Expressing gratitude to a partner leads to more relationship maintenance behavior.

We proposed that expressing gratitude would increase positive perception of a relationship partner, thereby increasing comfort in expressing relationship concerns, which is a form of relationship maintenance. Study 1 (n = 159) showed a relationship between naturally occurring expressions of gratitude and comfort in voicing relationship concerns. Study 2 (n = 178) provided longitudinal evidence for direction of effects because Time 1 gratitude expression predicted Time 2 comfort in voicing relationship concerns, controlling for baseline comfort in voicing relationship concerns. Study 3 (n = 225) showed that expressing gratitude to a friend did increase voicing relationship concerns, compared with positive thought and neutral control conditions. In Study 4 (n = 74), we explored the mechanism through a longitudinal, experimental design and found that participants assigned to express gratitude reported higher comfort voicing concerns and more positive perception of partner than did control participants. Moreover, positive perception of partner mediated the relationship between condition and comfort in voicing relationship concerns.