ORCID

0000-0002-6737-7377

Keywords

Social media, Online harm, Marginalized users, Peer influence, Radicalization, Mental health, Social ecology, Privacy, Human-computer interaction

Subject Categories

Communication | Communication Technology and New Media

Abstract

Social media has reshaped how people connect, communicate, and influence one another, yet these environments also create harms that disproportionately affect marginalized users. Participation in online communities can expose users to identity-based harassment, emotional distress, and the normalization of harmful attitudes, shaping identity, well-being, and participation online and offline. Prior work has documented many forms of online harm, yet less is understood about how harmful norms and behaviors are reinforced across different forms of social media interaction, from private direct messages to online communities. Guided by the Social Ecological Model, this dissertation investigates how online harms toward marginalized users emerge across interconnected layers of social media interaction and how peer interactions can mitigate such harms. It addresses these dynamics through three studies examining private direct messages, public community interactions, and controlled micro-interactions. Study 1 examines private Instagram direct messages among LGBTQ+ and heterosexual youth, showing that LGBTQ+ youth experience mental health benefits from certain forms of private messaging that heterosexual youth do not. Study 2 analyzes participation in a misogynistic extremist subreddit to reveal how harmful norms are reinforced and disseminated within online communities. Building on these insights, Study 3 experimentally examines how peer comments shape willingness to engage in harmful sharing decisions. Together, these studies demonstrate how beneficial and harmful norms spread across multiple levels of social media interaction and identify when peer influence can reduce harmful behavior. The findings extend social ecological approaches in Human-Computer Interaction and provide insights for designing safer and more inclusive social media spaces.

Completion Date

2026

Semester

Summer

Committee Chair

Yan Solihin

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Computer Science

Format

PDF

Document Type

Dissertation

Language

English

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