The effects of dream rebound: evidence for emotion-processing theories of dreaming.

Suppressing thoughts often leads to a "rebound" effect, both in waking cognition (thoughts) and in sleep cognition (dreams). Rebound may be influenced by the valence of the suppressed thought, but there is currently no research on the effects of valence on dream rebound. Further, the effects of dream rebound on subsequent emotional response to a suppressed thought have not been studied before. The present experiment aimed to investigate whether emotional valence of a suppressed thought affects dream rebound, and whether dream rebound subsequently influences subjective emotional response to the suppressed thought. Participants (N = 77) were randomly assigned to a pleasant or unpleasant thought suppression condition, suppressed their target thought for 5 min pre-sleep every evening, reported the extent to which they successfully suppressed the thought, and reported their dreams every morning for 7 days. It was found that unpleasant thoughts were more prone to dream rebound than pleasant thoughts. There was no effect of valence on the success or failure of suppression during wakefulness. Dream rebound and successful suppression were each found to have beneficial effects for subjective emotional response to both pleasant and unpleasant thoughts. The results may lend support for an emotion-processing theory of dream function.