According to attachment theory, people construct "internal working models"-mental representations of the self and the social world-that play a critical role in guiding their interpersonal behavior and affective experience across time. Unfortunately, we do not have a good understanding of how stable these representations are, nor do we have a consensual understanding of the dynamic processes that promote continuity and change in attachment representations. Some researchers, for example, have suggested that working models are trait-like in the sense that they are enduring features of people-representations that facilitate stability in thoughts, feelings, and behaviors across time and context. In contrast, some researchers have argued that working models behave in a contextual manner, with different features of those models being activated under different conditions, ultimately leading to instability in attachment over time. The primary aims of the proposed research are to answer three critical questions of the dynamics of attachment: Are patterns of stability and change in adult attachment more consistent with the predictions of a trait-like model, a contextual model, or some combination of the two? Second, can basic personality traits, such as neuroticism, explain empirical patterns of attachment stability? And, third, how do attachment representations influence-and get influenced by-relational experiences? To accomplish these aims, individuals in dating/marital relationships will be recruited to complete self-report measures of attachment, personality, and interpersonal experiences weekly (Sample 1) or bimonthly (Sample 2) for twelve months. The proposed study will provide the first rigorous investigation into these fundamental theoretical questions. Moreover, because the proposed research addresses a set of issues that are of broad significance in social and personality psychology (e.g., What are the dynamic mechanisms underlying stability and change?), this investigation has the potential to facilitate the development of a generalized framework for understanding the dynamics of stability and change in personality, affective, and social processes more generally.