African youth and the future of democracy: How social media and cohort size shape political participation

African youth constitute the world’s youngest and fastest-growing population, making their political engagement central to the future of democratic governance on the continent. Yet, despite their demographic weight, the determinants of young Africans’ political behaviour, especially their decisions to vote or protest, remain insufficiently understood. This study addresses this gap by examining how two structural forces shaping contemporary African politics—youth cohort size and social media usage—individually and jointly influence youth political participation. Building on emerging debates in political demography and digital politics, the study tests three hypotheses: that larger youth cohorts reduce voting but increase protest participation (H1); that social media usage depresses voting while encouraging protest (H2); and that social media amplifies the political effects of youth cohort size (H3). Using Afrobarometer survey data from 40 African countries (2016–2023), combined with demographic, economic, and political contextual indicators, the study employs multilevel binary logistic regression models with country-clustered standard errors and interaction analyses. The findings challenge and refine existing theories. First, contrary to expectations, larger youth cohorts are associated with higher, not lower, likelihood of voting, and have no direct effect on protest participation. Second, social media use strongly predicts political behaviour, with daily and occasional users significantly less likely to vote but more likely to participate in protests. Third, the interaction analyses show that daily social media use in youth-dense societies decreases electoral participation, while occasional social media use in countries with medium-sized youth cohorts (30–50%) increases protest participation. These effects, although modest, are robust across multiple model specifications. The results offer several important insights. They suggest that the political consequences of Africa’s youth bulge are more complex than conventional “youth-unrest” narratives imply, and that digital media—not demographic size alone—plays a decisive role in shaping political expression. The findings also reveal that the effects of social media are contingent on demographic structure, indicating non-linear socialisation and mobilisation dynamics. Theoretically, the study advances a more integrated framework linking political demography and digital-era political behaviour, demonstrating that demographic composition conditions how digital information environments shape political participation. These insights highlight the need for democratic institutions to adapt to the dual forces of demographic expansion and digital transformation in order to effectively engage Africa’s rising generation of young citizens.