Uncertainty moderates the emotional consequences of reappraisal, social sharing, and rumination in daily life.

People must often wait for important but uncertain outcomes, like medical results or job offers. During such uncertain waiting periods, there is uncertainty around an outcome that people have minimal control over. Uncertainty makes these periods emotionally challenging, raising the possibility that emotion regulation strategies may have different effects while people wait for an uncertain outcome versus after they learn that outcome. To test this possibility, we conducted secondary analyses of an experience sampling study following 101 Belgian University students for 9 days as they waited for (uncertain period), and then received (certain period), consequential exam grades. Across 8,275 observations, we tested the effects of six emotion regulation strategies on positive and negative emotions about anticipated, and then actual, grades. Regardless of uncertainty, acceptance was consistently beneficial for short-term emotional well-being, and expressive suppression was consistently detrimental. However, the consequences of rumination, social sharing, and reappraisal differed when the outcome was uncertain versus certain. Rumination was more detrimental to short-term emotional well-being during the uncertain than certain period, while social sharing and reappraisal were detrimental in the uncertain period but beneficial in the certain period. These findings suggest uncertainty moderates the short-term effectiveness of some emotion regulation strategies in an academic context, which may exacerbate the emotional challenges of uncertain waiting periods. (PsycInfo Database Record (c) 2024 APA, all rights reserved).