measuringpolarizationonsocialmediamichael mathioudakis

computerscienceaalto university

http://www.michalis.co

2

socialmedia

MichaelMathioudakis

consumecontentnewsaboutfriends,politics,favoriteartists

generatecontentshareexperiences,interestingarticles

interactwithotherscomment,rate,anddiscuss

hundredsofmillionsofactiveusers

whystudysocialmedia

awindowintothethoughtsandactionsofpeople

howpeoplespendtheirtimewhatattractstheirattention

whattheythinkaboutpoliticalissueshowtheyinteractsocially

uniqueopportunityforsocialscientistsstudyhumanbehavior

atlargescale&finedetail

MichaelMathioudakis 3

butyouareacomputerscientistdevelopalgorithmsto

extractinsightsfromsocialmedia

twochallenges1- volumeofdata

2- complexityofsocialbehaviorcallsforcomplexmodels (e.g.,graphs)

thatrequirefastalgorithms

solutionalgorithmicmethods,softwaretools andsystems

forlarge-scalecomputationanalyze efficiently&automatically largeamountsofdata

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5

noinformationbarriers

citizenjournalism

socialconnectivity

…

…

harassment

fakenews

polarization

socialmedia:goodandbadsides

MichaelMathioudakis

polarization

political orsocialpolarization‘theactofseparatingormakingpeopleseparateinto

twogroupswithcompletelyoppositeopinions’*

relatedterm:controversy‘publicdiscussionandargumentaboutsomethingthat

manypeoplestronglydisagreeabout’*

*oxfordenglish dictionary

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whystudypolarization?

polarizationcanbelinkedtoadverseeffects

socialsegmentationstereotypes

echochambers

goalunderstandandmitigate them

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8

0102030405060708090100

DonaldTrumpApprovalRating%February2017

Democrats Republicans

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ideologyofUSApublicsource:PewResearchCenter

1994

2014

DemocratsandRepublicanshavedriftedapart

MichaelMathioudakis

whystudypolarizationonsocialmedia

extractinsightsonthepolarizationprocess

somespecificquestionswhatarethepolarizingissues?

doespolarizationincreaseovertime?wesawonesuchinstance:USpublic

howcouldwe‘nudge’peopleawayfromextremepolarization?

ispolarizationlinkedtoechochambers?dosocialmediaincreasepolarization?

MichaelMathioudakis 10

this

talk

inthistalk…

twitter

algorithmstomeasureit

long-termstudy

nextsteps

11

polarization

MichaelMathioudakis

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retweetstweet

replies

connections

interactionsMichaelMathioudakis

twitter

microbloggingplatformsince2006;300millionactiveusers

userspostshortmessages- ‘tweets’

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globalstructureofinteractions

nodes

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useraccounts

edges retweetsrepliesconnections

interactiongraph

MichaelMathioudakis

1%sampleofalltweetsfromtheinternetarchive

data

inwhatfollows…

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twitteralgorithmstomeasureit

long-termstudynextsteps

polarization

QuantifyingControversyinSocialMedia. WSDM2016.WithKiranGarimella,Gianmarco DeFrancisci Morales,AristidesGionis.

howpolarizedisadiscussion?

e.g.,obamacare inJanuary2017

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howcouldweapproachthisquestion?

content?doopposingsidessaydifferentthings?

sentiment?dopolarizedtopicsexhibitwider

rangeofemotions?

interactions?dopeopleinteractmorewiththeirownside?

MichaelMathioudakis 17

let’strythis

methodtemplate

buildaninteractiongraphseveraltypestotry

retweets,replies,connections

istheinteraction graph polarized?

output:polarizationscore

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notpolarized polarizedtwosides,wellseparated

MichaelMathioudakis

pipeline

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topic

evaluatio

n

Graph Building

Graph Partitioning

Controversy Measure

Polarization

whattypeofinteractiongraphshouldweuse?

howtofindtwosidesinthe

graph?

howtomeasuretheseparationbetween

twosides?

doweidentifypolarized

discussions?

retweetsreplies

connections

20MichaelMathioudakis

topic

evaluatio

n

Graph Building

Graph Partitioning

Controversy Measure

Polarization

whattypeofinteractiongraphshouldweuse?

howtofindtwosidesinthe

graph?

howtomeasuretheseparationbetween

twosides?

doweidentifypolarized

discussions?

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partitionintotwosides

MichaelMathioudakis

topic

evaluatio

n

Graph Building

Graph Partitioning

Controversy Measure

Polarization

whattypeofinteractiongraphshouldweuse?

howtofindtwosidesinthe

graph?

howtomeasuretheseparationbetween

twosides?

doweidentifypolarized

discussions?

partitioning

manyexistingalgorithms

spectralclusteringlabelpropagationmetis

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wellconnected

badlyconnected

randomwalkcontroversy(RWC)

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topic

evaluatio

n

Graph Building

Graph Partitioning

Controversy Measure

Polarization

whattypeofinteractiongraphshouldweuse?

howtofindtwosidesinthe

graph?

howtomeasuretheseparationbetween

twosides?

doweidentifypolarized

discussions?

randomwalkcontroversy(RWC)

polarizationscorehowdifficulttoreachc fromB

24

A andB:twosides

c andd:centralnodes

andvalues-1to1

themoredifficultthehigherthescorehowdifficulttoreachdfromA

MichaelMathioudakis

cd

A B

randomwalk

randomwalk

25MichaelMathioudakis

discreteprocess onagraphstep1,2,3,…

ateachstep,weareatonenodeatnextstep,wemovetoanearbynode

- followinganedge atrandom

specifywherethewalkstarts (e.g.,atc)wherethewalkends (e.g.,atd)

cd

randomwalkcontroversy(RWC)

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A andB:twosides

c andd:centralnodes

MichaelMathioudakis

cd

A B

randomwalkstart:randomnodeofA/B50%chancethatwedoeitherend:atcentralnodescofsideA ordofsideB

PXY =P(startedinX |endedinY)

considertwoindependentinstancesoneending atthecentralnodeofsideA,theotheratthecentralnodeofsideB

RWC=PAAPBB - PBAPAB

bothrandomwalksstartedinthesidewheretheyended

bothrandomwalksstartedinasideotherthanwheretheyended

values?

randomwalkcontroversy(RWC)

27MichaelMathioudakis

topic

evaluatio

n

Graph Building

Graph Partitioning

Controversy Measure

Polarization

whattypeofinteractiongraphshouldweuse?

howtofindtwosidesinthe

graph?

howtomeasuretheseparationbetween

twosides?

doweidentifypolarized

discussions?

28MichaelMathioudakis

topic

evaluatio

n

Graph Building

Graph Partitioning

Controversy Measure

Polarization

whattypeofinteractiongraphshouldweuse?

howtofindtwosidesinthe

graph?

howtomeasuretheseparationbetween

twosides?

doweidentifypolarized

discussions?

evaluation

non-polarized topics

indian beefban,nemtsov protests,netanyahu UScongressspeech,

baltimore riots,ukrainepolarizedtopics

germanwings planecrash,sxsw,mother’sday,jurassic worldmovie,

nationalkissingday

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populartopicsof2015graphswith1– 150thousandnodes

examples:

Graph Building

Graph Partitioning

Controversy Measure

Polarization

results

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doesthepipelinedistinguishpolarizedfromnon-polarizedtopics?

retweetsreplies

connections

twosides randomwalkcontroversy(RWC)

topic

(ifweuseretweets)yes!

results

nemtsovprotests

indianbeefban

sxswconference

germanwingsplanecrash

interactiongraphs:retweets31MichaelMathioudakis

polarized

topics

non-polarizedtopicshighRWC lowRWC

results

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retweets replies

interactiongraphsfornemtsov protests

MichaelMathioudakis

analgorithmicwaytoquantifypolarization

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retweets twosides randomwalkcontroversy(RWC)

topic

basedonstructureofinteractionslanguage-independent

Graph Building

Graph Partitioning

Controversy Measure

Polarization

newmethodcanbedeployedinthewild

inwhatfollows…

34MichaelMathioudakis

twitteralgorithmstomeasureit

long-termstudynextsteps

polarization

Graph Building

Graph Partitioning

Controversy Measure

TheEbbandFlowofControversialDebatesonSocialMedia.ICWSM2017.TheEffectofCollectiveAttentiononControversialDebatesonSocialMedia.WebScience 2017.WithKiranGarimella,Gianmarco DeFrancisci Morales,AristidesGionis.

Polarization

polarizationovertime

haspolarizationaroundcontroversialtopicsincreasedovertime?

35MichaelMathioudakis

polarizationovertime

data1%sampleofalltweetsfromtheinternetarchive

September2011toSeptember2016

methodforagiventopic(e.g.,obamacare)

retrieverelatedtweetsbuildaninteractiongraphforeachday

usingretweetsmeasureRWCscore

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RWCvsTime

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September2011

September2016

volumeofactivityspikesatmajorevents

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doespolarizationspikewithvolume?measurerwc vsvolumeofactivity

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RWCvsVolume

highervolume

higherco

ntroversy

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highervolume highervolume

RWCvsVolume

MichaelMathioudakis 42

highervolume

higherco

ntroversy

rwc

summary

43MichaelMathioudakis

twitteralgorithmstomeasureit

long-termstudynextsteps

polarization

whystudypolarizationonsocialmedia

extractinsightsonthepolarizationprocess

somespecificquestionswhatarethepolarizingissues?

doespolarizationincreaseovertime?wesawonesuchinstance:USpublic

howcouldwe‘nudge’peopleawayfromextremepolarization?

ispolarizationlinkedtoechochambers?dosocialmediaincreasepolarization?

MichaelMathioudakis 44

this

talk

nextsteps

thank you!

45MichaelMathioudakis