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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

taichi_murayama
February 16, 2023

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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  1. 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. 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༗໊δϟʔφϧ͔Βग़൛͞Εͨ࿦จ l Peter TörnbergࢯʹΑΔ୯ஶ l ΞϜεςϧμϜେֶॴଐɻ l ෳࡶܥ΍ίϯϐϡʔλʔαΠΤϯεΛ༻͍ͨɺ஍ཧۭؒʹ͓͚Δ෼ۃԽ΍ϑΣΠΫχϡʔεͷ෼ੳʹैࣄ l 1-P4 POFl&DIPDIBNCFSTBOEWJSBMNJTJOGPSNBUJPO.PEFMJOHGBLFOFXTBTDPNQMFY DPOUBHJPOzͳͲ͕༗໊ l ͲΜͳ࿦จʁ ιʔγϟϧϝσΟΞͳͲͰݟΒΕΔ෼ۃԽ͕൓ରҙݟʹ৮Εͳ͍͜ͱʹΑΔΤίʔνΣϯόʔʹΑͬͯੜ͡Δ΋ͷ Ͱ͸ͳ͘ɺΉ͠ΖɺιʔγϟϧϝσΟΞʹΑͬͯ֎ͷਓʑͱަྲྀ͢ΔΑ͏ʹͳΓ֤஍Ҭʹ͓͍ͯଘࡏͨ͠ଟ༷ੑ͕ ୯७ͳೋۃ΁ͱz4PSUJOHz ͞ΕΔ͜ͱΛΦϐχΦϯμΠφϛοΫεͱ͍͏ख๏Λ༻͍ͯݕূ
  3. 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 ൃ৴͞ΕͨϝοηʔδΛ֦େ͠ɺ൓࿦͕དྷͳ͘ͳΔՄೳੑΛ࣋ͭࣅͨ΋ͷಉ࢜Ͱܨ͕ͬͨด ͟͞Εۭͨؒͷ͜ͱ l ରཱ͢ΔϢʔβ΍άϧʔϓͷҙݟ͔Βݽཱ͢ΔΤίʔνΣϯόʔ͸ೋۃԽͷओͳཁҼʢͱߟ ͑ΒΕͯΔʣ l ภͬͨ৘ใ΍Ұ෦ͷάϧʔϓͰϑΣΠΫχϡʔε͹͔ΓྲྀΕΔͳͲѱӨڹ
  4. 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
  5. 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༗͸͠ͳ͍͕ɺ൓ରҙݟʹ;ΕΔ PS൓Ԡ͢Δ͜ͱ͸සൟʹੜ͡Δ 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).
  6. 8 Partisan Sortingが⽣じている可能性 ४උ l σδλϧϝσΟΞ͸ަྲྀΛଅ͠੓࣏తͳݴ͍૪͍ʹר͖ࠐΉ͜ͱͰɺͲͪΒͷཱ৔ʹཱͭ΂͖͔Λٻ ΊΔޮՌΛ࣋ͭ ಛʹ࠷ۙͷΞϝϦΧ l ΞϝϦΧͷେ੓ౘ͸੓࣏తͳ΋ͷ͚ͩͰͳ͘ɺফඅߦಈ΍ݸਓͷಓಙ·Ͱ΋ٵऩ͠zDVMUVSFXBSzΛ

    Ҿ͖ى͍ͯ͜͠Δ "GGFDUJWF1PMBSJ[BUJPOͱͷؔ࿈ l ଟ༷ͳࣾձΞΠσϯςΟςΟΛΧόʔ͠ɺͭͷΞΠσϯςΟςΟʹ෼ׂ͢Δͱ͍͏ΞϝϦΧࣾձͷ࠷ ۙ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).
  7. 10 0QJOJPO%ZOBNJDT Opinion Dynamics l ߹ҙܗ੒΍ରཱͳͲʹࢸΔ·Ͱʹੜ͡Δɺݸਓؒͷ ҙݟ΍ٞ࿦ͷਪҠΛϞσϦϯά͢ΔͨΊͷख๏ l ࣾձͷ߹ҙܗ੒΍બڍͳͲ΁ͷԠ༻ʹ׆༻͞ΕΔ l

    ҙݟΛ࣋ͭݸਓͱަྲྀ͢Δ͜ͱͰɺ֤ݸਓͷ࣋ͭ ҙݟ͕มԽ͍ͯ͘͠ͱ͍͏ݱ৅Λ਺ཧϞσϧʹ Αͬͯදݱͨ͠΋ͷ l ࠓճͷݚڀͰ͸ɺ0QJOJPO%ZOBNJDTΛ༻͍ͯ 1BSUJTBO4PSUJOH͕ͲͷΑ͏ͳঢ়گͰੜ͡Δͷ͔ Λݕূ
  8. 11 0QJOJPO%ZOBNJDT ベースモデル l "YFMSPEͷϞσϧΛϕʔε l ֤ݸਓ͕ଟ࣍ݩͷจԽతಛ௃Λ࣋ͭ จԽతಛ௃ l ྡਓͱަྲྀͨ͠ޙʹྡਓͷจԽతಛ௃ͷҰ෦Λɺྡਓͷྨࣅ౓ʹԠͯ֬͡཰Ͱ໛฿͢Δ

    )PNPQIJMZ l ར༻Ϟσϧ 𝑤 𝑤 ×𝑤ͷ֨ࢠ্ͷۭؒʹΤʔδΣϯτ ΤʔδΣϯτ i ͷಛੑɿ 𝐷! ∈ [1, 𝑚] ΤʔδΣϯτ i ͷౘ೿ɿ 𝑆! ∈ [1,2] 𝐷" = 0,1,4,5,2,1 𝑆" = 1 𝐷# = 0,1,1,1,3,1 𝑆# = 1
  9. 12 0QJOJPO%ZOBNJDT ベースモデル l "YFMSPEͷϞσϧΛϕʔε l ֤ݸਓ͕ଟ࣍ݩͷจԽతಛ௃Λ࣋ͭ จԽతಛ௃ l ྡਓͱަྲྀͨ͠ޙʹྡਓͷจԽతಛ௃ͷҰ෦Λɺྡਓͷྨࣅ౓ʹԠͯ֬͡཰Ͱ໛฿͢Δ

    )PNPQIJMZ l ར༻Ϟσϧ ֬཰𝛾ʹԠͯ͡ϥϯμϜͳΤʔδΣϯ τͱަྲྀ ֬཰1 − 𝛾Ͱྡ઀ΤʔδΣ ϯτͱަྲྀ ಛੑ΍ౘ೿͕͍ۙྡ઀ΤʔδΣϯτ ͱަྲྀ IPNPQIJMZ ަྲྀ 𝑤
  10. 13 0QJOJPO%ZOBNJDT ベースモデル l "YFMSPEͷϞσϧΛϕʔε l ֤ݸਓ͕ଟ࣍ݩͷจԽతಛ௃Λ࣋ͭ จԽతಛ௃ l ྡਓͱަྲྀͨ͠ޙʹྡਓͷจԽతಛ௃ͷҰ෦Λɺྡਓͷྨࣅ౓ʹԠͯ֬͡཰Ͱ໛฿͢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
  11. 14 0QJOJPO%ZOBNJDT ベースモデル l "YFMSPEͷϞσϧΛϕʔε l ֤ݸਓ͕ଟ࣍ݩͷจԽతಛ௃Λ࣋ͭ จԽతಛ௃ l ྡਓͱަྲྀͨ͠ޙʹྡਓͷจԽతಛ௃ͷҰ෦Λɺྡਓͷྨࣅ౓ʹԠͯ֬͡཰Ͱ໛฿͢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
  12. 15 0QJOJPO%ZOBNJDT ベースモデル l "YFMSPEͷϞσϧΛϕʔε l ֤ݸਓ͕ଟ࣍ݩͷจԽతಛ௃Λ࣋ͭ จԽతಛ௃ l ྡਓͱަྲྀͨ͠ޙʹྡਓͷจԽతಛ௃ͷҰ෦Λɺྡਓͷྨࣅ౓ʹԠͯ֬͡཰Ͱ໛฿͢Δ

    )PNPQIJMZ l ύϥϝʔλ l ℎҟͳΔ΋ͷ͔ΒͷӨڹΛड͚΍͢͞ )PNPQIJMZ খ͍͞ͱҟͳΔੑ࣭Λ࣋ͬͨΤʔδΣϯτͱ ަྲྀ͠΍͘͢ͳΔ l 𝛾ϥϯμϜͳΤʔδΣϯτͱަྲྀ͢Δ֬཰ l ωοτϫʔΫͷධՁΨ l ಉ͡ౘ೿ͷத͹͔ΓͰಉ͡ಈతੑ࣭Λ࣋ͪɺҧ͏ౘ೿ʹ͸ ͦͷಈతੑ࣭͕ແ͍ͱ͍͏ঢ়گ 4PSUJOH ͷఔ౓ l େ͖͍஋ͩͱɺ4PSUJOH͕ੜ͍ͯ͡Δ 𝐷# = 0,1, 𝟒, 1,3,1 𝑆# = 1 ަྲྀ 𝑤 𝐷" = 0,1,4,5,2,1 𝑆" = 1
  13. 20 ·ͱΊ l 1PMBSJ[BUJPOͷจݙ͔Βɺ෼ۃԽΛੜ͡Δ͜ͱΛઆ໌͢ΔΤίʔνΣϯόʔͱҟͳΔ ԾઆΛఏࣔ l ଞͷࢹ఺ʹ৮ΕΔ͜ͱ͕ແ͘ͳΔΤίʔνΣϯόʔͰ͸ͳ͘ɺ֎෦ͱަྲྀ͢Δ͜ͱͰೋۃԽ ͕ੜ͡Δ͜ͱΛઆ໌͢ΔͨΊͷϞσϧΛఏҊ l ہॴతͳ૬ޓ࡞༻͕ϝΠϯͰ͋Ε͹༷ʑͳ஍ҬͰ੓࣏จԽ͕ੜ͡ΔɺҰํͰɺ֎෦ͱͷ૬ޓ࡞༻͕ଟ͘ͳΕ͹

    ֤஋Ҭͷ੓࣏จԽ͕݁ͼ͖ͭ୯Ұͷౘ೿త෼྾͕ੜ͡Δ l ౘ೿ੑ͕ଟ͘ͷ੓࣏తཱ৔΍จԽతᅂ޷Λؚ༗͢ΔΑ͏ʹͳΔ݁Ռɺఢରऀʹର͢Δෆ৴΍ ݏѱΛಛ௃ͱ͢ΔೋۃԽ͕ੜ͡Δ͜ͱɺͭ·Γ"GGFDUJWF1PMBSJ[BUJPOΛࣔࠦ l &DIP$IBNCFSͱ͸ҟͳΔԾઆɾઆ໌ϞσϧͷఏࣔΛߦͬͨͷͰɺೋۃԽͷ࣮ࡍͷσʔλ ʹద༻Մೳ͔Ͳ͏͔ͷݕ౼͕ࠓޙඞཁͦ͏