Dreams reflecting waking sport activities: A comparison of sport and psychology students

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Daniel Erlacher - Institute for Sport and Sport Science, University of Heidelberg, Germany
Michael Schredl - Sleep laboratory, Central Institute of Mental Health, Mannheim, Germany 

Bitte zitieren nach:
Erlacher, D. & Schredl, M. (2004). Dreams reflecting waking sport activities: 
A comparison of sport and psychology students. International Journal of Sport 
Psychology, 35(4), 301-308.

Inhaltsverzeichnis

Abstract

In the field of sports there is anecdotal evidence for the incorporation of athletic activity in subsequent dreams. The present study investigated dreams of sport students and psychology students with regard to sport related dream content. The findings support the continuity between frequent involvement of sport activities during the day and active participation in sport or sport themes in dreams. These findings will be discussed in the context of motor learning and REM sleep. In future research, the correlation between different performance levels for different sport activities during wakefulness and dream content should be studied in a more detailed way to generate a clearer understanding of the process of sleep-related learning.

Keywords: dream content, sport students, psychology students, sport activity


Introduction

In the field of sports there is anecdotal evidence for the incorporation of athletic activity in subsequent dreams, e.g. students from our university courses who practice skiing for their first time often reported dreams about skiing. In dream research this phenomenon is called the continuity hypothesis which states that the dream content reflects waking activities (overviews: Domhoff, 1996; Strauch & Meier, 1996). Even though the continuity hypothesis is largely supported by studies investigating different types of waking life experiences, e.g. divorce, stress (overview: Schredl, 2003), only a few studies that will be reviewed below studied the effect of athletic activity on subsequent dream content.

Hauri (1970) investigated the dream content after 6 hours of three kinds of evening activities: physical exercise, studying, and relaxation. Results showed that after the evening of exercise the participants rated their dreams with less physical activity than during the nights after studying or relaxation – a result which disconfirm the continuity hypothesis. However, a re-analysis of the dream reports of this study by independent raters (see Van de Castle, 1994) showed that the dream reports after the evening of exercise included more solitary physical and movement activities than the dream reports following the study condition. A replication study carried out by Browman and Cartwright (1982) did not confirm heightened physical activity in dreams after physical exercise in the evening. Whereas the two experimental studies found controversial results about the continuity of physical activities in the dream content, two dream series analyzed by Domhoff (1996) showed that persons who have a great interest in performing sports during waking life also reports above-average number of dreams about athletic activities. Additional support was provided Heishman and Bunker (1989) who found that 93 % of elite lacrosse players dreamed about lacrosse play and that 46 % frequently dreamed about their sport. Carprinter and Cratty (1983) showed that 19 of 21 waterpolo players reported dreaming about their sport. About 28 % of their total recalled dreams included waterpolo and these dreams increased as the season progressed and during important competitions. In an exploratory study (Mahoney & Avener, 1977) results indicated that the six gymnasts who were chosen for the Olympic team dreamed more often about gymnastic and sport success than the six gymnasts which failed the Olympic qualification. In addition, the amount of training correlated with the frequency of gymnast dreams and doubts about one’s gymnastic abilities (questionnaire score) correlated with having more tragic dreams. Similar results were obtained by Meyers, Cooke, Culle, and Liles (1979) studying elite racquetball players. Even playing a sport computer game often induce sport-related sleep-onset dreams (Stickgold, 2003).

The questionnaire studies clearly demonstrate a correspondence between frequent involvement of sport activities during the day and dream content for professional athletes, whereas the experimental studies with non-athletes showed inhomogeneous results about physical activities in the evening and dream content. Based on these data it was hypothesized that sport students with high frequent involvement of sport activities during the day will show more active participation in sport and sport themes in their dreams than psychology students with less frequent sport activities during the day.

Methods

Participants

The sample included 42 sport students (22 men, 25 women) whose mean age was 22.9 years (SD = 3.1) and 442 psychology students (67 men, 375 women) whose mean age was 23.5 years (SD = 5.7). Because of their curricular requirements the sport students are frequently involved in different sport activities and sport theory (physical courses, lectures, seminars etc.) during the day in contrast to the psychology students. For the content analysis a subsample of 36 sport students (16 male and 20 female; 22.9 years  3.3), who reported at least one dream report were compared to an equal number of psychology students who were randomly selected and matched by age and sex (16 male and 20 female; 22.9 years  3.2). Informed consent was obtained from the participants.

Dream Questionnaire and Dream Diary

In addition to demographic data, dream recall frequency was elicited by a seven-point scale (0 = never, 1 = less than once a month, 2 = about once a month, 3 = two or three times a month, 4 = about once a week, 5 = several times a week, 6 = almost every morning). The retest reliability of this scale for an averaged interval of 55 days is high (r = .85; Schredl, 2004). Additionally, emotional tone in dreams were measured by a five-point scale (-2 = overall negative to +2 = overall positive) and the intensity of dream emotions (1 = not intensive to 5 = very intensive). Each participant kept a structured dream diary over a two-week period (Schredl, 2002). In addition to a checklist measuring dream recall, participants were instructed to record their dream(s) as completely as possible and to rate the emotional tone of their dream(s). Up to five dreams were to be recorded.

Dream Content Analysis

Two rating scales were developed in order to measure sport activities within the dream: (1) every active participation of the dream-ego in sport (e.g. did the dream-ego actively participate in sport) and (2) every dream context including sports (e.g. did the dream-ego talk about sports or think about sports) was coded if at least once present in the dream. The interrater reliability for the first scale was high (93 %, N = 100 dream reports, unpublished data). For the second scale which has a similar format equally high interrater reliability would be expected.

Procedure

The sport students were recruited from the department of sport and sport sciences of the University of Heidelberg. Participation was voluntary and unpaid. The psychology students were recruited at the universities of Mannheim, Heidelberg, and Landau (see Schredl, Wittmann, Ciric, & Götz, 2003). First, participants completed the dream questionnaire. Second, the dream diary was kept over a two-week period without any further contact with the experimenter. Third, dream reports were collected, typed, randomly arranged, and scored on the dream rating scales by a judge blind to the identity of the dreamers.

Statistical analyses were carried out using the SAS for Windows 8.02 software package. In order to control for sex and age, analysis of covariance (ANCOVA) have been computed. Similar, ANCOVAS were used for controlling number of dreams and length.

Results

In Table 1, the means and standard deviations for dream recall frequency (questionnaire and dream diary), emotional tone of dreams, and intensity of emotions in dreams are depicted. No statistical significant differences between sport students and psychology students were found for all four dream variables with gender and age statistically controlled.


Table 1. Means and standard deviations for dream variables.

Sport students (N = 47) Psychology students (N = 442) Statistical Test 1
Questionnaire Frequency of dream recall 3.60 ± 1.50 4.44 ± 1.19 F = 0.1; p = .7523 2
Emotional tone of dreams 0.28 ± 0.77 -0.05 ± 0.92 F = 0.9; p = .3370
Intensity of emotions in dreams 3.53 ± 0.83 3.97 ± 0.82 F = 0.3; p = .5922
Dream diary Frequency of dream recall 2.93 ± 2.89 (N = 42) 4.76 ± 3.14 (N = 440) F = 3.0; p = .0822

note. 1 ANCOVA (factors: group (depicted), gender, interaction; covariate: age); 2 Ranks have been analyzed


The 36 sport students reported 99 dreams and the matched psychology students 135 dreams. In 26 % of the dream reports (n = 26), the sport students participated as the dream-ego in sport activities compared to 9 % of the dreams (n = 12) reported by the psychology students. Further, 38 % of the dream reports (n = 38) from the sport students thematically contained sport activities compared to 14 % of the dreams (n = 19) reported by the psychology students. The psychology students reported significantly more and longer dreams (see Table 2). With respect to the self-rated dream emotions no differences were found between the groups. On average, the sport students reported significant more dreams with sport activities – both in active participation and sport themes – than the psychology students (controlled for number of dreams per subject and dream length).


Table 2. Means and standard deviations for dream content variables.

Sport students (N = 36) Psychology students (N = 36) Statistical test
Positive emotions 1.24 ± 0.96 0.96 ± 0.81 t = -1.3; p = .1921 1
Negative emotions 1.52 ± 1.04 1.60 ± 0.83 t = 0.4; p = .7229 1
Number of dreams 2.75 ± 1.63 3.75 ± 1.30 t = 2.9; p = .0052 1
Amount of words 77.85 ± 94.45 151.25 ± 97.25 t = 3.3; p = .0018 1
Number of dreams with active participation in sport 0.72 ± 0.85 0.33 ± 0.53 F = 16.7; p = .0001 2
Number of dreams with sport themes 1.06 ± 1.04 0.53 ± 0.65 F = 24.0; p = <.0001 2

note. 1 t-test; 2 ANCOVA (factor: group (depicted); covariates: number of dreams, amount of words)


Discussion

The findings of the present study support the continuity between frequent involvement of sport activities during the day and active participation in sport or sport themes in dreams.

Before interpreting the results regarding the relationship between waking and dreaming, it should be mentioned that other variables like dream recall frequency and emotion in dreams did not differ between the sport students and the psychology students. The higher diary dream recall frequency in the psychology students is largely explained by gender (more males in the sport sample). Large-scaled surveys have shown that women tend to recall more dreams than men (Schredl & Piel, 2003). For the content analysis, differences in possible confounding variables (number of reported dreams and dream length) have been statistically controlled. One might speculate that these differences in number of reported dreams and dream length are a consequence of the presumable higher interest in dreams in the psychology students.

It can be assumed that the sport students are more frequently involved with sport activities during the day than the psychology students, nevertheless, it would be beneficial to measure the exact amount of time which the students participated in sports during the days for the period of the study. This measure would be interesting to investigate the correlation between the time spent with sport activities during the day and the occurrence of sport activities in dream content. Schredl and Hofmann (2003) reported significant correlations for various day time activities and dream content, for example the amount of time driving a car during the day correlated with the occurrence of driving a car in the dream (r = .321). The authors showed further that cognitive activities (e. g. reading, writing) occur less frequently in dreams in comparison to other activities which involved complex motor skills (e g. talking, walking, driving a car etc.).

Sport is a frequent theme in the dreams of sport students, similar results were shown for people with high interests in athletic activity in long time dream series (Domhoff, 1996) and professional athletes (c.f. Carprinter & Cratty, 1983; Mahoney & Avener, 1977). The frequent occurrence of complex motor skills might reflect motor learning which has been shown to take place during sleep (Walker, in press). In several experiments it was demonstrated that the amount of REM sleep is correlated with an increase in procedural learning (overview: Maquet, Smith, & Stickgold,, 2003), for example, Fischer, Hallschmid, Elsner, and Born (2002) showed that after learning a finger sequence the performance was more pronounced after a period of sleep than after the same period of time of wakefulness and that the improvement was proportional to the time spent in REM sleep (r = 0.61). So far there are only a few studies which studied the correlation between motor learning and dream content. DeKoninck, Prevost, and Lortie-Lussier (1996) reported that persons who incorporated visually altered dream elements in their dreams after extensive pre-sleep training of motor tasks which wearing a visual inverting prism performed better in the morning in these tasks. Revonsuo (2000) proposed in the framework of the threat simulation theory that the simulation of perceptual and motor skills in dreams leads to enhanced performance in corresponding real situations.

Some studies (c.f. Karni, Tanne, Rubenstein, Askenasy, & Sagi, 1994), showed that the amount of REM sleep learning a high influence on the learning process of novel tasks, it can be hypothesized that learning of new tasks leads to more task related dream content than previously learned tasks. Therefore, in further studies not only the amount of time spent with sport activities during the day should be correlated with the dream content but also the performance level the person has with this motor skill (“novices” vs. “experts”) should be measured. In addition, it should be studied whether different pattern in dream content may be found in different types of sports.

To investigate the learning effects of performing motor skills in dreams on performance in wakefulness in a more sophisticated way, the lucid dreaming paradigm would be particularly suitable because lucid dreamers are able to execute prearranged tasks (e.g. new motor task) in their lucid dreams (Erlacher, Schredl, & LaBerge, 2003). Anecdotal evidence has been reported by Tholey (1983) that training of complex movements in lucid dreams enhanced performance in wakefulness and, thus, lucid dreaming would be a method – similar to mental practice – for professional athletes to improve their performance.

To summarize, continuity between sport activities during waking life and dreaming has been demonstrated in this study. Those findings were discussed in the context of motor learning and REM sleep. In future research, the correlation between different performance levels for different sport activities during wakefulness and dream content should be studied in a more detailed way to generate a clearer understanding of the process of sleep-related learning.

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