Keeping a logbook tends to enhance dream recall

Dream recall is underestimated by retrospective measures but enhanced by logbooks, according to research published in Consciousness and Cognition.

Retrospective measures involve asking participants to estimate how often they can recall their dreams. Logbooks, on the other hand, require participants to keep a daily record of one’s dreams.

The new study helps explain why past research on dream recall has resulted in inconsistent findings.

PsyPost interviewed the study’s author, Denholm J. Aspy of the University of Adelaide. Read his responses below:

PsyPost: Why were you interested in this topic?

Aspy: My interest in the measurement of dream recall is related to my primary research focus, which is lucid dream induction. A lucid dream is a dream in which the dreamer is aware that they are dreaming while the dream is still happening. Lucid dreaming has a wide range of potential benefits and applications. This includes applications in scientific dream research, improvement of skills through rehearsal in the lucid dream environment, the use of lucid dreaming for treating nightmares, lucid dream recreation for people who are limited in their ability to have enjoyable experiences while awake (e.g. due to disability or remote work locations), and the use of lucid dreaming for problem solving and creative inspiration. Lucid dreaming is a learnable skill and a wide range of techniques for inducing lucid dreams have been developed. Numerous empirical studies have been conducted on lucid dream induction.

However, none of the techniques studied have been shown to be highly effective or reliable. Furthermore, the empirical literature on lucid dream induction suffers a wide range of limitations. One of these limitations in the literature is inconsistent operationalisation of lucid dreaming rates, which makes it very difficult to compare the findings of different studies and get an overall sense of how effective the different techniques are. Therefore, more methodologically rigorous research on lucid dream induction is needed, and this needs to include more research on the valid measurement of dream recall measures.

While I was preparing experiment materials for my own lucid dream induction research, I noticed that there are many issues in the wider literature on dream recall. In particular, I noticed that retrospective measures of dream recall (which involve participants reporting their dream recall in the recent past in response to a single question) tended to yield substantially lower dream recall rates than logbook measures (which involve reporting one’s dream recall each morning using a logbook). I called this phenomenon the retrospective-logbook disparity. This phenomenon raises important questions about the valid measurement of dream recall, which I addressed in detail in a review paper that was published in 2015. My empirical study on dream recall published in 2016 followed up on this review paper and addressed many of the questions that were raised.

Based on this study, a range of recommendations for the valid measurement of dream recall were provided. The study also presented a novel logbook measure of dream recall, which operationalises dream recall as Dream Quantity (DQ). This measure involves rating each individual dream for the amount of content recalled, and provides an overall measure of how much dream recall there is each morning. DQ provides a more sensitive measure of dream recall than the more commonly used operationalisations known as Dream Recall Frequency (the percentage of days in a given period on which any amount of dream content was recalled) and Dream Count (the number of separate dreams recalled each morning). By conducting this study, I was able to use the DQ measure in subsequent research on lucid dream induction. This research was conducted using a large national sample of Australian residents (N = 169) and is currently being considered for publication by a leading peer-reviewed academic journal.

What should the average person take away from your study?

What the average person can take away from this study is that it is extremely important to ensure that scientific studies use measures that are valid and reliable. Many different measures of dream recall have been used in previous studies, and many of these measures appear to be unreliable or invalid. This casts doubt on much of the existing empirical literature on dream recall, and may explain why there are so many mixed findings and failures to replicate previous studies in the literature. Hopefully, my 2015 and 2016 papers will help researchers to re-evaluate this literature and help future researchers maximize the validity of the dream recall measures they use in future studies.

The study was titled: “Is dream recall underestimated by retrospective measures and enhanced by keeping a logbook? An empirical investigation“.