Digital Sociology and Social Media: Digital Identity and Behavioural Impact of Social Networking on Generation Z

The pervasive integration of social networking platformsTikTok, WhatsApp, Instagram, X (formerly Twitter), and artificial intelligence (AI) tools into the daily lives of Generation Z (born 1997–2012) represents one of the most consequential socio-technological transformations of the twenty-first century. This study provides a sociological assessment of digital identity construction and the behavioural impacts of these platforms, anchored on Goffman's Dramaturgical Model, Bourdieu's Social Capital Theory, Foucault's Surveillance Theory, Zuboff's Surveillance Capitalism framework, and Bauman's Liquid Modernity. A cross-sectional mixed-methods design was employed, combining a structured survey of 360 Gen Z adults drawn from Nigerian universities and online panels, supplemented by in-depth qualitative interviews with 40 purposively selected participants. Quantitative findings reveal that 72.7 percent of respondents maintain differentiated self-presentations across platforms, 66.6 percent report that likes and follower counts affect their self-esteem, and 47.7 percent experience social media-related anxiety always or often. AI tools have modified online self-expression for 41.1 percent of respondents, introducing new dimensions of identity uncertainty. All four null hypotheses were rejected at p < 0.001, confirming significant associations between platform use intensity and mental health outcomes, digital identity fragmentation, self-esteem differentials, and AI-mediated authenticity concerns. Thematic analysis of qualitative data generated four major themes: algorithmic selfhood, performative pressure and curated identity, parasocial bonds and relational displacement, and AI-mediated identity uncertainty. The study concludes that social networking platforms are architecturally designed environments that actively shape Gen Z identities, behaviours, and psychological wellbeing through surveillance, algorithmic curation, and engagement optimisation. Recommendations encompass platform design reform, digital literacy education, mental health policy reform, and future longitudinal research.