Induced rumination in everyday life: Advancing research approaches to study rumination

Rumination has been proposed as an important cognitive risk factor for depressive states. Experimental studies in the laboratory have demonstrated negative effects of induced rumination on mood and cognition. However, it is not known whether respective effects can also be generalized to naturalistic contexts. Therefore, the present study transferred rumination inductions to daily life within a novel experimental ambulatory assessment approach. Forty young adults carried palmtop computers for 2 days with ten assessments of momentary ruminative self-focus and mood per day. On one of the 2 days (induction day), participants were subjected to 3-min rumination inductions at each assessment (cross-over design). Analyses revealed that the rumination inductions immediately increased momentary ruminative self-focus and deteriorated positive mood. Higher increases in ruminative self-focus after inductions were linked to stronger reductions in positive mood. Momentary preinduction ruminative self-focus and mood on the induction day did not differ from momentary ruminative self-focus and mood on the noninduction day, indicating a lack of significant longer-term effects over the day. This is the first study revealing immediate effects of induced rumination in daily life, thereby assuring external validity of previous laboratory findings. Future studies could extend this induction approach to further dysfunctional and functional attention foci.