Social network media (social media), represented by Facebook and X (Twitter), have become popular. However, opportunities to learn about social media are limited, and people are often only informed about the risks of its use. Teenagers, in particular, are thought to be overconfident and naïve in their trust of social media. The aim of this study is to change and reconstruct learners’ attitudes towards social media by educating them through using our social media simulator. Our social media simulator—a serious game—provides learners with an objective view of how their own interpretation and representation of information in social media differs from that of others. We use this simulator to teach media literacy to university students. Our study analysed whether learners’ attitudes towards social media changed based on (i) pre- and post-learning confidence questionnaires and (ii) changes in judgements and behaviour in the simulator. The simulator has been shown to be particularly effective in shaping attitudes of those learners who were overconfident and naïve in their social media use.