Much of the literature on democratic transitions presumes that mass attitudes are important for the consolidation of democracies but not for the process of democratization. We challenge this premise on the basis of human development theory. From the perspective of this theory, democratization is an emancipative achievement that should be fuelled by broader emancipative forces among the population. Using the Values Surveys we measure these emancipative forces by people’s liberty aspirations, showing that mass liberty aspirations have a causal effect on a society’s democratic development. No other factor, not GDP/capita and not social capital, can explain away the effect of liberty aspirations on democratization. We conclude that human development theory illuminates emancipative forces in democratization that have so far been neglected.