Journal of Abnormal Psychology
1967, Vol. 72, No. 3, 2SS-264
PSYCHOLOGICAL AND PHYSIOLOGICAL DIFFERENCES BETWEEN
GOOD AND POOR SLEEPERS 1
LAWRENCE J. MONROE 2
University of Chicago
Physiological, personality, and EEC sleep patterns of 16 Poor Sleep group
(PSG) Ss were compared with 16 Good Sleep group (GSG) Ss. Compared with
good sleepers, poor sleepers had less sleep time, a higher proportion of Stage 2
sleep, markedly less REM sleep despite a similar number of REM periods,
more awakenings, and required more time to fall asleep. Significant physiological differences between the groups were observed during all stages of sleep
and during a presleep period. Personality test results clearly indicated a much
higher probability of symptomatic complaints among poor sleepers as well as
a strong positive relationship between dreaming and indexes of psychopathology. This study did not resolve cause and effect relationships among
physiological variables, personality measures, amount of dreaming, and good
and poor sleep; however, significant EEG, physiological, and psychological
differences were demonstrated.
The resurgence of interest in sleep and
dream research during the past decade has
produced a considerable body of empirical
knowledge about both the psychology and
physiology of sleep and dreaming (see reviews
by Dement, 1965; Kamiya, 1961; Snyder,
1963). In light of this enhanced background
of empirical evidence, the time appeared ripe
to study psychological and physiological differences between good and poor sleepers. Although comments on qualitative aspects of
sleep have appeared in the clinical literature,
and articles have appeared in the popular
literature on the general topic of sleep disturbance, there is a very noticeable discrepancy between personal and social concern with
good and poor sleep and scientific concern
with this problem. This discrepancy is especially paradoxical in light of the rapid increase in the consumption of soporifics and
tranquilizers for sleep-inducement purposes
during the past decade.
Results of three preliminary questionnaire
investigations showed that people have definite impressions about whether they are
"good" or "poor" sleepers. These evaluations
appeared partially determined by how long it
usually takes to fall asleep, partly on subjective feelings of how "soundly" or "deeply"
one sleeps, and partly on how well rested one
feels on awakening. While there were other
idiosyncratic bases for the evaluation of how
1
Presented in part at the annual meeting of the well one sleeps, the above criteria were the
Association for the Psychophysiological Study of ones most frequently reported.
Sleep, Washington, D. C., March 196S, and based
These questionnaire studies clearly inupon a doctoral dissertation submitted to the Depart- dicated that individual indexes that could be
ment of Psychology, University of Chicago, in partial
fulfillment of the requirements for the degree of used to differentiate good and poor sleepers
Doctor of Philosophy. This research was supported were highly interrelated. Respondents who
by Public Health Service Grant MH-41S1 from the reported they fell asleep quickly also reNational Institute of Mental Health to Allan ported no difficulty in staying asleep, conRechtschaffen, and by an NIMH predoctoral Fellow- siderable enjoyment from sleep obtained, and
ship, No. 5 Fl-MH-20,726 to the author. The author
most of the time a feeling that they were well
wishes to express his gratitude to the members of
his dissertation committee: Allan Rechtschaffen rested in the morning. For subjects (5s) who
(chairman), Donald W. Fiske, and Salvatore R. reported a specific sleep problem, such as
Maddi. Special thanks are given to Gerald Vogel, difficulty in falling asleep, the probability
David Foulkes, Rosalind D. Cartwright, and Kay
was very high that additional sleep problems
J. Monroe for their invaluable aid and assistance.
2
Now at the University of Illinois College of would be reported, such as frequent awakenings, feeling tired or "worn out" in the mornMedicine.
255
LAWRENCE J. MONROE
256
TABLE 1
GOOD SLEEP GROUP (GSG) AND POOR SLEEP GROUP (PSG) RESPONSES TO SUBJECT
SELECTION-CRITERIA QUESTIONS
GSG
PSG
Subject selection questions
1 . How long to go asleep (min.) ?
2. How many times per week do you fall
asleep within 5 minutes?
3. How many times per week does it take
more than 30 minutes?
4. How many nights per week do you awaken
during the night?
5. How many times per night do you
wake up?
6. How many times per month do you wake
up and are unable to go back asleep?
7. When you awake how difficult is it to go
back to sleep?
No difficulty
Considerable difficulty
Usually not able to
Never able to
8. How much difficulty do you have in falling
asleep initially?
No difficulty
Very little difficulty
Quite a bit of difficulty
Much difficulty
9. How rested do you feel in A.M.?
Very rested
Moderately rested
Not very rested
Not rested at all
10. How much do you enjoy sleep?
Much enjoyment
Moderate enjoyment
Little enjoyment
No enjoyment
M
Mdn
Range
M
Mdn
Range
7.18
4.94
8
5
2-15
3-7
59.06
0.44
60
0
30-120
0-1
0.00
0
0
5.38
6
3-7
0.38
0
0-2
3.38
3
0-7
0.13
0
0-1
1.13
1
0-3
0.19
0
0-1
4.50
2
0-25
N
%
AT
%
16
0
0
0
100.0
7
3
5
1
43.7
18.7
31.3
13
3
0
0
81.3
18.7
0
3
12
1
18.7
75.0
6
9
1
0
37.5
56.3
4
7
5
0
25.0
43.7
31.3
7
8
1
0
43.8
50.0
1
10
4
1
62.5
25.0
ing, and, in general, a dissatisfaction with
their total sleep pattern. Thus, for purposes
of the present study, good sleepers were defined as persons who reported the following
sleep characteristics: (a) usually fall asleep in
less than 10 minutes but never more than IS
minutes; (b) as a rule, never wake up during
the night; and (c) as a rule, have no subjective difficulty in falling or remaining asleep.
The minimum requirements of poor sleepers
were that they report the following characteristics: (a) usually take 60 minutes or longer
to fall asleep and always more than 30 min-
0.0
0.0
0.0
0.0
0.0
6.2
0.0
6.2
0.0
6.3
0.0
6.3
0.0
6.2
6.3
utes; (6) usually wake up at least once during the night; and (c) usually experience
considerable subjective difficulty in falling
asleep, independently of how long it takes to
fall asleep.
Due to the paucity of empirical evidence on
what constitutes good and poor sleep, it
seemed most reasonable to initiate the investigation of good and poor sleepers in terms
of previously studied variables which have
been shown to vary systematically during
natural sleep. The results of numerous EEG
studies show considerable agreement regard-
257
GOOD VERSUS POOR SLEEPERS
TABLE 2
DIFFERENCES BETWEEN THE GSG AND PSG ON SLEEP-RELATED VARIABLES
GSG
PSG
Group differences
Sleep variable
Total sleep (min.)
Total time awake (min.)
Stage 2 sleep (min.)
Stage 2 (% sleep time)
Delta sleep (min.)
Delta (% sleep time)
REM sleep (min.)
REM sleep (% sleep time)
No. REM periods
Sleep prior to first REM period
No. REM awakenings
No. all awakenings
Time to sleep onset
M
SD
M
SD
M
t
388.56
31.44
188.28
48.32
105.03
27.34
95.25
24.34
4.00
91.59
0.69
2.31
7.38
29.37
29.34
32.84
6.72
19.54
6.40
23.00
5.43
1.27
56.15
1.10
1.61
6.95
346.47
73.53
191.00
54.86
97.34
28.20
58.72
16.93
3.44
111.84
1.50
3.88
15.16
60.63
60.64
47.12
10.59
32.81
9.75
22.74
5.75
1.11
62.95
1.06
1.83
15.82
42.09
42.09
2.72
6.54
7.69
0.86
36.53
7.42
0.56
20.25
0.81
1.56
7.78
2.37**
2.37**
0.24
2.53***
0.88
0.36
4.55*****
4.00****
1.09
1.02
1.89*
2.37**
1.81*
*t <.io.
**p <.OS.
*** p < .025.
**** p < .005.
***** p < .001.
ing the interaction of certain psychological
and physiological variables with variations in
the basic sleep cycle. The specific question
investigated was whether or not there were
measurable differences between good and poor
sleepers in sleep behaviors, in psychophysiological functioning, and in personality patterns.
METHOD
Subjects
The population of potential 5s was drawn from
a general university community. After having responded to an advertisement placed on local bulletin boards and in local newspapers, respondents
completed a questionnaire about their sleep habits.
On the basis of their responses to the criteria questions, respondents were classified into one of the
following categories of sleep quality: very good,
moderately good, moderately poor, or very poor.
Due to the skewed distribution of qualitative sleep
types, only 5s classified as "very good" were included in the final Good Sleep group (hereafter
referred to as the GSG); both "poor" and "moderately poor" sleep types were included in the final
Poor Sleep group (PSG). Table 1 shows the responses of the 16 GSG and the 16 PSG 5s to the
criteria questions. Although the two groups differed greatly in the self-reported evaluations of their
characteristic sleep patterns, the PSG cannot be
considered an extremely sleep-disturbed group; none
of the poor sleepers perceived themselves as "being
insomniacs" or as having any specific type of
sleep disturbance. In addition, all poor sleepers re-
ported that they usually slept at least 4 or S hours
per night without the aid of prescribed or commercial sleeping pills. While the PSG 5s were not
severely disturbed poor sleepers, they were substantially different from the GSG sample in their
subjective evaluation of sleep behaviors.
Each GSG 5 was matched with a PSG 5 on age,
education, and occupational classification. The mean
age of the GSG was 26.0 years, the median was
23.0 years, and the range was 20-40 years. The mean
age of the PSG was 25.3 years, the median was 24.0
years, and the range was 20-42 years. The mean
years of education for the GSG was 16.2, the median
was 16.5, and the range was 12-20 years. The mean
education of the PSG was 15.9 years, the median was
17.0, and the range was 8-18 years. While the modal
occupation for both groups was one of graduatestudent status, the range of occupations included
unskilled, skilled, semiprofessional, and professional
classifications. No 5 used in this study had any
previous experience as an experimental S in sleep
research.
Procedure
All 5s slept in the laboratory 2 nights under
essentially identical conditions; 1 or 2 nights of
nonlaboratory sleep intervened between the adaptation and the experimental night. The experimental
night consisted of a 30-minute presleep period and
a 7-hour sleep period; all physiological measures
were continuously monitored throughout both periods
using standardized recording techniques (Dement &
Kleitman, 1957; Rechtschaffen & Maron, 1964). Body
movements were detected by the use of a Piezoelectric crystal attached to the bedsprings and by
the EEG-artifact method of movement detection.
LAWRENCE J. MONROE
258
RESULTS
Sleep-Related Variables
All scoring of amount of time spent in the
various EEC-defined stages of sleep followed
standardized scoring procedures with the exception that Stages 3 and 4 were treated as
one stage and designated as Delta sleep. The
analysis of total sleep into various stages of
sleep produced some overlapping among the
different subclassifications of total sleep; in
addition, Stage 2, Delta, and rapid-eye-movement (REM) sleep variables were analyzed
both in terms of absolute minutes and percentages of total sleep spent in each stage.
Variables analyzed in the above ways were
interdependent rather than independent. The
statistical model used in testing the significance of group differences was the t test for
matched samples. Table 2 shows the results
obtained for sleep-related variables.
When the sleep cycle was considered as a
unit, the major differences in sleep patterns of
good and poor sleepers were accountable in
terms of differential proportions of Stage 2
and REM sleep. When sleep time by stages
was expressed as a percentage of total sleep,
the PSG averaged significantly more Stage
2 sleep (p < .025) and significantly less REM
sleep than the GSG (p < .005). The GSG had
62.2% more absolute minutes of REM sleep
and 43.8% more REM time when expressed
as the proportion of total sleep. In 15 of the
16 pairs of 5s, the good sleeper exceeded the
matched poor sleeper on amount and proportion of REM sleep; on the basis of the
binomial distribution, this finding was highly
significant (p < .001).
The groups did not differ significantly in
either the absolute amount of Delta sleep or
in the percentage of Delta sleep; however, a
difference was obtained in the distribution of
Delta sleep throughout the night. For the
PSG, 88.1% of their total Delta sleep occurred during the first half of the night compared to 71.6% of the total GSG Delta sleep.
During the last half of the night 28.4% of the
GSG total Delta sleep occurred, whereas only
11.9% of the PSG's Delta sleep occurred during the latter half of the night. Differences
between the groups in percentage of Delta
sleep in both halves of the night were significant at the .005 level.
The GSG spent 92.5% of the total bed
period in sleep compared with 82.5% for the
PSG. Although the groups differed significantly, this difference was not as marked as
the questionnaire data would have predicted.
An analysis of total awakenings by REM and
non-REM (NREM) stages showed that the
significant difference between the groups for
total number of awakenings was largely the
result of awakenings from REM periods. As
the two groups did not differ significantly in
the number of REM periods, the marked difference in REM time between the GSG and
PSG can be accounted for in terms of REM
periods of shorter duration and more frequent
REM awakenings for the PSG.
Physiological Measures
One-minute samples of physiological activity were obtained at 5-minute intervals
TABLE 3
PHYSIOLOGICAL DIFFERENCES BETWEEN THE GSG AND PSG DURING SLEEP
GSG
Rectal temperature (°F)
Vasoconstrictions/min
Body movements/hr j
Heart rate/min
,jj3
Pulse volume
Skin resistance (k ohms)
*t <.05.
**p <.025.
***f <.02.
Group differences
PSG
M
SD
M
so
97.22
0.84
5.76
56.64
29.76
126.48
.677
0.30
2.02
6.68
7.85
65.50
97.56
1.14
7.82
60.54
32.50
177.12
.375
0.39
2.92
6.97
6.75
76.70
Mom
.337
.30
2.06
3.90
2.74
50.64
(
2.68***
2.91***
2.25*
1.31
1.45
2.54**
GOOD VERSUS POOR SLEEPERS
259
V 9775
o
0 9750
9700 -
Tj
10
20
30
PRE-SLEEPIMIN)
3
4
SIEEP PERIOD IN HOURS
FIG. 1. Comparison of GSG and PSG on rectal temperature.
during the presleep period and at 10-minute
intervals throughout the 7-hour sleep period.
Although the major interest was concerned
with how the GSG and PSG differed during
sleep, it was also desirable to determine how
the two groups compared during specific
stages of sleep. Therefore, in addition to obtaining the mean value for each physiological
variable during total sleep, the mean values
for Stage 2, Delta, and REM sleep were also
computed. Table 3 shows the results obtained
during total sleep.
Rectal temperature. The PSG had consistently higher mean values on all parameters
of temperature investigated. The mean differences obtained significance during Stage 2
sleep ( £ < . 0 2 5 ) , Delta sleep (p < .02),
REM sleep (p < .OS), and total sleep (p <
.02). Considering that the range of individual
5 means during sleep equaled 1.64 degrees, a
mean difference of .34 degrees was quite substantial. The notable consistency of the differences between the groups is depicted in Figure
1; the lowest mean temperature readings for
the PSG were considerably higher than the
highest mean readings for the GSG. The GSG
showed a trend toward an increase in body
temperature during the last hour and a half of
sleep which is consistent with Kleitman's
(1963) findings, whereas the PSG showed a
slight decrease during the last 2 hours.
Phasic vasoconstrictions. The PSG had a
higher mean number of phasic vasoconstrictions per minute during all stages of sleep
and during most sleep and presleep periods.
The PSG means were significantly higher for
Stage 2 sleep (p < .005), NREM sleep (p <
.02), and for total sleep (p < .02). Figure 2
shows the distribution of the rate of vasoconstrictions; both groups, especially the PSG,
showed a trend toward cyclic variation in
vasoconstriction rate which appeared similar
to the cyclical alternation of REM and
NREM sleep phases.
Body movements. The PSG had more bodymovement activity than the GSG during all
stages of sleep; the mean differences were
significant for Delta sleep (p < .02) and total
sleep (p< .05). The PSG also had higher
body-movement means during Stage 2 and
REM sleep; however the mean differences
were not significant. No difference in the
rate of body movements per hour was found
between Stage 2 and REM sleep, but a very
substantial reduction in body activity during
Delta sleep was observed. Figure 3 shows the
mean number of body movements that occurred during each 30-minute interval of the
total sleep period. The two groups were more
consistently different during the latter half
of the night than during the first half. Bodymovement rate for the GSG was comparatively
LAWRENCE J. MONROE
260
1.00
I"
I .40
.20
I
10
20
3
30
PRE-SLEEPWINJ
I
I
1
4
SLEEP PERIOD IN HOURS
FIG. 2. Comparison of GSG and PSG on rate of vasoconstrictions.
stable during the last S hours, whereas the
PSG rate showed a gradually increasing trend
throughout the night.
Heart rate and pulse volume. The PSG had
higher mean values on all parameters of heart
rate investigated, and although the REMsleep difference approached significance (p <
.10), none of the differences reached significance. The PSG had slightly higher mean
values than the GSG on pulse volume level
during all phases of sleep; however, none of
the differences was significant. For both
groups, heart rate and pulse volume tended
to decrease with sleep onset and with each
subsequent hour of sleep throughout the night.
Basal skin resistance. The PSG means were
higher than the corresponding GSG means on
all investigated parameters of basal skin resistance. The differences between the means
were significant for Stage 2 sleep (p < .02),
i
i
i
3
4
SLEEP PERIOD IN HOURS
FIG. 3. Comparison of GSG and PSG on rate of body movements.
261
GOOD VERSUS POOR SLEEPERS
229
200
175
150
125
100
75
50
25
I
10
20
30
PRE-SUEPWIN.)
3
I
I
I
I
4
SLEEP PERIOD IN HOURS
FIG. 4. Comparison of GSG and PSG on basal skin resistance.
Delta sleep (p < .02), REM sleep (p < .01),
and total sleep (p < .02). The two groups
differed less during wakefulness than during
sleep, and differed more during REM sleep
than NREM sleep. For both groups, lowest
skin-resistance readings were obtained during
Delta sleep while highest readings were obtained from REM sleep; this difference
probably represents the effect of sleep per se
rather than stage differences. Inspection of
Figure 4 shows the gradual rise of skin resistance during the night, and because more Delta
sleep accumulates early in the night and more
REM sleep late in the night, lower resistances
were associated with Delta sleep and higher
resistances with REM sleep.
Not only did the GSG and PSG differ
physiologically during sleep, but, very importantly, they were substantially different
during the presleep period of wakefulness on
heart rate, rectal temperature, pulse volume,
and vasoconstriction rate. The earliest estimate of the level of autonomic functioning
during wakefulness was obtained by using the
first recorded measure of the presleep period.
A comparison of group means on temperature,
heart rate, and vasoconstriction rate, showed
that PSG 5s had significantly higher values
than GSG 5s. On certain measures the differences between groups were at least as large
during wakefulness as during sleep. For example, the PSG averaged 7.4 more pulse beats
per minute than the GSG at the start of the
presleep period, 6.2 more beats per minute
averaged over the 30-minute presleep period,
S.S more beats per minute during REM sleep,
and 3.9 more beats per minute during total
sleep.
Personality Measures
Numerous writers have discussed the association between personality functioning and
sleep disturbance (White, 1948). Disturbance
of sleep is one of the most frequent complaints
of the emotionally disturbed person. Clinical
evidence suggests that persons who are diagnostically categorized as "neurotic" or "psychotic" present many complaints about their
sleep; however, it has not been empirically
established that persons who are categorized
as poor sleepers are in fact emotionally disturbed or even more neurotic than individuals
who are not classified as poor sleepers. To
determine whether personality differences exist
between good and poor sleepers, the Minnesota Multiphasic Personality Inventory
(MMPI) and the Cornell Medical Index
(Brodman, Erdmann, & Wolff, 1956) were
administered to all 5s under uniform conditions. Table 4 compares the GSG and PSG
on the 12 original scales of the MMPI, plus
3 additional scales which are frequently used
in conjunction with the standard scales.
Analyses of the MMPI scales showed
marked differences between good and poor
sleepers in their psychological makeup. Table 4
LAWRENCE J. MONROE
262
TABLE 4
DIFFERENCES BETWEEN THE GSG AND PSG ON MMPI
PERSONALITY SCALES
GSG
MMPI
scale
K
F
Hs
D
Hy
Pd
MJ
Pa
Ft
Sc
Ma
Si
WA
WR
ES
Group
differences 0
PSG
M
SD
17.56
5.06
2.19
17.31
20.69
16.31
28.12
9.44
S.94
8.38
17.31
21.63
6.38
16.19
52.50
4.71
2.69
1.74
3.73
4.04
3.96
5.18
2.49
3.46
4.76
3.09
5.52
3.60
4.89
3.37
M
SD
13.50 4.39
9.00 5.12
5.75 5.59
23.56 6.43
23.13 5.52
19.56
5.28
32.56 4.56
11.13
2.55
15.19
9.83
18.19 12.33
19.25 6.09
30.69 11.18
14.94 10.37
15.38
4.15
46.63 6.68
-Mnm
(
4.06
3.94
3.56
6.25
2.44
3.25
4.44
1.69
9.25
9.81
1.94
9.06
8.56
0.81
5.88
2.33*
2.41*
2.41*
3.52*****
1.27
1.72
2.46*
2.19*
3.17****
2.58**
0.97
3.26****
2.73***
0.43
2.93***
B
All tests of significance were based on MMPI raw
scores.
*p <.05.
**t < .025.
***p <.02.
****4, < .01.
***** t <.005.
showed that the GSG 5s averaged significantly higher scales on K (p < .05) and £5
(p < .02); both these findings indicate
greater psychological health in terms of adaptiveness and the availability of ego resources.
The PSG averaged higher scores (in the
psychopathological direction) on 12 of the 13
clinical scales investigated; group differences
were significant for 9 of the 13 scales.
The Cornell Medical Index results also revealed greater psychosomatic and emotional
disturbance for poor sleepers. The PSG had a
mean of 14.88 somatic symptoms compared
to a mean of 5.19 for the GSG (t = 3.77,
p < .005). The PSG had a mean of 9.25
emotional symptoms compared to the GSG's
mean of 1.31 (t = 2.61, p < .02).
Dreaming and psychopathology. There is
considerable interest and potential significance
in the relationship between dreaming and
personality functioning, independent of good
and poor sleep (Rechtschaffen & Verdone,
1964). In order to directly ascertain the
relationship between the amount of REM
time (dreaming) and indexes of psychopathology, correlations were computed between
total REM time (percentage of sleep time)
and MMPI scales for the GSG and PSG
separately and in combination. For good
sleepers, the correlations between REM time
and psychopathology were generally negative
and of small magnitude. For poor sleepers,
correlations between REM time and psychopathology were all positive and generally
of much greater magnitude. Of the 10 clinical
scales investigated, 5 scales correlated significantly with REM time for poor sleepers
while none of the correlations was significant
for good sleepers, or for the combined sample
of good and poor sleepers. The scales which
were significantly associated with dreaming
for poor sleepers were: Hs, .70; Hy, .70; Pd,
.79; Pa, .64 (p < .01 for Hs, Hy, Pd, and
Pa); Sc, .52 ( p < . Q S ) ; Ma, .48; Pt, .48
(.10 > p > .05). For good sleepers, correlations between dreaming and the above scales
were: Hs, -.11; Hy, .03; Pd, -.02; Pa,
-.23; Pt, -.44; Sc, -.18; and Ma, .06.
Thus, the two groups were clearly different
with respect to the degree and direction of
association between dreaming and psychopathology.
DISCUSSION
The self-report criteria used to differentiate
good and poor sleepers successfully predicted
group differences in the experimental situation. Good and poor sleepers were originally
differentiated on the basis of their reports of
their home sleep behavior in terms of how
quickly they fell asleep, how difficult it was
for them to fall asleep, and how frequently
they awoke during the night. In the experimental situation, the GSG 5s fell asleep more
quickly than the PSG 5s, averaged considerably more sleep time (p<.05), less time
awake (p < .05), and had fewer awakenings
(p < .05). Therefore, there was a correspondence between group differences in self-reported sleep behaviors and electrophysiological sleep indicators. When the sleep
cycle was considered as a unit, the major
differences in sleep patterns of good and poor
sleepers were accountable in terms of differential proportions of Stage 2 and REM sleep.
When type of sleep was expressed in terms of
the percentage of total sleep, it was found
that the PSG averaged significantly more
GOOD VERSUS POOR SLEEPERS
Stage 2 sleep and significantly less REM
sleep than the GSG. Total REM percentage
for good sleepers (24,34) was very similar to
the figures of 23.74% and 24.25% reported
by Antrobus, Dement, and Fisher (1964) and
Rechtschaffen and Verdone (1964). Total
REM time for poor sleepers was significantly
lower than that of the GSG, and similarly
lower than that for normal 5s used in other
studies.
The poor sleepers slept "much better" than
could have been expected solely on the basis
of their responses to the 5-selection items.
The postsleep rating of the majority of poor
sleepers confirmed this impression; 75% of
the PSG 5s rated their experimental sleep as
average or better than average. By comparison,
63% of the GSG 5s rated their laboratory sleep
as poorer than average; none of the good sleepers rated their sleep as better than average on
the experimental night. When questioned about
their postsleep ratings, good sleepers reported
that they rated the night's sleep as average
or poorer than average simply because waking
up even once was considered an unusual
deviation from their normal sleep pattern.
Thus, a disturbance that was considered to be
minor or usual by poor sleepers was considered to be very unusual or even disturbing
by good sleepers.
Significant physiological differences between the groups were observed on rectal temperature, phasic vasoconstriction, skin resistance, and body-movement measures. It may
be that these samples of good and poor
sleepers were different in some basic autonomic respect which was not determined
in this study, and that the specific physiological differences found were but manifestations
of a more primitive, underlying difference^
One general interpretation of the differences
in psychophysiological functioning between
the GSG and PSG seems warranted: questionnaire-defined good and poor sleepers differ not
only in amount of EEG-defined sleep and
number of spontaneous awakenings from sleep
observed in the laboratory, but during sleep
the physiological functioning of poor sleepers
on such measures as rectal temperature, body
movement, heart rate, and phasic vasoconstriction is closer to the waking end of the
263
sleep-wakefulness continuum than for good
sleepers. Phrased simply, self-reported poor
sleepers not only sleep less, but the sleep they
obtain is more "awake-like" than that of good
sleepers. Differences in basal skin resistance
were inconsistent with this trend.
Significant differences between good and
poor sleepers were demonstrated on the MMPI
and Cornell Medical Index. One interpretation of this difference suggests a differential
response bias, with poor sleepers being more
prone to subscribe to symptomatic complaints on the MMPI and the Cornell Index,
as well as on the sleep questionnaire, than
good sleepers who tended to be more guarded.
The K and F validity scores are consistent
with this possibility. Similarly, an apparent
exaggeration of the time required to fall
asleep by poor sleepers also suggests response
bias. An alternative interpretation suggests
that poor sleepers were empirically and clinically neurotic compared with good sleepers
despite the possible contributing factors of a
response bias. In addition to the significant
scale score differences, it was the experimenter's distinct impression that the poor
sleepers were less well adjusted; for example,
the poor sleepers complained more about discomfort in the experimental situation, they
asked more questions about possible dangers
of recording techniques, and they showed a
higher incidence of peculiar behaviors. One
poor sleeper awoke screaming that his feet
"are on fire," another accused the experimenter of "putting thoughts in my head" via
the recording apparatus, and two other poor
sleepers complained of being awakened by
"electrical stimulation." Such behavior was
absent in the good sleepers. Second, a number
of significant correlations were observed between physiological functions and personality
scale scores. Whereas there is little apparent
basis to expect correlations between responsebias tendencies and physiological functions,
numerous relationships between physiological
functioning and personality disturbance have
been demonstrated.
Accepting the assumption that higher
scores on the personality scales indicate
greater likelihood of psychopathology, one can
conclude from the different patterns of cor-
264
LAWRENCE J. MONROE
relations that for the good sleepers there was a
slight negative relationship between amount
of dreaming and personality test scores. For
poor sleepers, there was a significant positive
relationship: poor sleepers with higher MMPI
scores had more REM time than poor sleepers
with lower MMPI scores; however, poor
sleepers as a group had much less REM time
than good sleepers. This is indeed a perplexing
relationship because it unparsimoniously suggests that psychopathological test scores are
associated with dreaming in different directions: first, that psychopathological test results in general are associated with reduced
REM time, and second, that increasing degrees of psychopathology are associated with
more dreaming, at least up to the same proportion of REM time for the good sleepers. As
this is an important relationship, replication
and subsequent investigation is needed before
a meaningful formulation can be offered.
It is clear that there are at least two major,
different kinds of sleep, namely REM and
NREM sleep, and because each appears to
serve different psychological and physiological
functions, attention must be given not only
to amount of sleep but to the distribution of
sleep stages as well. With regard to qualitative aspects of sleep, various soporifics have
been used with varying degrees of effectiveness in inducing or maintaining sleep; however, there is little information about the type
of sleep the various soporifics induce. Oswald,
Berger, Jaramillo, Keddie, Olley, and Plunkett
(1963) have reported that one soporific (heptabarbitone) decreased the proportion of REM
sleep and increased the amount of Stage 2
sleep and the amount of body-movement activity; sleep obtained under the effects of
heptabarbitone shares many of the characteristics of poor sleep observed in the present
study. If, as Dement (1960) suggests, REM
sleep serves important functions, soporifics
might indeed induce sleep but at the same
time have deleterious effects because of their
inhibition of certain stages of sleep. There is
a definite need for future research to emphasize qualitative aspects of sleep as well as
concern for the quantity, induction, and
maintenance of sleep.
REFERENCES
ANTROBUS, J., DEMENT, W., & FBHER, C. Patterns of
dreaming and dream recall: An EEC study. Journal of Abnormal and Social Psychology, 1964, 69,
341-344.
BRODMAN, K., ERDMANN, A., & WOLFF, H. Cornell
Medical Index health questionnaire manual. New
York: Cornell University Medical College, 1956.
DEMENT, W. The effect of dream deprivation.
Science, I960, 131, 1705-1707.
DEMENT, W. Dreams and dreaming. International
Journal of Neurology, 1965, 5, 168-186.
DEMENT, W., & KLEITMAN, N. The relation of eye
movements during sleep to dream activity: An objective method for the study of dreaming. Journal of Experimental Psychology, 19S7, 53, 339-346.
KAMIYA, J. Behavioral, subjective, and physiological
aspects of drowsiness and sleep. In D. W. Fiske &
S. R. Maddi (Eds.), Functions of varied experience. Homewood, III.: Dorsey Press, 1961. Pp. 145174.
KLEITMAN, N. Sleep and wakefulness. Chicago: University of Chicago Press, 1963.
OSWALD, I., BERGER, R., JARAMILLO, R., KEDDIE, K.,
OLLEY, P., & PLUNKETT, G. Melancholia and barbiturates: A controlled EEG, body and eye movement study of sleep. British Journal of Psychiatry,
1963, 109, 66-78.
RECHTSCHAFFEN, A., & MARON, L. The effect of
amphetamine on the sleep cycle. Electroencephalography and Clinical Neurophysiology, 1964, 16, 438445.
RECHTSCHAFFEN, A., & VERDONE, P. Amount of
dreaming: Effect of incentive, adaptation to laboratory, and individual differences. Perceptual &
Motor Skills, 1964, 19, 947-958.
SNYDER, F. The new biology of dreaming. Archives
of General Psychiatry, 1963, 8, 381-391.
WHITE, R. W. The abnormal personality. New York:
Ronald, 1948.
(Received February 4, 1966)