The increasing use of digital screens—computers, smartphones, tablets, and televisions—has significant psychological effects on human behaviour, cognition, emotions, and well-being. Known as "screen time", this phenomenon has been widely studied, but its impact on identity formation in the digital age is less understood. This literature review aims to explore how screen time influences identity formation, focusing on four aspects of identity: biological, psychological, social, and cultural. Additionally, the study considers screen time from four perspectives: biological, psychological, social, and cultural time. By analysing existing research, we identified overlapping approaches and interconnected relationships between these identity aspects and screen time. Based on this analysis, we propose a unified model called the "Screen Time Identity Formation"-model (STIF-model), which provides a framework for examining the relationship between screen use and identity formation. This model offers a comprehensive approach to understanding how individuals form their identities in the context of digital screens, how these screens influence their relationships with others, and how they shape overall life experiences in a screen-dominated environment. The STIF model offers a new perspective on identity formation in the digital age, emphasizing the deep connection between screen time and personal development.