A team of international researchers including Pilleriin Sikka, Katja Valli, and Antti Revonsuo have published an article in the journal Consciousness and Cognition entitled “I know how you felt last night, or do I? Self- and external ratings of emotions in REM sleep dreams“.
The study investigated the difference between self-reports and external ratings of emotions in reported dreams, and found that external ratings tended to rate fewer positive emotions than self-reports.