Is dream recall underestimated by retrospective measures and enhanced by keeping a logbook? A review

Sleep and dreaming in the light of reactive and predictive homeostasis

Dreams are often viewed as fascinating but irrelevant mental epihenomena of the sleeping mind with questionable functional relevance. Despite long hours of oneiric activity, and high individual differences in dream recall, dreams are lost into oblivion. Here, we conceptualize dreaming and dream amnesia as inherent aspects of the reactive and predictive homeostatic functions of sleep. Mental activity during sleep conforms to the interplay of restorative processes and future anticipation, and particularly during the second half of the night, it unfolds as a special form of non-constrained, self-referent, and future-oriented cognitive process. Awakening facilitates constrained, goal-directed prospection that competes for shared neural resources with dream production and dream recall, and contributes to dream amnesia. We present the neurophysiological aspects of reactive and predictive homeostasis during sleep, highlighting the putative role of cortisol in predictive homeostasis and forgetting dreams. The theoretical and methodological aspects of our proposal are discussed in relation to the study of dreaming, dream recall, and sleep-related cognitive processes.

Dream Recall Frequency, Lucid Dream Frequency, and Personality During the Covid-19 Pandemic

Dream recall frequency and lucid dream frequency showed large inter-individual differences that are partly related to personality dimensions. However, as dream research is a small field, independent studies are necessary to build a solid empirical foundation. The present online survey included 1,537 participants (1150 women, 387 men) with a mean age of 35.1 ± 15.8 years. Whereas the relationship between openness to experience and dream recall frequency was in line with previous research - supporting the life-style hypothesis of dream recall, the associations between the Big Five personality factors and lucid dream frequency are less homogenous; for example, the negative relationship between neuroticism and lucid dream frequency. Even though the effect sizes of these associations are small, the findings can help in identifying links between waking and dreaming. Moreover, it was found that lucid dream frequency was related to Covid-19-related worries, whereas dream recall frequency was not.

An observatory on changes in dreaming during a pandemic: a living systematic review (part 1)

A 'new' way of dreaming has emerged during the pandemic, enhancing the interest of psychological literature. Indeed, during the years of the spread of coronavirus disease 2019 (COVID-19), many studies have investigated dream-related phenomena and dreaming functions. Considering the constant and rapid emergence of new results on this topic, the main aim of this study was to create an 'observatory' on the short- and long-term consequences of the COVID-19 pandemic on dreaming, by means of a living systematic review. The baseline results are presented, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guidelines, to identify and discuss existing studies about dreams and dreaming during the COVID-19 pandemic published until February 2022. Web of Science, Embase, EBSCO, and PubMed were used for the search strategy, yielding 71 eligible papers included in the review. Our results show: (a) a more intense oneiric activity during lockdown; (b) changes in dreaming components (especially dream-recall and nightmare frequency); (c) a particular dreaming scenario ('pandemic dreams'); (d) an alteration of the dreaming-waking-life continuum and a specific function of dreaming as emotional regulator. Findings suggest that monitoring changes in dreaming provides important information about psychological health and could also contribute to the debate on the difficulties of dreaming, as well as sleeping, in particular during and after a period of 'collective trauma'.

Dreaming and Sleep-Related Metacognitions in Patients with Sleep Disorders

Sleep-related metacognitions play a role in the etiology of insomnia and are distressing while falling asleep. Although similar concepts, such as thought suppression, have been studied in the context of dreaming, the relationship between sleep-related metacognitions and more negatively toned dreaming due to stressful pre-sleep experiences has yet to be studied. Overall, 919 patients with various sleep disorders completed the Metacognitions Questionnaire-Insomnia (MCQ-I20), Arousal Disposition Scale (APS), and Pre-Sleep Arousal Scale (PSAS) and kept a sleep diary over seven days eliciting dream recall, nightmare frequency, and the emotional tone of their dreams. The regression analysis showed that the MCQ-I20 (small effect size) and the APS (medium effect size) were associated with nightmare frequency and negatively toned dream emotions. These findings suggest that dysfunctional sleep-related metacognitions that are active prior to sleep are also associated with more negatively toned dreaming and more nightmares—even after controlling for trait arousability. It would be very interesting to study where therapeutic strategies, such as metacognitive therapy explicitly targeting sleep-related metacognition, could also be beneficial with regard to dreams (more positive dreams and fewer nightmares).

The route to recall a dream: theoretical considerations and methodological implications

The goal of this paper is to shed new light on the relation between dream recall and dream experiences by providing a thorough analysis of the process that leads to dream reports. Three crucial steps of this process will be distinguished: dream production (the generation of a conscious experience during sleep), dream encoding (storing a trace of this experience in memory) and dream retrieval (accessing the memory trace upon awakening). The first part of the paper will assess how major theories think about the relationship between dream reports and these distinct steps. The second part will systematise how trait and state factors affecting dream recall-given different theoretical assumptions-might interact with dream production, encoding and retrieval. Understanding how the distinct steps of dream recall can be modulated by different factors is crucial for getting a better grip on how to acquire information about these steps empirically and for drawing methodological conclusions with regard to the tools dream research relies on to collect subjective data about dream experiences. The third part of the paper will analyse how laboratory reports, logs and retrospective scales interact with the different factors that affect the distinct steps leading to dream reports and will argue that prospective methods provide more direct access to data regarding dream production and encoding than retrospective methods, which-due to their inability to provide systematic control over the factors affecting the retrieval stage-screen-off the variability in the production and the encoding of dreams.

Olfaction-Related Factors Affecting Chemosensory Dream Content in a Sleep Laboratory

Mental activity in sleep often involves visual and auditory content. Chemosensory (olfactory and gustatory) experiences are less common and underexplored. The aim of the study was to identify olfaction-related factors that may affect the occurrence of chemosensory dream content. Specifically, we investigated the effects of all-night exposure to an ambient odour, participants' appraisal of their current olfactory environment, their general propensity to notice odours and act on them (i.e., odour awareness), and their olfactory acuity. Sixty pre-screened healthy young adults underwent olfactory assessment, completed a measure of odour awareness, and spent three nights in weekly intervals in a sleep laboratory. The purpose of the first visit was to adapt to the experimental setting. On the second visit, half of them were exposed to the smell of vanillin or thioglycolic acid and the other half to an odourless control condition. On the third visit, they received control or stimulation in a balanced order. On each visit, data were collected twice: once from the first rapid eye movement (REM) stage that occurred after 3 a.m., and then shortly before getting up, usually from a non-REM stage. Participants were asked to report the presence of sensory dream content and to assess their current olfactory environment. Neither exposure, nor participants' assessments of the ambient odour, or olfactory acuity affected reports of chemosensory dream content but they were more frequent in individuals with greater odour awareness. This finding may have implications for treatment when such experiences become unwanted or bothersome.

Assessment of dream-related aspects and beliefs in a large cohort of French students using a validated French version of the Mannheim Dream questionnaire

Focusing on a specific population when studying dream characteristics can shed light on underlying mechanisms and correlates of dreaming. The aim of this study is to establish a clearer description of specific dream aspects and beliefs in a large cohort of students using a validated questionnaire, and to further investigate the role of sociodemographic variables such as age, gender and field of study. Participants were 1137 students aged from 18 to 34 (mean age: 22.2) who responded to an online version of the questionnaire. Our results showed a difference between humanities and science students, and a differential effect of gender on dream variables. Our results are discussed in light of previous investigations using the same questionnaire or focusing on the same population.

Assessing Individual Differences in the Affective Experience of Dreams: The Jena Dream Inventory–Affect Scales (JeDI-A)

The study reports on the validation of a new instrument for the assessment of emotional experiences in dreams. The Jena Dream Inventory–Affect (JeDI-A) contains 21 items and 3 scales, positive dream affect, negative dream affect, and dream intensity, providing a differentiated yet economic assessment of dream affect. Cross-sectional and longitudinal analyses in a sample of university students ( N = 426) and a clinical sample of patients with sleep disorders ( N = 149) supported factorial validity and measurement invariance, high temporal stability (over 1 year and 9 months in the students and patients, respectively), convergent and discriminant validity regarding established measures of dream affect and the Big Five, and criterion validity regarding subjective well-being. Cross-lagged panel models showed reciprocal longitudinal effects between dream affect and waking affect. We conclude that the JeDI-A is a valid instrument for differentiated investigations of individual differences in dream affect in clinical and nonclinical populations.

Methodological Recommendations to Control for Factors Influencing Dream and Nightmare Recall in Clinical and Experimental Studies of Dreaming

In order to ensure robust relationships between the dependent and independent variables in clinical dream/nightmare studies, the major factors which influence the frequency of reported dreams must be controlled. This article sets out methodological recommendations to both researchers seeking to ensure the equivalence of experimental groups of participants in group-matching designs, and to clinicians who wish to check that any change in frequency of reported nightmares over the course of a psychological or a pharmacological intervention is not caused by factors other than the experimental treatment itself. The main factors influencing the frequency of dream recall are presented: demographic variables, psychological characteristics, pathological dimensions, and substance consumption. A series of questionnaires is proposed for easily measuring these control variables.

Dream Recall and Content versus the Menstrual Cycle: A Cross-Sectional Study in Healthy Women

The association between sleep and the menstrual cycle has been scarcely studied. This study aimed to investigate the association between dream recall and content and the menstrual cycle among a large sample of young women. To this aim, 944 women were asked about their day of menstrual cycle, whether they remembered the previous night’s dreams and if they did so to describe the dream content as pleasant or unpleasant. A total of 378 women recalled the previous nights’ dreams, with 199 reporting pleasant dream affect/content and 179 reporting unpleasant dream content. In women who recalled their dreams, there was an association of pleasant dream content with the luteal phase (p = 0.038). In conclusion, in women, the hormonal milieu of the luteal phase may influence dream content.

Investigating on the Methodology Effect When Evaluating Lucid Dream

Lucid dreaming (LD) is a state of consciousness in which the dreamer is aware that he or she is dreaming and can possibly control the content of his or her dream. To investigate the LD prevalence among different samples, researchers have used different types of methodologies. With regard to retrospective self-report questionnaire, two ways of proceeding seem to emerge. In one case, a definition of LD is given to participants (“During LD, one is–while dreaming–aware of the fact that one is dreaming. It is possible to deliberately wake up, to control the dream action, or to observe passively the course of the dream with this awareness”), while in the other instances, participants are presented separate questions targeting specific LD indicators (dream awareness and dream control). In the present study, we measured LD frequency in a sample of French student in order to investigate for possible disparities in LD frequency depending on the type of questionnaire as outlined above. Moreover, we also study links between the prevalence of LD as assessed, respectively, by each questionnaire with various factors such as Vividness of Mental Imagery and Parasomnia. Results revealed no significant difference between LD frequencies across questionnaires. For the questionnaire with definition (DefQuest), 81.05% of participants reported experience of LD once or more. Concerning the questionnaire based on LD indicators (AwarContQuest), 73.38% of participants reported having experienced LD once or more. However, with regard to the correlations analysis, links between LD prevalence and factors such as Vividness of Mental Imagery and Parasomnia, varied across questionnaires. This result is an argument suggesting that researchers should be careful when investigating links between LD and other factors. The type of methodology may influence findings on LD research. Further studies are needed to investigate on the methodology effect in LD research namely on the respective weight of awareness and control.

Is dream recall underestimated by retrospective measures and enhanced by keeping a logbook? An empirical investigation

In a recent review, Aspy, Delfabbro, and Proeve (2015) highlighted the tendency for retrospective measures of dream recall to yield substantially lower recall rates than logbook measures, a phenomenon they termed the retrospective-logbook disparity. One explanation for this phenomenon is that retrospective measures underestimate true dream recall. Another explanation is that keeping a logbook tends to enhance dream recall. The present study provides a thorough empirical investigation into the retrospective-logbook disparity using a range of retrospective and logbook measures and three different types of logbook. Retrospective-logbook disparities were correlated with a range of variables theoretically related to the retrospective underestimation effect, and retrospective-logbook disparities were greater among participants that reported improved dream recall during the logbook period. These findings indicate that dream recall is underestimated by retrospective measures and enhanced by keeping a logbook. Recommendations for the use of retrospective and logbook measures of dream recall are provided.