Dream affect - Pilleriin Sikka - DiVA Portal (PDF)

Pilleriin Sikka B 506 ANNALES UNIVERSITATIS TURKUENSIS ISBN 978-951-29-7938-7 (PRINT) ISBN 978-951-29-7939-4 (PDF) ISSN 0082-6987 (Print) ISSN 2343-3191 (Online) Painosalama Oy, Turku, Finland 2020 TURUN YLIOPISTON JULKAISUJA – ANNALES UNIVERSITATIS TURKUENSIS SARJA - SER. B OSA - TOM. 506 | HUMANIORA | TURKU 2020 DREAM AFFECT: Conceptual and Methodological Issues in the Study of Emotions and Moods Experienced in Dreams Pilleriin Sikka   1 DREAM AFFECT: Conceptual and Methodological Issues in the Study of Emotions and Moods Experienced in Dreams Pilleriin Sikka TURUN YLIOPISTON JULKAISUJA – ANNALES UNIVERSITATIS TURKUENSIS SARJA - SER. B OSA - TOM. 506 | HUMANIORA | TURKU 2020  University of Turku Faculty of Social Sciences Department of Psychology and Speech-Language Pathology Turku Brain and Mind Center Doctoral Programme in Clinical Research Supervised by Professor Antti Revonsuo Department of Psychology and Speech-Language Pathology University of Turku Turku, Finland Docent Katja Valli Department of Psychology and Speech-Language Pathology University of Turku Turku, Finland Reviewed by Professor Antonio Zadra Department of Psychology Université de Montréal Montréal, Canada Professor Tracey Kahan Department of Psychology Santa Clara University Santa Clara, CA, US Opponent Professor Antonio Zadra Department of Psychology Université de Montréal Montréal, Canada The originality of this publication has been checked in accordance with the University of Turku quality assurance system using the Turnitin OriginalityCheck service. Cover Image: Pilleriin Sikka (with the help of Pixabay) ISBN 978-951-29-7938-7 (PRINT) ISBN 978-951-29-7939-4 (PDF) ISSN 0082-6987 (Painettu/Print) ISSN 2343-3191 (Sähköinen/Online) Painosalama Oy, Turku, Finland 2020  I had a dream...  4 UNIVERSITY OF TURKU Faculty of Social Sciences Department of Psychology and Speech-Language Pathology Pilleriin Sikka: Dream affect: Conceptual and Methodological Issues in the Study of Emotions and Moods Experienced in Dreams Doctoral Dissertation, 136 pp. Doctoral Programme in Clinical Research January 2020 Abstract 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. KEYWORDS: dreaming, affect, emotions, self-ratings, external ratings, REM sleep, well-being, peace of mind, frontal alpha asymmetry  5 TURUN YLIOPISTO Yhteiskuntatieteellinen tiedekunta Psykologian ja logopedian laitos Pilleriin Sikka: Tunnetilat unissa: käsitteelliset ja metodologiset haasteet unissa koettujen tunteiden ja mielialojen tutkimuksessa Väitöskirja, 136 s. Turun kliininen tohtoriohjelma Tammikuu 2020 Tiivistelmä Koemme tunnetiloja – tunteita ja mielialoja – sekä valvetilassa että unennäön aikana. Tämän väitöskirjan tavoitteena on selvittää, miksi unissa esiintyviä tunnetiloja koskevat teoriat ja aikaisemmat tutkimustulokset ovat ristiriitaisia. Väitöskirjan tutkimuksissa analysoidaan erityisesti erilaisten käsitteellisten määritelmien sekä erilaisten aineistonkeruu- ja analyysimenetelmien vaikutusta unennäön tunnetiloista saatuihin tuloksiin. Väitöskirja koostuu viidestä osatyöstä, joiden tarkoituksena oli selvittää unissa esiintyvien tunnetilojen yleisyyttä, luonnetta ja hermostollisia vastineita sekä tarkastella erilaisten tutkimusmenetelmävalintojen vaikutusta tuloksiin. Tutkimuksissa I–III keskityttiin menetelmävalintojen vaikutuksiin: Tutkimuksissa I– II vertailtiin itsearviointien ja ulkoisten arviointien vaikutusta unien tunnesisältötuloksiin, kun taas tutkimuksessa III tarkasteltiin tutkimusympäristön, jossa uniraportit kerättiin, vaikutusta unien tunnesisältötuloksiin. Tutkimuksessa IV keskityttiin unissa esiintyvien tunteiden ja hyvinvoinnin väliseen suhteeseen ja tutkimuksessa V unien tunnetilojen hermostollisiin korrelaatteihin. Tutkimukset I–III osoittavat, että tulokset ja johtopäätökset ovat huomattavan erilaisia, jopa ristiriitaisia, riippuen siitä, onko unien tunnetilat arvioinut unennäkijä itse vai ulkoinen arvioija (tutkimukset I–II) ja onko unet raportoitu kotona vai unilaboratoriossa (tutkimus III). Tutkimus IV paljasti unissa koettujen tunnetilojen olevan yhteydessä valveilla koettuun hyvinvointiin ja tutkimus V osoitti, että unissa ja valveilla koetut tunnetilat, erityisesti vihaisuuden tunne, perustuvat samanlaisiin hermostollisiin prosesseihin. Väitöskirjan tulokset osoittavat, että unissa esiintyviä tunnetiloja koskevat tutkimukset eivät ole aikaisemmin tuottaneet yhteneviä tuloksia ilmeisesti siksi, että eri tutkimuksissa on käytetty erilaisia käsitteellisiä määritelmiä sekä erilaisia aineistonkeruu- ja analyysimenetelmiä. Erilaiset määritelmät ja tutkimusmenetelmät väistämättä johtavat epäyhtenäisiin tutkimustuloksiin. Täten yksittäisten tutkimusten yleistettävyys ja toistettavuus on hyvin rajallista, eikä niiden perusteella ole mahdollista kehittää tai luotettavasti testata teorioita unennäön aikaisista tunnetiloista. Tämä väitöskirja edistää unennäön tunnetilojen tieteellistä tutkimusta osoittamalla, että tutkimusalueen käsitteellistä ja menetelmällistä perustaa on huomattavasti selkeytettävä, jotta tutkimukset tuottaisivat luotettavia, yleistettäviä ja yhteneviä tuloksia. Väitöskirjassa esitetään useita konkreettisia ehdotuksia, miten tutkimusaluetta olisi tähän suuntaan kehitettävä. Väitöskirjan tulokset ja johtopäätökset eivät rajoitu koskemaan pelkästään unennäön tutkimusta, vaan ovat merkityksellisiä myös laajemmin tajunnantutkimuksessa, subjektiivisen hyvinvoinnin tutkimuksessa ja tunnetilojen biologista perustaa tutkivassa neurotieteessä. ASIASANAT: unennäkö, tunnetilat, tunteet, itsearvio, ulkoinen arvio, REM uni, hyvinvointi, mielenrauha, frontaalinen alfa-asymmetria  6 Acknowledgements To paraphrase the well-known saying, this PhD was only made possible by standing on the shoulders of giants. Here is my chance to shine the light onto them. Over the years I have crossed paths with so many of these giants, so I take the opportunity to apologize upfront to all of those who I might unintentionally leave in the shadows. My heartfelt gratitude goes, first and foremost, to my supervisors Professor Antti Revonsuo and Docent Katja Valli. It is Antti who invited me to join his Consciousness Research Group at the University of Turku and who introduced me to the science of altered and higher states of consciousness—dreaming, hypnosis, and happiness research—well before I even contemplated doctoral studies. Our looooong discussion on life, the universe, and everything (about the brain) began in his office on a dark winter morning many, many years ago and has, over time, extended all the way to Sweden. Antti is an unlikely mix of Professor Dumbledore and Harry Potter: wise and (com)passionate, calm and collected, humble and humorous (I have laughed to the point of not being able to speak); and a visionary, with the magical ability to build bridges (across different fields) and untangle webs of knowledge. He asks exactly the right critical questions and comments on that one thing that one wishes one could ignore, but which, if left unaddressed, would prove to be the Achilles’ heel. He has given me the time and space to explore my own interests, wander along the routes I have chosen and helped me get back on track when I have felt lost or stuck (and there have been quite a few of those occasions). Antti is the epitome of Stoic values, and I have learned (and am still learning) from him how to peacefully but persistently tread the academic path. Antti, you are a science wizard and a mentor in the best sense of the words—thank you for showing me what it means to be a Scientist and a Teacher! Katja introduced me to the nuts and bolts of sleep and dream research: how to perform polysomnographic recordings, score sleep stages, collect and analyse dream reports. She leads by example; being hardworking and having incredible multi- tasking abilities, she is always everywhere and doing everything, yet ready to answer an email as soon as it pops into her mailbox or run to the lab as soon as she is called for. A true academic firefighter and paramedic in one, she has solved many emergencies. Katja has an eye for details and an answer to every question…at least to all of those involving sleep, dreaming, and evolutionary psychology. She makes the impossible possible—organizing our research group seminars and getting everyone into one room at the same time is a true feat (and her amazing coffee brewing ability forms only a small part of it). She has made the university a cosy place to be; seeing Katja in her woollen socks sliding along the floors and searching for her dog Amor (our past resident mood-booster) makes one feel immediately at  7 home. Katja, thank you for all your time and energy, for being so responsive, for all the detailed comments on manuscripts and for the immensely encouraging words. I am incredibly lucky to have had several mentors in my academic life who have shaped me both as a researcher and a person. Professor Talis Bachmann (University of Tartu, Estonia) was my first ever supervisor (when I was still an undergraduate) and it is he who helped kindle my love of research in general, and of consciousness research in particular. I am happy that he saw enough potential in a young and naïve student to take on the challenge of showing me what basic research is all about (it is quite likely I would have ended up as a sports psychologist otherwise). He took me under his protective wing from day one and has supported (and fought for me) ever since. He is also the reason why I ended up in Antti’s research group in Turku, and as such, is directly responsible for me having done my PhD here. Talis, I am deeply grateful for everything you have done for me! Dr Philip Burnet (University of Oxford, UK) chose me as his research assistant to work on a project in a field I knew virtually nothing about. “Ah, you’ll learn” was his answer to my concerns, and he was right—thanks to him I discovered that I really can learn to do things that, at first glance, seem beyond me. This piece of self- knowledge and -belief has helped me immensely during my PhD. Phil also showed me that life in a research laboratory can be utterly fun and “iiiiiinteresting” every single day, and that kindness and teamwork are the necessary ingredients of a successful and happy research environment. I am very grateful to the reviewers of this thesis, Professor Antonio Zadra and Professor Tracey Kahan, for having taken the time (amidst their tight schedules, no doubt) to provide extremely detailed, insightful, and encouraging feedback. A special thank-you to Professor Zadra for agreeing to serve as an opponent at my public defence (and for being willing to suffer the inevitable jet lag this will cause). It is my honour to share the stage and engage in a scientific discussion on the topic of my PhD with such an esteemed expert in the field of sleep and dream research. I also take the opportunity to thank all the reviewers of my publications for their encouragement and constructive criticism, the sleep and dream researchers I have had the opportunity to meet in person and whose reassuring words have made all the difference, and the whole dream/sleep/emotion/consciousness/wellbeing research community for their constant inspiration (and perspiration in trying to keep up with the latest developments). As part of this PhD, I have been fortunate to collaborate with several talented researchers within and outside our research group who directly (as co-authors), as well as indirectly, have contributed to the successful completion of this work: Dr Valdas Noreika (now at the University of Cambridge, UK), Dr Henri Pesonen (now at the University of Oslo, Norway), Dr Nils Sandman (University of Turku) and Jarno Tuominen (University of Turku).  8 Valdas (the gentle EEG giant) has been of invaluable help in countless ways: from the practical how-to-analyse-EEG-data to the more general how-to-make-wise- academic-(and-life)-decisions. Like a good daemon by one’s side, he always appears at the right moment, whispers advice in your ear, and gives you a friendly push in the right direction. Without him, Study V would still be in the drawer—thank you, Valdas, for making sure I have this cherry on my PhD cake! His perspective, patience, kindness, and autonomy-supportive mentoring style will make him an ideal PI of his own future research group. I am also grateful to his lovely wife Audrone Noreikiene, and their children Emilija and Linas, for their warmth and hospitality— thank you for making me feel so welcome when I first arrived in Turku and once again in Cambridge. Henri P. (the stats wizard) lent a helping hand (and brain) when I was frantically searching for a statistics expert to ask for advice on analyses for Study IV. Despite having a long queue of advice-seekers and being overloaded with various research projects, his door and mailbox were open, and he patiently responded to my never- ending flow of how and but why questions. Thank you, Henri, for not closing the door on me and for making my first landing in the R and multilevel modelling world so smooth. Nils (our own resident photographer and gastronome) content analysed the hundreds of dream reports for Studies I and III and provided extremely useful comments and much-needed support to proceed with Study III when things seemed a little difficult. Nils has also been the brain, body, and soul behind the PhD Shadow Seminars that, every once in a while, brought together all the PhD students to discuss important (and less important) empirical and philosophical matters. Thank you for having organized all those seminars—I learned a lot during these occasions. He is passionate about not only doing sleep research, but about using his knowledge to make a difference in the real world—this is truly inspiring! Jarno (a true Renaissance man) helped to content analyse the dream reports for Study III, though his role extends much further than that. He is a humble and bleeding-heart human(ist) with a constant hunger for new knowledge and skills (this must explain the reduced need for earthly food), an ability to look beyond borders and a need for combinatory play of ideas. Our intellectual (and non-intellectual) exchanges have given me new perspectives on science and life, adrenalin-rushes when conjuring up all-those-still-to-be-carried-out research ideas, the excitement of discovery (when entering his office and finding that new book to read), and a feeling of awe at the breadth and depth of his character. Jarno, thank you for the illumination! This PhD research would have not been possible without all the students and research assistants who helped collect and analyse the data for the studies. Diana Feilhauer, Tor Lehtonen, Teemu Paldanius, Linnéa Stenström, Lotta Sundelin, Tiina  9 Virta—thank you for your hard work and dedication, for the fun and fascinating discussions during data collection nights (these helped me stay awake and remain half-way sane). Diana, you went far beyond what was expected of you and were so enthusiastic and appreciative for every opportunity to learn more—thank you for being the best mentee one could wish for! I would also like to thank all the volunteers who participated in the studies—your dreams literally made my dream possible! A very special thank-you to my colleague and co-author Docent Sakari Kallio (the Mesmerist). He opened the door to the fascinating world of hypnosis research. Sakari’s passion toward the subject, my first-hand experience of being hypnotized and having witnessed the effects of post-hypnotic suggestions on a hypnotic virtuoso led me to study hypnosis at the University College London, UK. Over all those years, Sakari has been extremely supportive—first of my foray into the study of hypnosis, later as the Head of the Department of Cognitive Neuroscience and Philosophy at the University of Skövde, Sweden, with which I have been affiliated for as long as I have been in Turku. Sakari, thank you for the academic support, the opera lessons on the way to Skövde (which made me appreciate opera), and for the occasional live performance (it is mesmerizing)! I would like to express my sincere gratitude to Professor Jukka Hyönä and Professor Heikki Hämäläinen for providing a safe haven (in the form of the Department of Psychology and Speech-Language Pathology at the University of Turku) to carry out my PhD research. Thank you, Jukka, for always being so supportive and sympathetic. Jukka, together with Professor Lauri Nummenmaa, also taught me how to use eye-tracking. Lauri’s brain works at lightning speed on parallel tracks, with analyses, books, and papers pouring out accordingly, while always finding time for a friendly chat. Thank you! I am immensely grateful to all the other (past and present) members of our research group: Docent Valtteri Arstila—thank you for continuously educating me on the philosophy of mind, too bad that many of those lessons took place after several drinks; Simone Grassini—thank you for all the help with MATLAB, EEG, academia- and non-academia-related discussions, and for your contagious enthusiasm that makes one feel guilty of not being in the lab collecting data; Heidi Haanila—thank you for shedding light on the neurophilosophical perspectives of self-consciousness; Mikko Hurme—thank you for all those crazy gadgets you invented that brought joy into our hallway; Monika Intaité—thank you for discovering Turku with me; Roosa Kallionpää—thank you for always listening, for being so empathetic and caring and for all those heart-warming cards; Milla Karvonen—thank you for those lovely discussions in our shared office; Dr Mika Koivisto—thank you for all the advice regarding research design and analyses and for putting up with my non-stop chatter from which there is only one escape: the smoke sauna; Dr Levente Móró—thank you for all the IT help, the late-night  10 sandwiches, Indian food and the mind-expanding discussions on altered states of consciousness; Docent Henry Railo—thank you for your patience and for always finding time for me when I needed advice on anything, be it statistics, MATLAB, EEG analyses, you name it (all those PhD students and postdocs will be lucky to have you as the head of your own research group); Ville Rajala—thank you for being such a nice office mate; Dr Niina Salminen-Vaparanta—thank you for welcoming me to Turku, for organizing all our group seminar days, for teaching me how to do EEG recordings aeons ago and for discussions about life inside and outside academia; Gabriel Sjödin—thank you for always making me feel good about myself, for (re)introducing me to the Pooh and the Piglet, for helping me go the Way; and Dr Henri Olkoniemi (sorry for lumping you into our research group, though it surely does feel like you are one)—thank you for extending my vocabulary (sarcastic and not so sarcastic) during those long coffee breaks, for advice on multilevel modelling, and for warning me about all the last-minute PhD-related issues (you were so right)! A special thanks to the then-exchange students in our group—Marius Klug, Teddy Landron, Iris Bras, Angeliki Koukoura—you brought so much energy and enthusiasm, great ideas and insights, interesting discussions and fun; I am sorry for all the loooong dark winter days in Finland you had to endure. I am incredibly happy to have shared with you—dear members of our research group—all the movie evenings, fancy (and less fancy) dinners, serious fun (BBB aka Brains, Beers, and BBQ; EEE aka Eyes, Ethanol, and Entertainment), afterwork discussions on academia, consciousness, dreaming, predictive processing and everything else, laughter, dancing and so much more. Thank you for having put up with all those silly games and questions of mine! In addition to our research group, there have been many other individuals down the hall of the Department of Psychology at the University of Turku who have made all the difference. Suvi Holm, Anna Kautto, Sonja Kumlander, Myoung Soo Kwon, Oskari Lahtinen, Faramosh Rashid Izullah, Kati Renvall, Carina Saarela, Susanna Salomäki, Outi Tuomainen, Tiina Tuominen, Viktor Vorobyev—thank you for the intellectual and social stimulation! A special thanks to Teemu Laine (for the technical help), Maria Ek (for making administrative issues run so smoothly), and Vesa Rautio and Kristiina Nuutila (for taking care of all the doctoral programme- related matters)! I have spent half (or perhaps even more) of my PhD life on the other side of the Baltic Sea, at the Department of Cognitive Neuroscience and Philosophy, University of Skövde, Sweden. I am greatly indebted to our Skövde crew for being so supportive and tolerant of me jumping back and forth between Sweden and Finland. To Monica Bergman, Dr Stefan Berglund, Dr Daniel Broman, Kristoffer Ekman (Walsund), Docent Sakari Kallio, Dr Oskar MacGregor, Anders Milton, Dr Paavo Pylkkänen— thanks for being such a friendly group of people to share the academic world with. I  11 am especially grateful to Dr Björn Persson—thank you for not letting me be lost in the Swedish translation (this made it possible to carry out Studies II and IV), for the thought-provoking conversations in the doorway, and for keeping me abreast of the latest developments in research! I would like to thank Dr Tristan Bekinschtein for having had me as a visiting researcher in his Consciousness & Cognition Research Group at the University of Cambridge, UK. He and all the other members of the research group—Dr Anat Arzi, Alejandro Ezquerro Nassar, Barbara Jachs, Dr Daniel Bor, Dr Iulia Comsa, Maria Niedernhuber, Dr Sridhar Jagannathan—provided a fun and inspiring research environment to carry out the analyses for the final study of this thesis. Several foundations provided financial support for my PhD research: the Academy of Finland (grant to Antti Revonsuo), Alfred Kordelin Foundation, European Sleep Research Society, Finnish Cultural Foundation, Finnish Sleep Research Society, International Association for the Study of Dreams and Dream Science Foundation, Signe and Ane Gyllenberg Foundation, Turku University Foundation. I am deeply grateful! And, last but not least, I owe my warmest gratitude to my family, friends, and loved ones. Jan, thank you for the loving kindness, for helping me organize my thoughts, for being the best brainstormer and sparring partner, my pencil sharpener and eraser, and for dragging me out of my cave every now and then. I am sorry for all the suffering caused by having made you go through ‘a second PhD’ with me (it must be karma)! A huge thank-you to my parents: my mother Urve and my father Heikki. You have always believed in me, done everything in your power to support me and provided endless unconditional love. It is from you that I get the energy, persistence to not give up and the rebelliousness to go my own way. And, thank you to my brother Eero for being an inspiring example of performance and efficiency, love of learning and self-improvement. Aitäh teile kogu südamest! I am also extremely grateful to Anthonia and Alexander—thank you for always being so understanding (during all those times I was only half-present because of the PhD) and for celebrating every small step forward in the process. Tausend Dank! To all my friends who have seen me with the frequency of a solar eclipse—thank you for still being there! To my late lovely grandmother, who always wanted to know when I would finish studying—I’m afraid it is not the end. Thank you ALL for having been, and continuing to be, the giants on my Way…for this, I am forever grateful. Turku, December 2019 Pilleriin Sikka  12 Table of contents Acknowledgements .................................................................................. 6 Table of contents.................................................................................... 12 List of original publications ................................................................... 15 Abbreviations ......................................................................................... 16 1. Introduction ...................................................................................... 18 2. Conceptual foundation .................................................................... 20 2.1 What is consciousness? ............................................................. 20 2.2 What is a dream? ....................................................................... 22 2.3 What is affect? ............................................................................ 24 2.3.1 Affect: A conceptual map ................................................... 24 2.3.2 Models of affect ................................................................. 26 2.4 What is dream affect? ................................................................. 28 3. Methodological foundation ............................................................. 29 3.1 How dream experiences are studied: From experiences to retrospective self-reports ............................................................ 29 3.2 Methods for studying dream affect .............................................. 31 3.2.1 Typical methods for collecting retrospective self-reports of dream affect ...................................................................... 37 3.2.1.1 Sleep laboratory awakenings ................................ 37 3.2.1.2 Home dream diary................................................. 38 3.2.1.3 Most recent dream ................................................ 39 3.2.1.4 Dream questionnaire ............................................. 39 3.2.2 Typical methods for measuring dream affect ..................... 40 3.2.2.1 External ratings of dream affect............................. 40 3.2.2.2 Self-ratings of dream affect ................................... 41 4. Theoretical and empirical foundation ............................................. 44 4.1 Theories of dreaming: How and why we experience affect in dreams ....................................................................................... 44 4.1.1 Non-functional dream theories ........................................... 45 4.1.2 Functional dream theories ................................................. 47 4.2 Empirical literature on methodological issues ............................. 49  13 4.2.1 Self- versus external ratings of dream affect ....................... 49 4.2.2 Home versus laboratory studies of dream affect ................. 52 4.3 Empirical literature on the correlates of dream affect ................... 56 4.3.1 Dream affect and waking well-being ................................... 56 4.3.2 Neural correlates of dream affect ....................................... 58 5. Aims of empirical studies ................................................................ 62 6. Methods ............................................................................................. 64 6.1 Participants ................................................................................. 64 6.2 Procedure .................................................................................... 64 6.3 Measurements ............................................................................. 68 6.3.1 Home dream diary .............................................................. 68 6.3.2 Measurement of dream affect ............................................. 69 6.3.2.1 Self-ratings of dream affect .................................... 69 6.3.2.2 External ratings of dream affect ............................. 70 6.3.2.3 Dream affect variables ........................................... 72 6.3.3 Measurement of waking well-being .................................... 72 6.3.4 Polysomnography/Electroencephalography ........................ 73 6.4 Statistical analyses ...................................................................... 73 7. Results .............................................................................................. 76 7.1 Phenomenology of dream affect: Impact of study methodology ... 76 7.1.1 Comparison of self- and external ratings of dream affect .... 76 7.1.2 Comparison of home and laboratory dream reports ............ 81 7.2 Correlates of dream affect ........................................................... 83 7.2.1 Dream affect and waking well-being ................................... 83 7.2.2 Dream affect and frontal alpha asymmetry ......................... 84 8. Discussion ........................................................................................ 87 8.1 Phenomenology of dream affect: Impact of study methodology ... 87 8.1.1 Self- versus external ratings of dream affect ....................... 87 8.1.2 Dream affect in home versus laboratory dream reports ...... 93 8.2 Correlates of dream affect ........................................................... 95 8.2.1 Dream affect and waking well-being ................................... 95 8.2.2 Neural correlates of dream affect ........................................ 97