Penelitian ini memberikan penjelasan mengenai dampak penggunaan sosial media dalam konteks komunikasi instruksional, khususnya pada hubungan interpersonal pendidik dengan peserta didik. Penelitian ini menggunakan model eksperimen klasik dengan adanya kelompok eksperimen dan kontrol serta menerapkan kerangka teoretis mediated self-disclosure dan pengaruhnya terhadap perceived credibility yang sebelumnya dikembangkan oleh Mazer et al (2009). Dengan melibatkan 62 responden siswa kelas X SMA Negeri 1 Gresik dalam dua kelompok penelitian, eksperimen ini menemukan adanya pengaruh mediated selfdisclosure pendidik via Facebook terhadap perceived credibility-nya dengan melihat adanya perbedaan yang signifikan antara skor rata-rata kelompok pada pretest dan posttest. Pada penelitian ini, mediated self-disclosure yang diterapkan pada kelompok eksperimen meresultankan persepsi kredibilitas pendidik yang lebih negatif pada pendidik dibandingkan saat tatap muka langsung, khususnya terkait persepsi akan itikad baik pendidik. Penelitian ini merekomendasikan komunikasi stratejik bagi pendidik dalam bentuk pengaturan informasi dan pesanpesan yang ditampilkan pendidik dalam Facebook manakala berinteraksi dengan peserta didiknya dalam media sosial Facebook.

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This research investigated and explained the influence of social media use under the context of instructional communication, specifically in understanding the teacher-student relationships. The research used classical experiment design with the one experiment and control group and applied theoretical framework regarding the influence of mediated self-disclosure to perceived credibility, which was previously developed by Mazer et al (2009). By involving 62 students from SMA Negeri 1 Gresik as respondents in two research groups, the result of the experiment yields that there is influence of teacher’s mediated self-disclosure through Facebook to its perceived credibility. The conclusion was drawn from seeing a significant difference between experiment and control group mean scores in pretest and posttest. The research reveals that mediated self-disclosure results to a more negative perception of credibility of the students towards the teacher especially on its perceived goodwill in comparison to face-to-face self-disclosure. Lastly, this research, therefore, recommends a strategic communications for the teachers, by managing information and messages they disclose in social media while they are communicating with their students in Facebook.