning, applied to public policy and social science areas including crime, emotion, and public health. I helped make a very accessible animation answering the question, What is Machine Learning?
  • Sharad Goel – I’m an Assistant Professor at Stanford in the Department of Management Science & Engineering (in the School of Engineering). I also have courtesy appointments in Sociology and Computer Science. My primary area of research is computational social science, an emerging discipline at the intersection of computer science, statistics, and the social sciences. I’m particularly interested in applying modern computational and statistical techniques to understand and improve public policy.
  • Justin M. Rao – I am a Senior Researcher at Microsoft Research. A member of our New York City lab, an interdisciplinary research group combining social science with computational and theoretical methods, I am currently located at company HQ in the Seattle area, where I am also an Affiliate Professor of Economics at the University of Washington.
  • Spearman’s Rank-Order Correlation
  • Goel, Mason, and Watts (2010) show that a substantial fraction of ties in online social networks are between individuals on opposite sides of the political spectrum, opening up the possibility for diverse content discovery. [p 299]
    • I think this helps in areas where flocking can occur. Changing heading is hardest when opinions are moving in opposite directions. Finding a variety of perspectives may change the dynamic.
  • Specifically, users who predominately visit left-leaning news outlets only very
    rarely read substantive news articles from conservative sites, and vice versa
    for right-leaning readers, an effect that is even more pronounced for opinion

    • Is the range of information available from left or right-leaning sites different? Is there another way to look at the populations? I think it’s very easy to get polarized left or right, but seeking diversity is different, and may have a pattern of seeking less polarized voices?
  • Interestingly, exposure to opposing perspectives is higher for the
    channels associated with the highest segregation, search, and social. Thus,
    counterintuitively, we find evidence that recent technological changes both
    increase and decrease various aspects of the partisan divide.

    • To me this follows, because anti belief helps in the polarization process.
  • We select an initial universe of news outlets (i.e., web domains) via the Open Directory Project (ODP,, a collective of tens of thousands of editors who hand-label websites into a classification hierarchy. This gives 7,923 distinct domains labeled as news, politics/news, politics/media, and regional/news. Since the vast majority of these news sites receive relatively little traffic,
    •  Still a good option for mapping. Though I’d like to compare with
  • Specifically, our primary analysis is based on the subset of users who have read at least ten substantive news articles and at least two opinion pieces in the three-month time frame we consider. This first requirement reduces our initial sample of 1.2 million individuals to 173,450 (14 percent of the total); the second requirement further reduces the sample to 50,383 (4 percent of the total). These numbers are generally lower than past estimates, likely because of our focus on substantive news and opinion (which excludes sports, entertainment, and other soft news), and our explicit activity measures (as opposed to self-reports).
    • Good indicator of explore-exploit in the user population at least in the context of news.
  • We now define the polarity of an individual to be the typical polarity of the news outlet that he or she visits. We then define segregation to be the expected distance between the polarity scores of two randomly selected users. This definition of segregation, which is in line with past work (Dandekar, Goel, and Lee 2013), intuitively captures the idea that segregated populations are those in which pairs of individuals are, on average, far apart.
    • This fits nicely with my notion of belief space
  • ideological-segregation-across-channels
    • This is interesting. Figure 3 shows that aggregators and direct (which have some level of external curation, are substantially less polarized than the social and search-based channels. That’s a good indicator that the visible information horizon makes a difference in what is accessed.
  • our findings do suggest that the relatively recent ability to instantly query large corpora of news articles—vastly expanding users’ choice sets—contributes to increased ideological segregation
    • The frictionlessness of being able to find exactly what you want to see, without being exposed to things that you disagree with.
  • In particular, that level of segregation corresponds to the ideological distance between Fox News and Daily Kos, which represents meaningful differences in coverage (Baum and Groeling 2008) but is within the mainstream political spectrum. Consequently, though the predicted filter bubble and echo chamber mechanisms do appear to increase online segregation, their overall effects at this time are somewhat limited.
    • But this depends on how opinion is moving. We are always redefining normal. It would also be good to look at the news producers using this approach…?
  • This finding of within-user ideological concentration is driven in part by the fact that individuals often simply turn to a single news source for information: 78 percent of users get the majority of their news from a single publication, and 94 percent get a majority from at most two sources. …even when individuals visit a variety of news outlets, they are, by and large, frequenting publications with similar ideological perspectives.
  • opposingpartisanexposure
    • Although I think focussing on ‘opposing’ rather than ‘diverse’ biases these results, this still shows that populations of users behave differently, and that the channel has a distinct effect.
  • …relatively high within-user variation is a product of reading a variety of centrist and right-leaning outlets, and not exposure to truly ideologically diverse content.
    • So left leaning is more diverse across ideology
  • the outlets that dominate partisan news coverage are still relatively mainstream, ranging from the New York Times on the left to Fox News on the right; the more extreme ideological sites (e.g., Breitbart), which presumably benefited from the rise of online publishing, do not appear to qualitatively impact the dynamics of news consumption.

Some good parts, kind of integrated

We are packing up, so I’m done for now. Progress has been pretty good. The core parts of the posting module are done, though they are not yet managed by a “topic manager” or some similar. I have YUI talking via PHP to MySQL, sending objects that contain data that will be needed in a structured way. That turned out to be much harder than I thought, simply because I couldn’t make the debugger in IntelleJ work in the PHP server file in such a way that I could watch an HTTP request come in. In olden days, I would have RTFM about the process and worked from that, but now with OpenSource, I’ve become very dependent on the debugger to tell me what’s actually going on. Many times things don’t correspond with (often stale) documentation. So in the end, I put together a light PHP class that pretty much echoed POST calls back at me so that I could look at them in the JavaScript debugger. That burned a day. Sigh.

The last (new) thing to do is to make the database access robust. I did my code based on Learning PHP, MySQL, and JavaScript, a generally fine book, but it still uses the deprecated “mysql_*” calls. I need to update that and have some generalized data return structures built. Then that part should be reasonably static from here on out.

Version 1!

  • Writing out files – done with CSV, not sure if we need the xml yet. Here’s what a session result looks like:
  • Trying to copy the executable over to another machine. First, the app failed to launch until I installed the end-user directX package. Now, it fails to start the XAudio2 engine. Trying the full install.
  • Built a release version. That may be better?
  • Well, it was either the full SDK install or the release build, but it works. I’m betting that it was the release build, since the debug dlls aren’t included in the DirectX end user package and I may have been referencing those.
  • Everything is now on the laptop for tomorrow’s meeting 🙂
  • Oh yeah, and I need to change the versionversion1

Building the Audio Library

  • Making sure that the release version of the code runs as well – it does. And a massive 19kb of executable. Of course, it’s not statically linked… That makes it 6,234kb
    • C/C++
      • General
        • Additional Include Directories: $(DXSDK_DIR)\Include
      • Language
        • Treat WChar_t as Built in Type: Yes (/Zc:wchar_t)
    • Linker
      • General
        • Additional Library Directories: C:\Program Files %28×86%29\Microsoft DirectX SDK %28June 2010%29\Lib\x86
      • Input
        • Additional Dependencies:
          • winmm.lib
          • dxerr.lib
          • X3DAudio.lib (only needed for DLL compilation)
  • Making library
    • Following directions here:
    • For a DLL library, you *must* select the when creating your console application’s (that is actually not a console application, but never mind that…) “export variables” checkbox option. Still figuring out how to use this.
    • For my first attempt in accessing the DLL, I’ve created the following method (The #defines are generated, I’ve included them for all to marvel at):
        #define DXAUDIOINTERFACEDLL_API __declspec(dllexport)
        #define DXAUDIOINTERFACEDLL_API __declspec(dllimport)
        DXAUDIOINTERFACEDLL_API BasicAudio* getBasicAudio(void);
      • I think this produces an exported method that returns a pointer to the BasicAudio class. Not sure though. It may, though now I’m getting the following link errors:
        • 1>DynamicLibConsoleTest.obj : error LNK2019: unresolved external symbol “public: void __thiscall BasicAudio::destroy(void)” (?destroy@BasicAudio@@QAEXXZ) referenced in function _wmain
        • etc…
        • 1>C:\Phil\MSVC Dev\MultichannelOr3dAudio\DxAudioInterfaceLibrary\Debug\DynamicLibConsoleTest.exe : fatal error LNK1120: 6 unresolved externals
      • Which means the public inner methods are not available. Maybe the answer is to make a wrapper class for all the methods? Ugly, but something to try..
      • Building wrapper class DXAUDIOINTERFACEDLL_API CDxAudioInterfaceDLL
      • Done. Compiles and links now, but doesn’t run. Ah. I was declaring a local pointer to the internal BasicAudio class. Not pretty, but it does seem to work…
  • Testing against Static console app – check
  • Testing against Dynamic console app – check
  • Switching to Release build
  • Testing against Static console app – check
  • Testing against Dynamic console app – check
  • Checked everything into Subversion. Calling it a day.

A working console app!

Good progress today

Looks like everything is working in the proof of concept! Here’s the code:

#include "stdafx.h"
#include <Windows.h>
#include <conio.h>
#include "audio.h"

int _tmain(int argc, _TCHAR* argv[])
	int keyIn;
	HRESULT hr;                 // standard return type
	LPTSTR buf;
	LPTSTR targetDir = "C:\\Programming 2D Games in DirectX 11\\Chapter 7 - Sound\\ConsoleSound\\ConsoleSound\\ConsoleSound";
	Audio *audio = new Audio();

	buf = (LPTSTR)calloc(256, sizeof(char));
	GetCurrentDirectory(256, buf);
	printf("Current dir: '%s'\n", buf);
	if (*WAVE_BANK != '' && *SOUND_BANK != '')  // if sound files defined
		if( FAILED( hr = audio->initialize() ) )
				printf("Failed to initialize sound system because media file not found.\n");
				printf("hit return to exit\n");
				return -1;
				printf("Failed to initialize sound system.\n");
				printf("hit return to exit\n");
				return -1;

	printf("Type 'x' to quit, 1, 2, or 3 for sounds.\n");
	bool doit = true;
			keyIn = getch();

			printf("key = %c\n", keyIn);
			case 'x' : doit = false; 
			case '1' : audio->playCue(BEEP1);                  // play sound
			case '2' : audio->playCue(BEEP2);                  // play sound
			case '3' : audio->playCue(BEEP3);                  // play sound
		audio->run();                       // perform periodic sound engine tasks

	printf("hit return to exit");
	return 0;

Tomorrow, we’ll try to add positional sound.