false consensus on Facebook

Political scientists have known for a while that we're not so good at knowing our friends' political views; we, instead, tend to just think our friends agree with us much more than they actually do.

Why that's the case is a bit of a mystery. One theory is that we hide disagreement from our friends (or even lie a little about our beliefs) when we're in mixed company (especially when we're in the minority) - so it's only natural that when we disagree with our friends they wouldn't know it. Another explanation is that, regardless of how much information or disinformation we have about our friends, we all suffer from "false consensus bias," the tendency to think that others think like us.

Sharad Goel, Winter Mason and Duncan Watts try to pick apart what may be behind our misperceptions in 2010 paper that surveys Facebook friends, but I'm not sure they solve the mystery. (Although I do have a cold so maybe I'm too foggy to see it.)

They do, however, have tons of cool observations and insights. 

After looking at 900 pairs of friends, first off, they find that - as we'd expect - friends agree with each other about 75% of the time, which is 12 percentage points higher than random (since you'd expect a random pair in their sample to agree 63% of the time. They also find - again no surprises - that friends tend to overestimate how much they agree with their friends.

Things get interesting when the authors look at differences in those overestimations. They find two things. One, the more we actually disagree with our friends, the more we overestimate how much we agree. Two, the 'closer' we are to friends (ie the more friends we have in common), the less we overestimate our agreement.

The authors puzzle over why we might see those differences: is it because we actually know more about our close friends? Do we likewise share more information with those who we agree with, so we have a better sense of what they believe?

The puzzle, though, might be solved with two assumptions - one of which the authors point out, the other which they miss (although I may have missed their discussion of it). When it comes to overestimating our agreement with those we disagree with, we might just be dealing with a ceiling effect; if agree with someone on 90% of political issues, I can only overestimate our agreement by 10 percentage points, but with someone I agree with 60% of the time there's lots of room for overestimation. 

The other explanation is one the authors point to as well: this could all be about false consensus. The authors find that when we agree in reality, we know it 90% of the time (that is, only 10% of the time do we get it wrong and think we disagree). But when we disagree with someone, we only know it 40% off the time! What that means is that if we consistently guess agreement correctly 90% of the time and disagreement 40% of the time, we're going to "correctly" guess agreement with those we agree with more often.

The shape of virality

Tweets rarely go viral. Again, as Goel et al tell us in the paper I blogged about yesterday, almost all tweets we see are either one shot posts (95%) or first round retweets (3%). But that means 2% are viral-ish, being retweeted at least twice down the chain.

But what do those viral cascades look like? Are they like the spread of the flu, slowly working their way from person to person, infecting a few at at time but eventually hitting large swathes of the population? Or do they spread in bursts, propelled by super-tweeters? And is there something about the inherent tweet-worthiness of a post that makes it more likely to go viral?

Goel takes on these questions, again with Duncan Watts (and adding on Ashton Anderson and Jake Hofman), in an extremely impressive paper that tracks over a billion tweets and simulates diffusion on model networks with 25 million nodes. (Woah.)

First, they find that what we might call tweet cascades are even rarer than stated above. If you consider cascades that have at least 100 retweets, those make up only 0.025% of all initial tweets. (What's less clear is what percent of tweets we see on our wall are initial tweets or retweets. The fact that the authors track 600 million initial tweets and a total of 1.2 billion "adoptions" suggests that half of the tweets we see are re-tweets.)

When they do go viral, to get back to the questions above, they don't look like flu epidemics or like broadcasts - rather a mash of both kinds of cascades. Since pictures will save me using a thousand words:

The images are in order of their "structural virality" - the most "virally" cascade being in the bottom right corner - but all of them show a combination of both central tweeters broadcasting a tweet and lots of little tweeters passing it along.

A more interesting finding, though, is that there doesn't have to be anything particularly "sticky" about a tweet to see super cascades like the ones above. The authors do some impressive modeling on "scale free" networks (ones that look like Twitter) and find that even if you choose a fixed "stickiness" of tweets (ie the probability that they'll be retweeted) you'll find a similar array of cascades running simulations on those models as you find in reality on Twitter. In other words, whether a tweet turns out to be a dud or be a super-virus could just be a function of randomness. Cool stuff.

Viral social media stories?

When we think of the many ways social media has transformed our information worlds, one specter that comes to mind is that of the viral story - a news event that may be ignored by the lame-stream, but that seeps its way into Twitter or FB, slowly catches on (or flares immediately) and eventually saturates our online social networks.

But, while those events may or may not exist, they are probably exceedingly rare, according to a 2012 paper by Sharad Goel, Duncan Watts and Daniel Goldstein. Those researchers tracked 80,000 Twitter stories to see what the typical "cascade" (wave of retweets started by a single tweet) looked like. Perhaps unsurprisingly, 95% of cascades can't really be called such - they are made up of a single tweet that never gets retweeted. 

But, the authors ask, even though most cascades never really happen, might there be enough huge cascades that they end up making up most (or much) of our social media news-stream. Not so. When we do retweet news stories we do so from the source; 60% of retweets aren't branching off from long information cascades, but are simply retweeting the story from its origin.

Of the 80,000 stories the researchers tracked, only about 0.001% make it out past 5 waves of retweets, suggesting that viral news stories are - if anything - extremely rare. The authors suggest instead that what may seem like viral social media stories may, in fact, be spread by the traditional media - and that they saturate our social media walls because everyone is picking up the story from, say, CNN or the Washington Post.

It could be, though, that the researchers' sample was too small to pick up the "mega-cascades" that we imagine are a unique feature of social media. The "Trayvon Martin" stories, which circulate for weeks on social media before being picked up by traditional media may be, truly, 1 in a million - or billion - rather than 1 in 80,000.

Still, the authors' findings make it hard to deny that the vast majority of news stories we see on Twitter are either initial tweets or one-off retweets - and that super cascades are the tiniest sliver of the news we see. Of the stories swirling around social media, almost all are stories users find from outside Twitter and bring into the network for a single exposure. It's show and tell rather than a game of telephone.

That would mean that what really matters for determining what we see in social media is not what people re-post, but rather what they find from the outside media and decide is important enough to post themselves.

open-minded conservatives?

I'm not 100% sure what to make of it, but - according to research from Matthew Gentzkow and Jesse Shapiro - it looks like conservatives spend a lot more time hanging around liberal websites than liberals do on conservative sites.

Here's Gentzkow and Shapiro's breakdown of who visits the ten top conservative and liberal sites:

Conservative sites visitors

Liberal sites visitors

Assuming we trust their data, one explanation for the imbalance could simply be that there are tons more conservatives visiting all political sites; if that were the case, even if liberals and conservatives had similar biases toward consuming like-minded media, we'd still see more conservatives on liberal sites. But my guess is there aren't that many more conservatives lurking online.

Another possible explanation is that - as suggested in the title - conservatives are more open-minded than liberals. Either that or they are more willing to check out what the opposition is saying. That story is somewhat plausible; other research suggests that savvy ideologues are more inclined (than less informed ideologues) to click on "counter-attitudinal" articles because they're more comfortable debunking any opposing views they may happen to bump into.

Still, it's curious why you'd see so many more conservative ideologues venturing into liberal waters than vice versa. The final explanation I can come up with - and one that suits my lefty leanings - is that "liberal sites" aren't as liberal as "conservative sites" are conservative; that is, that a conservative visiting DailyKos is more likely to come across information he can jive with than a liberal is going to find on RushLimbaugh. In other words, liberal websites - as opposed to conservatives readers - are the ones who are open-minded.

Any other interpretations out there?

a note on Robin Williams and suicide

I am sad at Robin William's passing, but only sad for myself - not for Robin Williams. 

If I may, I suggest others not be sad for him either. To be so would be to assume that his last moments were filled with despair, confusion and a powerlessness to choose life. That might be an apt assumption to make for a sixteen year old who has been bullied and does not have the perspective to know that "it will get better," but not for a 63 year old artistic genius who has, very likely, lived a life far richer and deeper - in experience, emotion and wisdom - than I, at least, can hope for. His last moments may have been confused and despairing or they may have had a clarity of thought and welling of spirit that is beyond my understanding. I don't know. 

I do suspect, however, that we have a bias against suicide - that we see it as uniformly negative. While there are many reasons that is a good bias to have (not least, for perpetuating the species), I leave open the possibility that sometimes the choice of death is not something to feel sad about - but to respect, honor and maybe even admire.

Facebook polis

If you have a Facebook account which you visited even once in early August, you could not have missed it; Facebook walls normally filled with food photos, vacation Instagrams and Buzzfeed links, now overrun by posts condemning either Israel or Hamas, lamenting the fate of those in Gaza or defending the actions of Israel. The media noted the phenomenon, as did more than one of my Facebook connections, some who admitted to "defriending" friends over the online conflict.

While many saw the explosion of the Israeli-Palestinian conflict on Facebook walls as an unfortunate violation of social media norms, this political scientist - and perhaps others like me who advocate for more citizen engagement - was heartened. Yes, I'm sure many of the posts "crossed lines" and it is never a good thing to lose a friend (over something like politics), but when you live in a society where people disagree strongly over important issues, nothing is better for democracy than a healthy debate.

That last statement is, of course, debatable. Those who study citizen deliberation - as will be unsurprising to anyone who's ever had a political discussion themselves - note that there are many potential downsides to "cross-cutting" dialogue. Instead of leading to better understanding, people engaged in political debate may just become more entrenched in their views. That's because we all share a pair of biases - confirmation and disconfirmation - which incline us to zero in on information that supports our views and swiftly discount information that challenges thems. More worrisome is the risk that comes when "lines are crossed" - that is, when debate becomes uglified by off-color comments, ad hominem attacks or other forms of nastiness. That's when friends get lost and, worse, people become convinced that those who disagree with them not only see the world differently but are some shade of "bad people."

But even though debate comes with considerable risks, we starry-eyed (small d) democrats have got to believe that the risks are outweighed by the benefits. For one, when we're silent about our views we have no chance of exposing others to different perspectives (and being exposed ourselves). (This is especially true today as we can become increasingly selective in our media choices.) While ignorance is arguably bliss on most topics, it can be dangerous when important issues are on the line. And even if we don't gain greater understanding of an issue through debate with our friends, there is a good chance that we'll appreciate other perspectives just by virtue of our friends holding them. This is the great hope of dialogue - that, at least when individuals share their views civilly (ie, avoiding nastiness), it's hard for rifts not to be somewhat narrowed (if rarely totally mended).

Whether the current Gaza-Israel Facebook battle results in a widening or narrowing of the divide between both sides - that is, whether the forces of repulsion or attraction win out in this case - is a matter of guess work. But maybe in some future of data-analysis wizardry we can test to see.

research finds

... from a trawl through 2013 research papers posted by Kevin Lewis:

• Messing with people's default categories of groups can promote tolerance.
• Having a sense of the meaning of life only helps you if it's stable over time.
• Explaining the decrease in human violence - since the dawn of history.
• Iraq and Afghanistan aren't the exceptions: forcing democracy rarely works.
• The price of voting, according to some economists, is about $10-$15. (Stefano Dellavigna et al)
• When politicians agree, it's not necessarily good for us. (Keena Lipsitz)
• One of the reasons citizens don't bother to vote may be because they know their representatives can't do much. (Ryan Carlin)
• An increasingly polarized media may be polarizing the most politically involved, but not the rest of us. (Markus Prior)
• ... And that may be because most of us tune out the polarized media. (Kevin Arcenaux et al)