Content uploaded by Joseph De Koninck
All content in this area was uploaded by Joseph De Koninck on May 17, 2017
Content may be subject to copyright.
International Journal of Psychophysiology, 8 (1989) 43-41
Intensive language learning and increases in rapid eye movement
sleep: evidence of a performance factor
J. De Koninck, D. Lorrain, G. Christ, G. Proulx * and D. Coulombe
School of Psychology, University of Ottawa, Ottawa, Ont. (Canada)
(Accepted 2 August 1988)
Key words: Rapid eye movement sleep; Language learning; Information processing
Ten anglophone students taking a 6-week French immersion course were recorded in the sleep laboratory during 4 consecutive
nights before the course, during the course and after the course. There was a positive and significant (P < 0.05) correlation between
language learning efficiency and increases in the percentage of rapid eye movement (REM) sleep from pre-course to course periods.
This observation suggests that learning performance may be an important factor in the relationship between information processing
and REM sleep
It has long been proposed that rapid eye move-
ment (REM) sleep is involved in some form or
another in information processing and memory
(i.e. Jouvet, 1965; Empson and Clarke, 1970). A
leading notion formulated by Dewan (1970) and
labelled the ‘Programming Hypothesis’, proposes
that REM sleep is a process for setting up, or
programming, and constantly revising functional
structures in the brain, adjusting them to meet the
current needs of the organism. Such a process
would ensure consolidation of learning and pre-
pare for the assimilation of new information. An
alternative model was recently proposed by Crick
and Mitchinson (1983), suggesting that it is during
* Present address: Baycrest Hospital Department of Psy-
chology, North York (Toronto), Ont.. Canada.
Correspondence: J. De Koninck, School of Psychology, Univer-
sity of Ottawa, Ottawa, Ont. Canada, KIN 6N5.
REM sleep that ‘reverse learning’ or the elimina-
tion of problematic information which otherwise
compete with relevant material takes place. One
prediction consistent with both models is that
following intensive learning, organisms should ex-
hibit an increased need for REM sleep.
For more than 15 years, a host of studies have
tested this hypothesis and have been reviewed
periodically along with other predictions relating
REM sleep with information processing (i.e. Fish-
bein and Gutwein, 1977; McGrath and Cohen,
1978; Pearlman, 1979; Smith, 1985). While there
has been overall support, one interesting observa-
tion has emerged. In animals, increases in REM
sleep following learning tasks were related to
learning efficiency (cf. Leconte et al., 1973) and
not simply to the learning effort. Such a phenome-
non was not, however, clearly established in hu-
mans, although observations along those lines have
been made (Mandai et al., 1986: Verschoor and
Holdstock, 1984). We have now gathered data
from subjects involved in intensive language learn-
0167-X760/89/$03.50 0 1989 Elsevier Science Publishers B.V. (Biomedical Division)
ing which provide strong support for a relation-
ship between learning efficiency and increases in
REM sleep in humans.
Subjects and design
Ten subjects, 6 males and 4 females within an
age range from 18 to 28 years, participated in the
experiment. They were registered in a French Im-
mersion course at the University of Ottawa (de-
scribed below). Their first language was English
and their previous French language learning expe-
rience was limited to a secondary school level.
They received $10 for each night spent in the
French immersion course
Every summer, the University of Ottawa offers
a 6-week intensive French immersion course to
anglophone students. In addition to the courses,
students attend evening activities conducted en-
tirely in French. They spend weekdays in campus
residence. Such an environment provides an ideal
way to control learning conditions while maintain-
ing subjects in a ‘real-life’ situation. French pro-
ficiency is measured by a test developed at the
University of Ottawa. It has been used for 10
years and has proven to be a reliable and valid
measure of competence in French. It is adminis-
tered before the course and after the course thus
providing an assessment of learning efficiency.
Design and procedure
The experiment was conducted over 3 summers.
The first summer, 4 subjects were studied, the
second summer 2, and the last 4 during the third
summer. In each case, each subject spent a mini-
mum of 4 consecutive nights in the laboratory on
3 separate occasions (6 subjects were recorded for
two additional nights for dream collection). A
baseline series was run within two weeks before
the course. Subjects returned to the laboratory for
Series 2 within the second or third week of the
course. The last session was run within one month
after the end of the course. In each series, the first
two nights served as adaptation nights with data
collection on nights three and four.
Standard electrophysiological sleep measures
were recorded (Rechschaffen and Kales, 1968).
EEG was recorded from sites C3 and C4 with a
linked ear reference. EOG and EMG were re-
corded from bipolar montages. Electrode place-
ment followed the standard lo-20 International
system. The same sleep schedules were maintained
from one series of recordings to another. The
reliability of the sleep stage scoring was de-
termined by calculating the percentage of agree-
ment on 30-s sleep epochs from 6 full nights
between our main judge and that of another ‘blind’
judge. Better than 81% agreement was achieved
for all sleep parameters. For statistical analyses,
data for nights 3 and 4 of each series were com-
RESULTS AND DISCUSSION
Table I presents the distribution of sleep stage
percentages in the three conditions. Analyses of
variance revealed no difference for any of the
sleep stages. However, when the learning perfor-
mance of subjects was taken into account, a rela-
tionship between the percentage of REM sleep
and learning efficiency was observed. Table II
presents the detailed results of % REM and French
proficiency test scores for each subject. An analy-
sis of covariance using French improvement scores
(post-course minus pre-course scores) revealed a
significant increase in REM percentage from the
Distribution in mem percentuges of sleep stages ac’mss conditions
(nights 3 and 4 combined)
Wake 2.15 1.38 4.19
Stage 1 7.26 1.49 6.80
Stage 2 45.99 48.13 45.17
Slow wave sleep (3 + 4) 24.51 22.71 23.87
REM sleep 19.67 22.31 22.22
Distributron in sequence of REM percentages before, during and after the immersion course along n,rth scores on the French proficiency
Subjects Pre-course Pre-course
REM % French test Course
REM % Post-course
French test Post-course
1 24.43 II 21.45 85 21.28
2 20.39 46 25.16 55 14.97
3 24.46 38 24.38 41 25.27
4 24.21 36 19.67 36 22.94
5 13.37 56 25.75 69 21.47
6 17.05 48 28.97 66 28.86
7 20.45 25 23.40 46 22.35
8 18.85 68 21.60 78 22.30
9 15.35 20 17.15 35 20.55
10 18.00 63 8.20 67 22.25
pre-courseto the course period (F = 6.83, df = 1,8,
P < 0.03).
This relationship is clearly illustrated in Fig. 1.
This figure presents the distribution of REM per-
centages from pre-course to post-course for all of
the subjects along with their percentages of im-
provement in French proficiency (subjects’ graphs
are presented in order of level of French pro-
ficiency improvement). It can be seen that only
the last 3 subjects, with little (4% or less) or no
improvement in French, did not show increases in
REM % during the course. When only the 7 other
subjects who showed improvements in French were
considered, a repeated measures analysis of vari-
ance revealed a significant difference in REM %
across conditions (means respectively, 18.6, 24.3,
21.7, F,_,, = 4.35, P < 0.04). Trend analyses re-
vealed that the quadratic configuration (inverted
U) was the most significant ( F2,12 = 6.13, P <
0.05). In other words, efficient language learners
exhibited an increase in REM % during the course
and tended to return to baseline levels after the
course. Finally, another way of expressing this
relationship is the observation, for the total sam-
ple, of a significant Pearson product moment cor-
relation coefficient (r = 0.65, df = 8, P < 0.05) be-
tween learning progress and increases in REM %
from pre-course to course periods. However, the
correlation between learning progress and changes
in REM % from course to post-course was positive
but not significant (I = 0.28). An examination of
individual distributions (Fig. 1) suggests that this
is due to the maintenance of high REM % or even
further increases in some subjects (2, 3, 5).
Similar analyses performed on the other sleep
stages did not reveal any significant trend. It
appears then that the influence of intense lan-
guage learning is restricted solely to REM sleep.
Examination of individual records of the 7 sub-
jects who experienced REM % increases suggests
that stage 2 and/or slow wave sleep tended to be
reduced with a greater vulnerability for the latter
(4 subjects). These effects, however, were not sig-
These results are consistent with those obtained
in studies with animals and are a first clear con-
firmation of a performance factor in the relation-
ship between the amount of REM sleep and com-
plex learning. It will be important to further ex-
plore this phenomenon and to determine whether
our results are applicable to other types of human
learning, where performance varies widely be-
tween subjects. Future research may also de-
termine the influence of second language training
on interhemispheric EEG during sleep. There is
some controversy within the asymmetry literature
as to the localization of second languages (Paradis,
1987). Furthermore one theory of interhemi-
spheric relationships during sleep suggests that
REM is associated with greater right activation
while NREM sleep stages are said to involve left
hemisphere activation (Goldstein et al., 1972;
I’KE COUKSE POST
I’K I‘: COUKSE POST
I’KE COUKSE POST
io 1 COKDl~fION
PKE COtiKSE P&T I’KE COUKSE POST
I’KE COL’KSE POST I’KE C‘OL’KSE 1’05 I
Fig. 1. Distribution of REM percentages for each subject, presented in order of learning progress.
15 - I.~arn.pro~.
10 PKE CO~IKSE 1’0.‘; I’
10 0 I’KE CO~IKSE. I’OS I
I’KE COUKSE I’OS’I
Broughton, 1975). More recent studies have failed
to support this theory (cf. Armitage et al., 1988).
An evaluation of interhemispheric EEG changes
during French immersion may resolve some of
Supported by a grant from the Natural Scien-
ces and Engineering Research Council of Canada.
Armitage, R., Hoffmann, R., Loewy, D. and Moffit, A. (1988)
Variations in period-analysed EEG asymmetry in REM
and NREM sleep. Psychophysiology, in press.
Broughton, R. (1975) Biorythmic variations in consciousness
and psychological functions. Can. Psychol. Reo., 16 (4):
Crick, F. and Mitchinson, G. (1983) The function of dreams
sleep. Nature (Lo&), 304: 111-114.
Dewan, E.M. (1970) The programming (P) hypothesis for
REM sleep. In E. Hartmann (Ed.), Sleep and Dreaming,
Little, Brown and Company, Boston, pp. 295-307.
Empson, J.A.C. and Clarke, P.R.F. (1970) REM and remem-
bering. Nature (Land.), 227: 287-288.
Fishbein, W. and Gutwein, B.M. (1977) Paradoxical sleep and
memory storage processes. Behau. Biol., 19: 425-464.
Goldstein, L., Stoltzfus, N. and Gardocki, J. (1972) Changes in
interhemispheric amplitude relations in EEG during sleep.
Physiol. Behau., 8: 811-815.
Jouvet, M. (1965) Paradoxical sleep: a study of its nature and
mechanisms. Prog. Brain Rex, 18: 20-57.
Leconte, P., Hennevin, E. and Block, V. (1973) Analyse des
effets dun apprentissage et de son niveau d’acquisition sur
le sommeil paradoxal constcutif. Brain Res., 49: 367-379.
Mandai, I., Guerrien, A., Mouze-Amady, Sockell, P. and
Leconte P., REM Sleep Modifications ajter a Morse L.an-
guage Learning Session. Paper presented at the 8th European
Congress of Sleep Research, Szeged, Hungary, September
McGrath, M.J. and Cohen, D.B. (1978) REM sleep facilitation
of adaptive waking behavior: a review of the literature.
Psychol. Bull., 85 (1): 24-57.
Paradis, M. (1987) The Assessment of Bilingual Aphasia, Erl-
baum, Hillsdale, New Jersey.
Pearlman, C. (1979) REM sleep and information processing:
evidence from animal studies, Neurosci. Blobehau. Reu., 3:
Rechtschaffen, A. and Kales, A. (1968) A Manual of Standar-
dized Terminology, Techniques and Scoring System for Sleep
Stages of Human Subjects, Brain Information Service/Brain
Research Institute, University of California, Los Angeles,
Smith, C. (1985) Sleep states and learning: a review of the
animal literature. Neurosci. Biobehau. Reu., 9: 157-168.
Verschoor, G.J. and Holdstock, T.L. (1984) REM bursts and
REM sleep following visual and auditory learning. Sourh
Afr. J. Psychol., 14 (3): 69-74.