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ABSTRACT
Paradox of more sleep not resulting in increased dream recall
Mark Blagrove, PhD
Department of Psychology
University of Wales Swansea, SA2 8PP, UK.
m.t.blagrove@swansea.ac.uk
Mark Blagrove, Ph.D. is a member of the Department of Psychology
at the University of Wales. He is a lecturer and researcher on the
experimental psychology of sleep and dreaming, as well as being
past-president of ASD, a member of the editorial board of the Journal of
Sleep Research, and a consulting editor of the journal Dreaming.
Summary of Presentation
We know that long sleepers have approximately 50% more REM sleep than
short sleepers, that dreams are more likely to be reported from REM sleep
awakenings, and that dream report length increases with REM period length.
This study finds, however, that dream recall frequency is not greater in
long sleepers
Learning Objectives:
Attendees will learn about studies that have shown an association
between dreaming and REM sleep.
Attendees will learn about how individuals differ in terms of sleep
and dream measures.
Attendees will learn about the surprising result that individual
differences in sleep length are not associated with differences in dream
recall frequency or length of dreams.
Evaluation questions:
In what ways is REM sleep associated with the recall of dreams?
What measures can be made of differences between individuals in terms
of sleep and dream characteristics?
What explanations can be offered for the lack of association between
sleep length and dream recall frequency and dream length?
Abstract
Webb and Agnew (1970) found that people who sleep more than 8.5 hours
per night have approximately 50% more REM sleep than people who sleep
less than 6.5 hours. Stickgold et al (2001) found that 85% of awakenings
from REM sleep and 67% of awakenings from NREM sleep result in reports
with content, and that dream length (in words) of REM dreams increase
over the first 40 minutes of a REM period. It would thus be expected
that dream recall frequency and dream length would be greater in
individuals who sleep longer than in those who are short sleepers, a
result found by Baekeland and Hartmann (1971) but not confirmed by
Blagrove and Akehurst (2000). In the present study we assessed usual
sleep length, frequency of recalling dreams, frequency of telling dreams
to others, most recent dream emotional intensity/presence of
contextualizing image (CI), and length in words of most recent dream.
Questionnaires were analyzed from 671 adults (77% female, 23% male, mean
age = 33.0 years, SD=17.3). Sleep length had significant but small
correlations with frequency of dream recall (r=.11, p<.005) and dream
telling (r=,18, p<.001) but insignificant correlations with CI and
dream length. However, when age and sex were partialled out these
correlations with dream frequency became insignificant (r=.00 and r=.03
respectively). In contrast, with age and sex controlled for, the
personality trait openness to experience was significantly correlated
with DRF (r=.16, p<.001) and marginally dream telling frequency
(r=.08, p=.057). It remains somewhat a paradox that large individual
differences in sleep length, and this of REM sleep duration, do not
result in differences in dream recall or dream length. However, it may
be that the content of dreams from long sleepers may be different from
short sleepers, although, again, we did not find differences in
emotional intensity (CI) of dreams.
I acknowledge the financial and logistical support for this study
from the Chartered Institute for Library and Information Professionals,
and Frontiers: Science in Libraries, and the UK Science Year. I
acknowledge also the original idea from the (UK) Libraries Association
for investigating links between reading and dreaming.
Baekeland, F. & Hartmann, E. (1971). Reported sleep
characteristics: Effects of age, sleep length and psychiatric impairment.
Comprehensive Psychiatry, 12, 141-147.
Blagrove, M. & Akehurst, L. (2000). Personality and dream recall
frequency: further negative findings. Dreaming, 10, 139-148.
Stickgold, R., Malia, A., Fosse, R., Hobson, J.A. (2001). Brain-mind
states: I. Longitudinal field study of sleep/wake factors influencing
mentation report length. Sleep 24:171-179.
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