measuring polarization on social media
TRANSCRIPT
measuringpolarizationonsocialmediamichael mathioudakis
computerscienceaalto university
http://www.michalis.co
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socialmedia
MichaelMathioudakis
consumecontentnewsaboutfriends,politics,favoriteartists
generatecontentshareexperiences,interestingarticles
interactwithotherscomment,rate,anddiscuss
hundredsofmillionsofactiveusers
whystudysocialmedia
awindowintothethoughtsandactionsofpeople
howpeoplespendtheirtimewhatattractstheirattention
whattheythinkaboutpoliticalissueshowtheyinteractsocially
uniqueopportunityforsocialscientistsstudyhumanbehavior
atlargescale&finedetail
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butyouareacomputerscientistdevelopalgorithmsto
extractinsightsfromsocialmedia
twochallenges1- volumeofdata
2- complexityofsocialbehaviorcallsforcomplexmodels (e.g.,graphs)
thatrequirefastalgorithms
solutionalgorithmicmethods,softwaretools andsystems
forlarge-scalecomputationanalyze efficiently&automatically largeamountsofdata
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noinformationbarriers
citizenjournalism
socialconnectivity
…
…
harassment
fakenews
polarization
socialmedia:goodandbadsides
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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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0102030405060708090100
DonaldTrumpApprovalRating%February2017
Democrats Republicans
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ideologyofUSApublicsource:PewResearchCenter
1994
2014
DemocratsandRepublicanshavedriftedapart
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whystudypolarizationonsocialmedia
extractinsightsonthepolarizationprocess
somespecificquestionswhatarethepolarizingissues?
doespolarizationincreaseovertime?wesawonesuchinstance:USpublic
howcouldwe‘nudge’peopleawayfromextremepolarization?
ispolarizationlinkedtoechochambers?dosocialmediaincreasepolarization?
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this
talk
inthistalk…
algorithmstomeasureit
long-termstudy
nextsteps
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polarization
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microbloggingplatformsince2006;300millionactiveusers
userspostshortmessages- ‘tweets’
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globalstructureofinteractions
nodes
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useraccounts
edges retweetsrepliesconnections
interactiongraph
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1%sampleofalltweetsfromtheinternetarchive
data
inwhatfollows…
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twitteralgorithmstomeasureit
long-termstudynextsteps
polarization
QuantifyingControversyinSocialMedia. WSDM2016.WithKiranGarimella,Gianmarco DeFrancisci Morales,AristidesGionis.
howcouldweapproachthisquestion?
content?doopposingsidessaydifferentthings?
sentiment?dopolarizedtopicsexhibitwider
rangeofemotions?
interactions?dopeopleinteractmorewiththeirownside?
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let’strythis
methodtemplate
buildaninteractiongraphseveraltypestotry
retweets,replies,connections
istheinteraction graph polarized?
output:polarizationscore
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notpolarized polarizedtwosides,wellseparated
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pipeline
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topic
evaluatio
n
Graph Building
Graph Partitioning
Controversy Measure
Polarization
whattypeofinteractiongraphshouldweuse?
howtofindtwosidesinthe
graph?
howtomeasuretheseparationbetween
twosides?
doweidentifypolarized
discussions?
retweetsreplies
connections
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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
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A andB:twosides
c andd:centralnodes
andvalues-1to1
themoredifficultthehigherthescorehowdifficulttoreachdfromA
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cd
A B
randomwalk
randomwalk
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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
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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
analgorithmicwaytoquantifypolarization
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retweets twosides randomwalkcontroversy(RWC)
topic
basedonstructureofinteractionslanguage-independent
Graph Building
Graph Partitioning
Controversy Measure
Polarization
newmethodcanbedeployedinthewild
inwhatfollows…
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twitteralgorithmstomeasureit
long-termstudynextsteps
polarization
Graph Building
Graph Partitioning
Controversy Measure
TheEbbandFlowofControversialDebatesonSocialMedia.ICWSM2017.TheEffectofCollectiveAttentiononControversialDebatesonSocialMedia.WebScience 2017.WithKiranGarimella,Gianmarco DeFrancisci Morales,AristidesGionis.
Polarization
polarizationovertime
haspolarizationaroundcontroversialtopicsincreasedovertime?
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polarizationovertime
data1%sampleofalltweetsfromtheinternetarchive
September2011toSeptember2016
methodforagiventopic(e.g.,obamacare)
retrieverelatedtweetsbuildaninteractiongraphforeachday
usingretweetsmeasureRWCscore
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whystudypolarizationonsocialmedia
extractinsightsonthepolarizationprocess
somespecificquestionswhatarethepolarizingissues?
doespolarizationincreaseovertime?wesawonesuchinstance:USpublic
howcouldwe‘nudge’peopleawayfromextremepolarization?
ispolarizationlinkedtoechochambers?dosocialmediaincreasepolarization?
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this
talk
nextsteps