Young adults are deemed to possess common characteristics that make them a relatively homogeneous group, rightly distinguishable from older cohorts. Having as a main toolkit the partisan influence from their family socialization, they gradually develop firm political attitudes as they accumulate political experience. However, this process is typically regarded as a black box, lacking a systematic examination of how it actually takes place. Thus, our knowledge about the political trajectory of young people does not typically go beyond the assertion that parental influence gradually wanes and that young adults progressively develop firm attitudes as they accumulate more experience with the political world. The goal of this study is to open this black box by focusing on three factors that are perceived to affect this process, namely the role of family, elections and political events. In so doing, it tries to address the following questions: what determines the durability of the parental partisan link? Why manifesting preference into actual vote might be important? What is the role of political events in shaping people’s attitudes? Regarding the first question, I show that, contrary to conventional wisdom, parental politicization may contribute in breaking the intergenerational transmission of partisan predispositions. A young Republican who comes from a politicized home is used to talk about politics and this is also what she does when she enters new social contexts. In so doing, she becomes exposed to new political forces that may alter her prior partisan beliefs. This is especially true when the political mood during her early adulthood contradicts the partisan lessons of the family. Regarding the second question, I use a natural experiment to estimate the impact of the act of voting on partisan change, showing that its effect in reinforcing prior preferences is important only among the youth. Moreover, by ruling out various alternative explanations, I argue that this is mainly an effect attributed to the psychological forces of cognitive dissonance that stem from the act of voting. Last but not least, by testing three salient political events, I find that their impact among young adults is much stronger than among older age groups. When taken as a whole, the findings speak in favor of a particular pattern of attitudinal crystallization, namely that proposed by the Impressionable Years thesis: there is a developmental process in how people form well defined preferences but the crucial route in this trajectory is early adulthood. This is the period within which preferences are questioned, intensified and eventually crystallized.