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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
MichaelMathioudakis 4
5
noinformationbarriers
citizenjournalism
socialconnectivity
…
…
harassment
fakenews
polarization
socialmedia:goodandbadsides
MichaelMathioudakis
polarization
political orsocialpolarization‘theactofseparatingormakingpeopleseparateinto
twogroupswithcompletelyoppositeopinions’*
relatedterm:controversy‘publicdiscussionandargumentaboutsomethingthat
manypeoplestronglydisagreeabout’*
*oxfordenglish dictionary
MichaelMathioudakis 6
whystudypolarization?
polarizationcanbelinkedtoadverseeffects
socialsegmentationstereotypes
echochambers
goalunderstandandmitigate them
MichaelMathioudakis 7
8
0102030405060708090100
DonaldTrumpApprovalRating%February2017
Democrats Republicans
MichaelMathioudakis
9
ideologyofUSApublicsource:PewResearchCenter
1994
2014
DemocratsandRepublicanshavedriftedapart
MichaelMathioudakis
whystudypolarizationonsocialmedia
extractinsightsonthepolarizationprocess
somespecificquestionswhatarethepolarizingissues?
doespolarizationincreaseovertime?wesawonesuchinstance:USpublic
howcouldwe‘nudge’peopleawayfromextremepolarization?
ispolarizationlinkedtoechochambers?dosocialmediaincreasepolarization?
MichaelMathioudakis 10
this
talk
inthistalk…
algorithmstomeasureit
long-termstudy
nextsteps
11
polarization
MichaelMathioudakis
microbloggingplatformsince2006;300millionactiveusers
userspostshortmessages- ‘tweets’
12MichaelMathioudakis
13
retweetstweet
replies
connections
interactionsMichaelMathioudakis
globalstructureofinteractions
nodes
14
useraccounts
edges retweetsrepliesconnections
interactiongraph
MichaelMathioudakis
1%sampleofalltweetsfromtheinternetarchive
data
inwhatfollows…
15MichaelMathioudakis
twitteralgorithmstomeasureit
long-termstudynextsteps
polarization
QuantifyingControversyinSocialMedia. WSDM2016.WithKiranGarimella,Gianmarco DeFrancisci Morales,AristidesGionis.
howpolarizedisadiscussion?
e.g.,obamacare inJanuary2017
16MichaelMathioudakis
howcouldweapproachthisquestion?
content?doopposingsidessaydifferentthings?
sentiment?dopolarizedtopicsexhibitwider
rangeofemotions?
interactions?dopeopleinteractmorewiththeirownside?
MichaelMathioudakis 17
let’strythis
methodtemplate
buildaninteractiongraphseveraltypestotry
retweets,replies,connections
istheinteraction graph polarized?
output:polarizationscore
18
notpolarized polarizedtwosides,wellseparated
MichaelMathioudakis
pipeline
19MichaelMathioudakis
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?
21
partitionintotwosides
MichaelMathioudakis
topic
evaluatio
n
Graph Building
Graph Partitioning
Controversy Measure
Polarization
whattypeofinteractiongraphshouldweuse?
howtofindtwosidesinthe
graph?
howtomeasuretheseparationbetween
twosides?
doweidentifypolarized
discussions?
partitioning
manyexistingalgorithms
spectralclusteringlabelpropagationmetis
MichaelMathioudakis 22
wellconnected
badlyconnected
randomwalkcontroversy(RWC)
23MichaelMathioudakis
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)
26
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
29MichaelMathioudakis
populartopicsof2015graphswith1– 150thousandnodes
examples:
Graph Building
Graph Partitioning
Controversy Measure
Polarization
results
MichaelMathioudakis 30
doesthepipelinedistinguishpolarizedfromnon-polarizedtopics?
retweetsreplies
connections
twosides randomwalkcontroversy(RWC)
topic
(ifweuseretweets)yes!
results
nemtsovprotests
indianbeefban
sxswconference
germanwingsplanecrash
interactiongraphs:retweets31MichaelMathioudakis
polarized
topics
non-polarizedtopicshighRWC lowRWC
results
32
retweets replies
interactiongraphsfornemtsov protests
MichaelMathioudakis
analgorithmicwaytoquantifypolarization
MichaelMathioudakis 33
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
MichaelMathioudakis 36
RWCvsTime
37MichaelMathioudakis
September2011
September2016
volumeofactivityspikesatmajorevents
38MichaelMathioudakis
39MichaelMathioudakis
doespolarizationspikewithvolume?measurerwc vsvolumeofactivity
40MichaelMathioudakis
RWCvsVolume
highervolume
higherco
ntroversy
41MichaelMathioudakis
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