Bridging Hearts: Developing and Validating Experimental Manipulations of Closeness Motivation in Romantic Relationships

ABSTRACT This study aimed to validate experimental manipulations to increase state closeness motivation toward the romantic partner which are implemented in everyday life via smartphone. Drawing on motive disposition theory and the Zurich Model of Social Motivation, we derived three motivation‐arousing mechanisms—incentive, disincentive, and deprivation—and implemented 18 manipulation variants across six media formats (videos, audio stories, podcasts, songs, guided memories, and personal photos). In a within‐person experience‐sampling design over 8 days, 269 participants in romantic relationships completed one manipulation or control task per day in their daily life. Sequential Bayesian hypothesis testing with Bayes factors was used to efficiently evaluate each manipulation's effectiveness. Results showed that 10 of the tested manipulation variants reliably increased state closeness motivation; four failed to do so, and four variants yielded inconclusive evidence. Construct validation analyses showed mixed results. While some variants did precisely manipulate closeness motivation, other variants also influenced affective states, agency‐related motivations, or relationship evaluations, partly to a larger extent than closeness motivation itself. Overall, the effective manipulation variants provide a flexible toolbox for future research in naturalistic settings.