New algorithm based on biased assimilation models society polarization

Apr 01, 2013 by Andrew Myers

Anyone who has spent more than a few minutes watching some of the more partisan "news" networks lurking in the bowels of cable television is aware that America has grown more polarized in recent years. What's not so certain is why. In a paper published online March 27 in the Proceedings of the National Academy of Sciences (PNAS), a team of researchers at Stanford has devised a mathematical model that helps demonstrate what's behind the growing rift.

Hint: It's you, not them.

"We believe that is less a reflection on the state of our society, but instead stems from the process people go through to form opinions," said Ashish Goel, a professor in the Department of and Engineering (MS&E) and co-author of the paper.

Prevailing theories

The prevailing sociological theory, known as homophily, is that like seeks like. Those who have similar opinions tend to aggregate together and reinforce opinions that grow more divergent from the center over time. This is the echo chamber model that would seem to gain validation in the era of talk radio, cable news and the Internet.

According to this theory, we are polarized precisely because we have greater ability to choose our social networks and news sources. We narrowly tailor our information sources by selecting them based on how closely they mirror our own tastes.

Mathematical models that try to use homophily to explain polarization have come up short, however. Most are based on something known as De Groot's model that assumes that people form opinions in a way that minimizes overall disagreement within their network of friends and relations. As a result, an individual's opinion gradually converges to an average of those in his or her network, or so the theory goes. The flaw in these models is that they predict that opinions in society as a whole can only become more uniform over time, resulting in depolarization rather than polarization.

"We show that repeated averaging of opinions always results in less divergent opinions, even in networks where the people are like-minded," said Pranav Dandekar, a doctoral candidate in MS&E and a co-author on the paper. "You can't create outliers by averaging."

A different approach

The Stanford team instead took a different approach based on a phenomenon well known in the social sciences called biased assimilation. In biased assimilation people more easily accept evidence that supports their opinion and, likewise, are prone to discredit evidence that does not fit. More specifically, people look at inconclusive evidence in a way that is most favorable to their existing point of view.

"It seems counter-intuitive that two individuals would arrive at a more divergent opinion when presented with identical information that is inconclusive, but that's what happens," said David Lee, a doctoral candidate in electrical engineering and a co-author of the paper. "You might think that seeing identical evidence would produce greater moderation and agreement, but it doesn't."

"It seems we look at the world with rose-colored blinders. We see what we want and ignore what doesn't fit," Dandekar said.

Putting the model into practice

The team has studied biased assimilation to help create Internet-based social systems that counteract polarization by what they describe as "surprising validators"—counterbalanced evidence that is presented by otherwise well-known and trusted sources. Imagine Rush Limbaugh or Rachel Maddow taking an unexpected stance. If you were aligned with one or the other, you might be more inclined to listen to the evidence if presented by the source most similar to you on other issues.

"We want to use the insight from our mathematical analysis to create recommendation engines and online collaboration tools to help people find common ground on difficult and divisive societal issues," Lee said.

One such example is Widescope, a budgeting tool built by Goel's research group, in which people take on the role of Congress to allocate the federal budget as they see fit and to compare their budgets against those proposed by various people in Washington—Paul Ryan and President Obama for instance—to see where the differences are.

"What you learn when you see the two budgets side-by-side is just how similar they really are. By articulating the similarities rather than the differences we can focus on collaborating to find a solution," said Goel.

Algorithm in practice

The team used their working model of biased assimilation to also study the polarizing effects of three popular Internet-based recommender systems. Recommender systems are widely used on the Internet to deliver personalized search results, news articles and product suggestions based on the user's likes and dislikes.

It has been claimed that these systems contribute to polarization by compounding the echo chamber effect where, for example, a left-leaning user is recommended more liberal articles and a right-leaning user is recommended more conservative ones.

"The system that recommends the most relevant item to a user turns out to be always polarizing. The other two systems, which chose a random item liked by the user and recommends an item most similar to it, were polarizing only if the user was biased to begin with. It was surprising to find that biased assimilation provides a useful framework to analyze the polarizing effects of recommender systems." Dandekar said.

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User comments : 15

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tadchem
5 / 5 (3) Apr 01, 2013
People are basically lazy thinkers. They tend to accept the first statement they hear on any given topic as near-absolute Truth, and subsequent statements are compared to the first as the Gold Standard. The outcome of this comparison provides the grounds for acceptance or rejection. Thereafter statements that are compatible with the original are accepted as True, and others are less acceptable. Most people carry the politics/religion/beliefs they are exposed to as infant throughout their lives - for better or worse.
Only the most disciplined thinkers are capable of seriously questioning their own axioms honestly and fairly, and of accepting evidence that may cast doubt on the validity of those axioms.
One hundred years later, there are still people who doubt General Relativity and/or Natural Selection despite the preponderance of evidence.
Modernmystic
2.3 / 5 (3) Apr 01, 2013
One hundred years later, there are still people who doubt General Relativity and/or Natural Selection despite the preponderance of evidence.


Not that I doubt natural selection or GR, but isn't your own axiom to continue to question both of those frameworks?
Modernmystic
2.7 / 5 (3) Apr 01, 2013
I actually think people don't change or challenge their beliefs because of fear. This applies to political, personal (relationships of all kinds), and most especially scientific and religious world views.

"The problem usually isn't the problem", the problem in any relationship or conflict of views usually isn't what people are talking about. They aren't addressing the root fears they're harboring. For instance in politics most arguments are about means, not ends. Most conversations are past, not to each other.

Just my two cents.
rwinners
2.6 / 5 (5) Apr 01, 2013
Blame lays at the feet of Ronald Reagan, who did away with the "fairness doctrine"... one of his more nefarious deeds.
bottomlesssoul
3 / 5 (2) Apr 01, 2013
There is no one to blame about biased thinking. In fact, the mere concept of seeking someone or group to blame is a manifestation of bias in the holder of such views.

We are not only all susceptible to it, we are all completely infested with it. Any solution to this if it exists begins with self awareness. After all 90% of alcoholics don't know they are alcoholics. How can you change, if it is even possible, unless you know the feature within you that would be better served if it is changed.
Telekinetic
2.5 / 5 (8) Apr 01, 2013
Man, don't get me started on Reagan, like, how's that "trickle-down" economic theory working out for us? Compliments to all on the observations of misfiring thought neurons, I'll just add this: We aren't taught "analysis" in school even though we're well prepared for it. It's self-taught or lost entirely on too many.
Telekinetic
1 / 5 (2) Apr 01, 2013
There is no one to blame about biased thinking. In fact, the mere concept of seeking someone or group to blame is a manifestation of bias in the holder of such views.

Critical analysis allows us to discern the truth or lack of it in groups that espouse hatred, for instance, where we as a society can then correct aberrant, prejudicial policies.
Macksb
1 / 5 (1) Apr 01, 2013
This issue is well-addressed in math and biological systems, but it appears that the news has not spread to sociology. Art Winfree developed a mathematical law of coupled oscillators circa 1967. He applied it to biology. See Strogatz and Stewart, Coupled Oscillators and Biological Synchronization, Dec 1993, Scientific American. Available online at a math.oregonstate.edu site.

In a two oscillator system (pro-life or pro-choice?), a disorganized group of oscillators will gradually sync in one of two ways: exactly synchronous, or exactly antisynchronous. Homophily or polarization, to borrow the sociological jargon. Probably the most widespread system of self-organization in the universe.
Telekinetic
1 / 5 (3) Apr 01, 2013
Or a third, deleterious effect:

Tesla's electro-mechanical oscillator or earthquake machine is a steam-powered mechanical oscillator invented by Nikola Tesla in 1898. The machine which Tesla tested was small, around seven inches (178 mm) long, and weighing one or two pounds; something "you could put in your overcoat pocket". It was reported that in 1898 Tesla's New York lab was nearly shaken to pieces by this little device, operated by five pounds of air pressure acting against a special pneumatic piston device."
Birger
not rated yet Apr 02, 2013
Human nature is soo unsuited to running a complex civilization. The current mess, with tribalism everywhere, is what you can expect.
A *partial* solution is better education and some kind of news media that actually tells the full, complex story of various issues.
antialias_physorg
not rated yet Apr 02, 2013
We show that repeated averaging of opinions always results in less divergent opinions, even in networks where the people are like-minded," said Pranav Dandekar, a doctoral candidate in MS&E and a co-author on the paper. "You can't create outliers by averaging

Wow. Sociologists need to 'show' this? They must be unaware that there is such a thing as 'math'.
More specifically, people look at inconclusive evidence in a way that is most favorable to their existing point of view

Which doesnt really address the issue how the GOT these views in the first place.

It seems they are missing a piece of the puzzle: Forming opinions based on interpretation of facts WITHOUT any regard for the opinions of others. Even without a social group to compare to people can come to different conclusions based on the same, fuzzy facts (E.g: is it worth playing the lottery or not)
TheGhostofOtto1923
1 / 5 (3) Apr 02, 2013
Or a third, deleterious effect:

Tesla's electro-mechanical oscillator or earthquake machine is a steam-powered mechanical oscillator invented by Nikola Tesla in 1898. The machine which Tesla tested was small, around seven inches (178 mm) long, and weighing one or two pounds; something "you could put in your overcoat pocket"
Was this thing phallus-shaped?
A *partial* solution is better education and some kind of news media that actually tells the full, complex story of various issues
The enduring Solution has been to divide the people up and set them against one another in Controlled and Productive ways. The best iteration of this Process so far has been democracy and its evil twin, capitalism.

This enables Progress by increasing consumption, while allowing for reduced pop growth without war. Pretty ingenious.
TheGhostofOtto1923
1 / 5 (3) Apr 02, 2013
And as always the only education the people ever need, is the one which facilitates this.

Leaders reached the conclusion long long ago that the people were the sole enemies of rulers everywhere.

Prosperity fuels overgrowth, and the people will always blame their rulers for their ensuing misery, no matter how benevolent and attentive these rulers might be.

And so in order to preserve civilization, rulers decided to make war on the people by compelling them to fight one another Constructively. This can obviously be very easy when you assume that Leaders of apparently opposing factions, are actually on the same Side, and working toward the same Goals.

Leaders who can predetermine the results of conflicts can reap unimaginable Benefits; but the greatest of all is a future of assured Prosperity for They and Their descendants.

A Tribe of Leaders owns this world and has pledged to protect it from the tropical apes who would consume it. Hail Empire.
TheGhostofOtto1923
1 / 5 (3) Apr 02, 2013
"16 For God so loved the WORLD that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life." john3

-Translation: 'In order to protect the WORLD from the people upon it, Leaders are willing to promise them absolutely ANYTHING, up to and including everlasting life in heaven.'

This, the greatest of all gifts and the one Leaders will absolutely never have to deliver on. They only need to be able to offer it with sufficient authority and credibility.

And this is in reality not all that difficult to do, as immortality is something that the people want more than anything in the world, and will do almost anything to get. And so they are not all that concerned about evidence.

The POWER of this promise is so great that it HAS to be offered to the people, or some other entity will do so instead. Like any weapon, it has to be developed first or your enemies will inevitably do so and use it to destroy you.

Religion - Empires most formidable Weapon.
TheGhostofOtto1923
1 / 5 (3) Apr 02, 2013
"America has grown more polarized in recent years. What's not so certain is why."

-And so Ive just told you WHY. I want money for this.