The Role of Monitoring and Acceptance in Daily Affective Stress Reactivity: An Ambulatory Assessment Study

Objectives Affective stress reactivity is a vulnerability factor for mental health. The central mindfulness facets, monitoring and acceptance, are associated with differential patterns of affective stress reactivity. This study investigated whether monitoring amplifies and whether acceptance attenuates affective stress reactivity in daily life. Additionally, we tested a central tenet of Monitor and Acceptance Theory, namely, whether monitoring and acceptance interact in predicting affective stress reactivity. Method A total of 211 healthy adult participants completed self-reported measures of trait monitoring and trait acceptance in person during a group session using computers. They then used a smartphone app for a 7-day ambulatory assessment of momentary stress and negative affect in their daily lives. Results We calculated separate models for acceptance facets — nonjudgment and nonreactivity. Multilevel modeling revealed cross-level interactions for both monitoring (i.e., Observing) and acceptance (i.e., Nonjudgment and Nonreactivity). Monitoring was linked to an amplification in affective stress reactivity. When monitoring was high, stress was associated with a greater increase in negative affect than when monitoring was low. Acceptance, by contrast, was linked to a buffering in affective stress reactivity: When acceptance was high, stress was associated with an attenuated increase in negative affect compared to when acceptance was low. Monitoring did not interact with either of the acceptance subscales in predicting affective stress reactivity. Conclusions The findings indicate that monitoring one’s experiences is associated with increased stress reactivity, while acceptance correlates with reduced reactivity, highlighting their relevant roles in this process. We discuss implications of these findings. Preregistration This study is not preregistered.