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ウェブ・ソーシャルメディア論文読み会: How digital media drive affective polarization through partisan sorting
ウェブ・ソーシャルメディア論文読み会第2回で発表したものです。
taichi_murayama
February 16, 2023
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How digital media drive affective polarization through partisan sorting (PNAS
2022) ଜࢁଠҰ େࡕେֶ ウェブ・ソーシャルメディア論⽂読み会 第2回 -
2 ֓ཁ How digital media drive affective polarization through partisan
sorting (PNAS 2022) Peter Törnberg (Unveristy of Amsterdam) l Proceedings of the National Academy of Sciencesͱ͍͏༗໊δϟʔφϧ͔Βग़൛͞Εͨจ l Peter TörnbergࢯʹΑΔ୯ஶ l ΞϜεςϧμϜେֶॴଐɻ l ෳࡶܥίϯϐϡʔλʔαΠΤϯεΛ༻͍ͨɺཧۭؒʹ͓͚ΔۃԽϑΣΠΫχϡʔεͷੳʹैࣄ l 1-P4 POFl&DIPDIBNCFSTBOEWJSBMNJTJOGPSNBUJPO.PEFMJOHGBLFOFXTBTDPNQMFY DPOUBHJPOzͳͲ͕༗໊ l ͲΜͳจʁ ιʔγϟϧϝσΟΞͳͲͰݟΒΕΔۃԽ͕ରҙݟʹ৮Εͳ͍͜ͱʹΑΔΤίʔνΣϯόʔʹΑͬͯੜ͡Δͷ Ͱͳ͘ɺΉ͠ΖɺιʔγϟϧϝσΟΞʹΑͬͯ֎ͷਓʑͱަྲྀ͢ΔΑ͏ʹͳΓ֤Ҭʹ͓͍ͯଘࡏͨ͠ଟ༷ੑ͕ ୯७ͳೋۃͱz4PSUJOHz ͞ΕΔ͜ͱΛΦϐχΦϯμΠφϛοΫεͱ͍͏ख๏Λ༻͍ͯݕূ -
3 ४උ エコーチェンバー from: Cossard, Alessandro, et al. "Falling into
the echo chamber: the Italian vaccination debate on Twitter." Proceedings of the International AAAI conference on web and social media. Vol. 14. 2020. from: Wikipeida l ൃ৴͞ΕͨϝοηʔδΛ֦େ͠ɺ͕དྷͳ͘ͳΔՄೳੑΛ࣋ͭࣅͨͷಉ࢜Ͱܨ͕ͬͨด ͟͞Εۭͨؒͷ͜ͱ l ରཱ͢ΔϢʔβάϧʔϓͷҙݟ͔Βݽཱ͢ΔΤίʔνΣϯόʔೋۃԽͷओͳཁҼʢͱߟ ͑ΒΕͯΔʣ l ภͬͨใҰ෦ͷάϧʔϓͰϑΣΠΫχϡʔε͔ΓྲྀΕΔͳͲѱӨڹ -
6 地域A 地域B Partisan Sorting 猫 vs. ⽝ ご飯 vs.
パン 交流 全国 猫派 & 朝⾷はご飯 ⽝派 & 朝⾷はパン ४උ -
7 エコーチェンバーによって分極化が⽣じていることへ疑問 ४උ l ରҙݟͷίϯςϯπΛڞ༗͠ͳ͍͕ɺରҙݟʹ;ΕΔ PSԠ͢Δ͜ͱසൟʹੜ͡Δ l ΞϝϦΧɺΠεϥΤϧ྆ࠃʹ͓͍ͯҟͳΔҙݟͷχϡʔεΛආ͚͓ͯΒͣɺ৮ΕΔ͜ͱͰ͔͑ͬͯภ ޫΛڧΊΔ͜ͱΛࣔࠦ ・Implications
of pro-and counter attitudinal information exposure for affective polarization., Hum. Commun. Res., (2014). ・Exposure to opposing views on social media can increase political polarization. Proc. Natl. Acad. Sci., (2018). ・Tweeting from left to right: Is online political communication more than an echo chamber? Psychol. Sci. 26, 1531–1542 (2015). ・Of echo chambers and contrarian clubs: Exposure to political disagreement among German and Italian users of Twitter. Soc. Media Soc. 2, 1–24 (2016). -
8 Partisan Sortingが⽣じている可能性 ४උ l σδλϧϝσΟΞަྲྀΛଅ࣏͠తͳݴ͍૪͍ʹר͖ࠐΉ͜ͱͰɺͲͪΒͷཱʹཱ͖͔ͭΛٻ ΊΔޮՌΛ࣋ͭ ಛʹ࠷ۙͷΞϝϦΧ l ΞϝϦΧͷେౘ࣏తͳͷ͚ͩͰͳ͘ɺফඅߦಈݸਓͷಓಙ·Ͱٵऩ͠zDVMUVSFXBSzΛ
Ҿ͖ى͍ͯ͜͠Δ "GGFDUJWF1PMBSJ[BUJPOͱͷؔ࿈ l ଟ༷ͳࣾձΞΠσϯςΟςΟΛΧόʔ͠ɺͭͷΞΠσϯςΟςΟʹׂ͢Δͱ͍͏ΞϝϦΧࣾձͷ࠷ ۙͷ ・ L. Mason, Uncivil Agreement: How Politics Became Our Identity (University of Chicago Press, 2018). ・ N. McCarty, K. T. Poole, H. Rosenthal, Polarized America: The Dance of Ideology and Unequal Riches (MIT Press, 2016). ・A. Guess, B. Nyhan, B. Lyons, J. Reifler, Avoiding the echo chamber about echo chambers. Knight Foundation 2, 1–25 (2018). ・ M. Hetherington, J. Weiler, Prius Or Pickup?: How the Answers to Four Simple Questions Explain America’s Great Divide (Houghton Mifflin, 2018). -
9 本研究の⽬的 ४උ l ιʔγϟϧϝσΟΞͷ಄ʹΑͬͯ1BSUJTPO4PSUJOH͕ੜͯͦ͡͏ͳͷ͔͕ͬͨɺͲͷΑ͏ͳ ΈͰੜ͍ͯ͡Δͷ͔͔͍ͬͯͳ͍ l ͲͷΑ͏ʹݸਓͷҙݟมԽ͠ɺͲͷΑ͏ʹࣾձऩଋ͍ͯ͘͠ͷ͔ʁͦΕΛઆ໌͢ΔΑ͏ͳϞσϧ ͕ະͩଘࡏ͠ͳ͍ 1BSUJTPO
4PSJUOHͷΈΛ0QJOJPO%ZOBNJDT Λ༻͍ͯγϡϛϨʔγϣϯΛߦ͍໌Β͔ʹ͢Δ -
10 0QJOJPO%ZOBNJDT Opinion Dynamics l ߹ҙܗରཱͳͲʹࢸΔ·Ͱʹੜ͡Δɺݸਓؒͷ ҙݟٞͷਪҠΛϞσϦϯά͢ΔͨΊͷख๏ l ࣾձͷ߹ҙܗબڍͳͲͷԠ༻ʹ׆༻͞ΕΔ l
ҙݟΛ࣋ͭݸਓͱަྲྀ͢Δ͜ͱͰɺ֤ݸਓͷ࣋ͭ ҙݟ͕มԽ͍ͯ͘͠ͱ͍͏ݱΛཧϞσϧʹ Αͬͯදݱͨ͠ͷ l ࠓճͷݚڀͰɺ0QJOJPO%ZOBNJDTΛ༻͍ͯ 1BSUJTBO4PSUJOH͕ͲͷΑ͏ͳঢ়گͰੜ͡Δͷ͔ Λݕূ -
11 0QJOJPO%ZOBNJDT ベースモデル l "YFMSPEͷϞσϧΛϕʔε l ֤ݸਓ͕ଟ࣍ݩͷจԽతಛΛ࣋ͭ จԽతಛ l ྡਓͱަྲྀͨ͠ޙʹྡਓͷจԽతಛͷҰ෦ΛɺྡਓͷྨࣅʹԠͯ֬͡Ͱ฿͢Δ
)PNPQIJMZ l ར༻Ϟσϧ 𝑤 𝑤 ×𝑤ͷ֨ࢠ্ͷۭؒʹΤʔδΣϯτ ΤʔδΣϯτ i ͷಛੑɿ 𝐷! ∈ [1, 𝑚] ΤʔδΣϯτ i ͷౘɿ 𝑆! ∈ [1,2] 𝐷" = 0,1,4,5,2,1 𝑆" = 1 𝐷# = 0,1,1,1,3,1 𝑆# = 1 -
12 0QJOJPO%ZOBNJDT ベースモデル l "YFMSPEͷϞσϧΛϕʔε l ֤ݸਓ͕ଟ࣍ݩͷจԽతಛΛ࣋ͭ จԽతಛ l ྡਓͱަྲྀͨ͠ޙʹྡਓͷจԽతಛͷҰ෦ΛɺྡਓͷྨࣅʹԠͯ֬͡Ͱ฿͢Δ
)PNPQIJMZ l ར༻Ϟσϧ ֬𝛾ʹԠͯ͡ϥϯμϜͳΤʔδΣϯ τͱަྲྀ ֬1 − 𝛾ͰྡΤʔδΣ ϯτͱަྲྀ ಛੑౘ͕͍ۙྡΤʔδΣϯτ ͱަྲྀ IPNPQIJMZ ަྲྀ 𝑤 -
13 0QJOJPO%ZOBNJDT ベースモデル l "YFMSPEͷϞσϧΛϕʔε l ֤ݸਓ͕ଟ࣍ݩͷจԽతಛΛ࣋ͭ จԽతಛ l ྡਓͱަྲྀͨ͠ޙʹྡਓͷจԽతಛͷҰ෦ΛɺྡਓͷྨࣅʹԠͯ֬͡Ͱ฿͢Δ
)PNPQIJMZ l ར༻Ϟσϧ ަྲྀʹΑͬͯɺλʔήοτͱͳΔ ΤʔδΣϯτͷಛੑ͕ަྲྀ૬खͷ ಛੑʹมԽ ަྲྀ 𝑤 𝐷" = 0,1,4,5,2,1 𝑆" = 1 𝐷# = 0,1,1,1,3,1 𝑆# = 1 -
14 0QJOJPO%ZOBNJDT ベースモデル l "YFMSPEͷϞσϧΛϕʔε l ֤ݸਓ͕ଟ࣍ݩͷจԽతಛΛ࣋ͭ จԽతಛ l ྡਓͱަྲྀͨ͠ޙʹྡਓͷจԽతಛͷҰ෦ΛɺྡਓͷྨࣅʹԠͯ֬͡Ͱ฿͢Δ
)PNPQIJMZ l ར༻Ϟσϧ ަྲྀʹΑͬͯɺλʔήοτͱͳΔ ΤʔδΣϯτͷಛੑ͕ަྲྀ૬खͷ ಛੑʹมԽ 𝐷# = 0,1, 𝟒, 1,3,1 𝑆# = 1 ަྲྀ 𝑤 𝐷" = 0,1,4,5,2,1 𝑆" = 1 -
15 0QJOJPO%ZOBNJDT ベースモデル l "YFMSPEͷϞσϧΛϕʔε l ֤ݸਓ͕ଟ࣍ݩͷจԽతಛΛ࣋ͭ จԽతಛ l ྡਓͱަྲྀͨ͠ޙʹྡਓͷจԽతಛͷҰ෦ΛɺྡਓͷྨࣅʹԠͯ֬͡Ͱ฿͢Δ
)PNPQIJMZ l ύϥϝʔλ l ℎҟͳΔͷ͔ΒͷӨڹΛड͚͢͞ )PNPQIJMZ খ͍͞ͱҟͳΔੑ࣭Λ࣋ͬͨΤʔδΣϯτͱ ަྲྀ͘͢͠ͳΔ l 𝛾ϥϯμϜͳΤʔδΣϯτͱަྲྀ͢Δ֬ l ωοτϫʔΫͷධՁΨ l ಉ͡ౘͷத͔ΓͰಉ͡ಈతੑ࣭Λ࣋ͪɺҧ͏ౘʹ ͦͷಈతੑ࣭͕ແ͍ͱ͍͏ঢ়گ 4PSUJOH ͷఔ l େ͖͍ͩͱɺ4PSUJOH͕ੜ͍ͯ͡Δ 𝐷# = 0,1, 𝟒, 1,3,1 𝑆# = 1 ަྲྀ 𝑤 𝐷" = 0,1,4,5,2,1 𝑆" = 1 -
20 ·ͱΊ l 1PMBSJ[BUJPOͷจݙ͔ΒɺۃԽΛੜ͡Δ͜ͱΛઆ໌͢ΔΤίʔνΣϯόʔͱҟͳΔ ԾઆΛఏࣔ l ଞͷࢹʹ৮ΕΔ͜ͱ͕ແ͘ͳΔΤίʔνΣϯόʔͰͳ͘ɺ֎෦ͱަྲྀ͢Δ͜ͱͰೋۃԽ ͕ੜ͡Δ͜ͱΛઆ໌͢ΔͨΊͷϞσϧΛఏҊ l ہॴతͳ૬ޓ࡞༻͕ϝΠϯͰ͋Ε༷ʑͳҬͰ࣏จԽ͕ੜ͡ΔɺҰํͰɺ֎෦ͱͷ૬ޓ࡞༻͕ଟ͘ͳΕ
֤Ҭͷ࣏จԽ͕݁ͼ͖ͭ୯Ұͷౘత྾͕ੜ͡Δ l ౘੑ͕ଟ͘ͷ࣏తཱจԽతᅂΛؚ༗͢ΔΑ͏ʹͳΔ݁Ռɺఢରऀʹର͢Δෆ৴ ݏѱΛಛͱ͢ΔೋۃԽ͕ੜ͡Δ͜ͱɺͭ·Γ"GGFDUJWF1PMBSJ[BUJPOΛࣔࠦ l &DIP$IBNCFSͱҟͳΔԾઆɾઆ໌ϞσϧͷఏࣔΛߦͬͨͷͰɺೋۃԽͷ࣮ࡍͷσʔλ ʹద༻Մೳ͔Ͳ͏͔ͷݕ౼͕ࠓޙඞཁͦ͏