The impressionable years thesis asserts that early adulthood is accompanied by increased attitudinal vulnerability. Although there is tentative empirical evidence to support this idea, it remains unclear whether this sensitivity is due to exposure to change-inducing circumstances, typically encountered in early adulthood, or due to the weight attached by young people to new information. I address this question, focusing on a political event-the Watergate-that offers a test of youth's heightened susceptibility, holding exposure constant. The results confirm the impressionable years thesis and shed light on how it is most likely to be manifested empirically. Downloaded from Dinas 869 this event on other early impressions (Schuman and Corning 2012, 3).Although both processes are important, only the second gives to early adulthood an intrinsic role in the development of political attitudes. Moreover, this is the mechanism that is referred to as youth's "openness to change" (Alwin, Cohen, and Newcomb 1991, 24;Stoker and Jennings 2008). It is thus crucial to disentangle the two mechanisms. The existing literature, however, has not been very informative in this respect. As Bartels (2001, 13) notes, "[a]nalysts of generational politics have pointed to a variety of potentially relevant psychological and sociological processes, but have done little to pursue their specific implications or even to distinguish clearly among them."This study tries to shed light on both these issues. With regard to the first, I illustrate that there are two, nonmutually exclusive, manifestations of youth sensitivity. I argue that previous studies have only captured one of them. With regard to the second, I use a design that improves our ability to examine youth sensitivity, despite different levels of exposure. More specifically, I focus on a political shock, the Watergate scandal, salient enough to ensure that all individuals have received the information. Using data that enable the identification of its effect on relatively weak assumptions, I find considerable support for the hypothesis that young adults are more susceptible to new information. The analysis, however, indicates that this increased sensitivity is realized through only one of the two possible behavioral paths.