Dream affect : conceptual and methodological issues in the study of emotions and moods experienced in dreams

We experience affect—emotions and mood—not only when we are awake but also during dreaming. Despite considerable research, existing theories and empirical findings disagree about the frequency, nature, and correlates of dream affect. In this thesis, I discuss the conceptual and methodological issues that underlie these discrepancies. I present five empirical studies, the overall aim of which was to investigate the phenomenology and correlates of dream affect and how results regarding these are influenced by study methodology. Studies I–III focused specifically on methodological issues, by comparing self- and external ratings of dream affect (Studies I–II) or the affective content of home and laboratory dream reports (Study III). Studies IV and V investigated the waking well-being and neural correlates of dream affect, respectively. These studies show that results and conclusions regarding dream affect are very different, even contradictory, depending on whether dream reports have been collected using sleep laboratory awakenings or home dream diaries (Study III) or whether dream affect has been measured using self- or external ratings (Studies I–II). Self- and external ratings of dream affect are also differently correlated with waking well-being (Study IV). Together, these results caution against making broad generalizations about affective dream experiences from findings obtained with one type of methodology only. The studies also demonstrate that dream affect is related to aspects of waking well-being and ill-being (Study IV) and that certain affective states experienced in dreams, specifically anger, rely on similar neural processes as in wakefulness (Study V). These findings suggest that the phenomenology and neural correlates of affective experiences are, at least to some extent, continuous across sleep and wakefulness. Overall, this thesis shows how the conceptual and methodological issues in the study of dream affect may limit the validity, generalizability, and replicability of findings and, consequently, pose challenges to theory building and theory testing. It contributes to dream research by highlighting the need, and suggesting ways, to enhance the conceptual clarity and methodological rigour of research on dream affect. Due to the interdisciplinary nature of the thesis, the theoretical discussion and novel empirical findings also have implications for emotion research, sleep research, well-being research, consciousness research, and affective neuroscience