Sunken costs and desired plans: examining different types of investments in close relationships.

Although the concept of investments in romantic relationships has featured prominently in close relationships research, there have been no empirical analyses of different types of investments and their possible differential predictive power regarding relationship state or fate. With data from five independent samples, the authors offer and examine investments that differ in terms of their timing (past vs. planned) and materiality (tangible vs. intangible). Cross-sectional and longitudinal tests of hypotheses regarding these investment types provide evidence for the utility of considering specific types of investments in predicting a variety of important relationship factors, including commitment, stability, and the impact of breakup on relationship partners. Intangible investments and planned investments were found to be particularly robust predictors of key relational states and outcomes.