Studying Dream Content Using the Search Engine and Dream Archive on Dreambank.Net
G. William Domhoff & Adam Schneider
University of California, Santa Cruz
NOTE: If you use this paper in research, please use the following citation, as this on-line version is simply a reprint of the original article:
Domhoff, G. W., & Schneider, A. (2004). Studying Dream Content Using the Search Engine and Dream Archive on Dreambank.net. Paper presented to the meetings of the American Psychological Society, Chicago, May 29, 2004.
This paper shows how the powerful search engine and large dream archive on dreambank.net, a scientific website containing over 17,000 dream reports, can be used to generate new findings on dream content that have potential theoretical implications. To demonstrate the usefulness of the site, searches based on several different word strings and phrases are used to study a wide range of dream reports. In addition, brief examples from two individual dream journals, one consisting of 2,022 dream reports over a three-year period from a college student, the other of 4.254 dreams reports over a 25-year period from an older woman, are used to show how the typical dream content of one person can be quickly studied for primary characters and themes. These individual cases also demonstrate a feature of the search engine that makes it possible to determine the consistency of a word or phrase over time, as well as a contingency analysis program that makes it possible to find relationships between various pairs of words or phrases. The findings using DreamBank.net are similar to those in studies using traditional forms of content analysis carried out by human coders. The fact that dream content in good part reflects everyday interests and preoccupations, is strikingly consistent over long periods of time, and is generally continuous with waking conceptions and concerns provides a framework for future theorizing about dreaming and dream meaning.
Numerous studies of dream reports from all over the world using several different systems of content analysis, but in particular the system resting on nominal categories developed by Calvin S. Hall and Robert Van de Castle (1966), have provided a replicable body of descriptive empirical findings concerning what people dream about. These findings reveal age, gender, cross-cultural, and individual similarities and differences of the kind that might be expected on the basis of studies of waking psychological variables. There are also studies of lengthy individual dream journals showing that most people are consistent over years or decades in what they dream about, and that the most frequent characters, social interactions, and activities in their dreams are continuous with their waking thoughts and concerns (Domhoff, 1996; Domhoff, 2003).
Although these studies are descriptive rather than hypothesis-testing in nature, they nonetheless have theoretical implications. First, they cast doubt on most of the assertions in traditional clinical theories, which claim there are large differences between dreaming and waking thought, and stress the opaque and symbolic nature of much dream content. Second, the general findings also are inconsistent with many tenets of the neurophysiologically based activation-synthesis theory of dreams, which emphasizes the allegedly discontinuous and bizarre nature of most dream content (Hobson & McCarley, 1977; Hobson, Pace-Schott, & Stickgold, 2000). By way of contrast, many of the findings from content analysis studies are consistent with a cognitive theory of dreams, which begins with the parallels between dreaming and waking thought, and therefore makes use of concepts developed on the basis of experimental studies of waking cognition (Antrobus, 1978; Domhoff, 2003; Foulkes, 1985; Foulkes, 1999).
Still, there remains much dream content that is not understood, and progress continues to be slow in overcoming this lack of understanding for a variety of reasons, including the inability to induce or manipulate dreaming to any significant extent, and the impossibility of receiving verbal reports on the process while it is occurring. Researchers who study dream content are by and large restricted to studying written or transcribed reports based on memories of the dream experience, which means that the data are two steps removed from dreaming itself. After all that, there are still further problems, such as the lack of good databases and the labor-intensive nature of any thorough and reliable system of content analysis.
Fortunately, problems with databases and reliable coding in a timely fashion can be overcome to some extent by the near-universal availability of high-speed personal computers and the increasing sophistication of their analytical software. It is the purpose of this paper to show how these technological advances can be used to build and analyze large databases by presenting results obtained from searches on DreamBank.net, a web-based research site available to everyone. Dreambank.net features an ongoing collection of dream reports, along with software programs that make it possible to perform many different kinds of content analyses in a 100% reliable fashion in a matter of seconds.
Data And Methods
DreamBank.net, or "the DreamBank," currently consists of over 17,000 dream reports and counting, 16,000 of which are in English, along with another 1,000 in German. (Other European languages could also be accommodated by the DreamBank.) Some of the reports are part of collections from a group of people, such as teenagers or college students, and others are part of a series of reports from an individual. All of the English-language dreams were collected in the United States. The German-language dreams come from college students in Germany (Schredl, Petra, Bishop, Golitz, & Buschtons, 2003) and Swiss children ages 9-15 (Strauch, 2003; Strauch & Lederbogen, 1999). The dream reports were collected in a variety of settings, ranging from the sleep laboratory to the classroom to personal dream journals kept for diverse reasons by several different individuals.
For example, there are dreams collected in classroom settings from young men and women at universities in Cleveland in the late 1940s. These dream reports were later used by Hall and Van de Castle (1966) to create normative findings for all the categories in their exhaustive coding system. There also are dreams collected by Hall and Van de Castle inside and outside the sleep laboratory from the same participants at the University of Miami in the 1960s (Domhoff & Schneider, 1999; Hall, 1966). The several personal dream journals on the site, ranging in length from 15 to 4, 254 dreams, are best thought of as the kind of archival documents that serve as "unobtrusive" measures of a given phenomenon (Allport, 1942; Baldwin, 1942). According to methodologists, such archival sources can be very valuable in psychology when they lead to similar results even though they were kept for diverse reasons (Webb, Campbell, Schwartz, Sechrest, & Grove, 1981). In addition, the baselines provided by the sets of dreams provided by children and young adults make it possible to determine how findings with an individual dream series differ from normative expectations, making analysis of such journals even more valuable.
The dream reports are analyzed using keyword strings and phrases that are entered into the search engine on DreamBank.net, which was written in the perl programming language. By default, the results of the searches are then converted into frequency counts and percentages that are presented in tables. An option on the search form makes it possible to determine the consistency of elements per a given number of dream reports in an individual series; another option makes it possible to find contingencies between two elements in a set or series of dream reports. All of the dream reports containing the search terms can be displayed in either a full or abbreviated form, with the abbreviated form containing the sentence with the relevant word or phrase. Either way, the word or phrase appears underlined and in boldface to make it easier to identify it for further analysis.
Although searches on the DreamBank are infinitely faster than anything that could be done in the past, and completely reliable in picking out words and phrases, for some analyses the findings have to be culled by means of human judgment to eliminate "false positives," that is, words or phrases that have a slightly different meaning in the context of the dream report or are used figuratively.
For the demonstration purposes of this paper, several brief analyses will be conducted. First, the frequency and type of religious and spiritual elements will be determined for the English-language dreams in the database. Second, a similar analysis will be carried out for references to sexual intercourse in dream reports. Third, a search for the word "flying" will be conducted to show how unusual dreams can be studied by means of the DreamBank. Fourth, analyses an analysis of a dream series from a college student will be carried out to show how word and phrase searches can reveal the main contents in a lengthy dream journal that otherwise could only be studied through dozens of hours of work on representative subsamples from the series. Fifth, the consistency of these phrases throughout the 25 years covered by a dream series from an adult woman will be determined. Finally, simple examples of how to determine whether or not there are contingencies between pairs of words and phrases in a dream series will be provided.
Religious and Spiritual Elements in Dreams
Using the breakdown of dream content into settings, characters, objects, and activities in the Hall and Van de Castle (1966) coding system as a template, Krippner, Jaeger, and Faith (2001) used a scale for uncovering religious and spiritual elements in dreams to determine the degree to which such elements are present in dreams. This scale can be approximated using DreamBank.net because there are a limited number of terms that relate to religious and spiritual concerns, and these terms usually do not have additional, non-religious meanings, except when used figuratively (e.g., it was a "church-like" situation. For example, the settings are limited to places like churches, temples, and mosques; the characters to a handful of gods, angels, and leaders; the activities to such matters as praying and worshipping; and the objects to sacred objects such as crosses, chalices, and altars.
The religious word searches were carried out on the entire English database of dream reports. Such a search yields three main results. First, it shows that religious and spiritual elements are generally infrequent in dreams. Only 3.3% of the dream reports mentioned places like churches, cathedrals, temples, and chapels; only 1.6% mentioned religious characters such as deities, ministers, and priests; only .8% mentioned specific religions or religious denominations; only .9% mentioned religious concepts such as worship, sacred, and nirvana; and only .9% mentioned religious objects such as sacred books, altars, and crucifixes. Second, it provides a few hundred dream reports that can be studied to see how religion is portrayed in dreams. For example, the most prominent religious object in dream reports is the altar, but it appears primarily in dreams about weddings, where the couple is standing before the altar. Should such dreams be counted as containing "religious and spiritual" references? Third, these findings provides a useful baseline for looking at individual dream series to see if there are individual differences.
When we turn to the individual dream series in the DreamBank, we find, as might be expected from the results just reported, that most of them have few or no mentions of religious or spiritual elements. However, there are two striking exceptions. "Merri," an artist brought up in a strict Protestant tradition, dreams frequently of religious settings, objects, and activities from her childhood, often in conjunction with her parents -- even though she is no longer a believer. She also dreams of what are often termed "spiritual" issues, and she indeed now thinks of herself as a spiritual person. As for "Emma," who became highly involved in religion as a young married woman, dreams of the church were frequent for the next 37 years. She also dreams of the ministers who served at her church over the years -- especially one for whom she had a strong emotional affection. She also dreams of taking part in religious ceremonies.
This brief study of one type of dream content establishes two key points related to general studies of dream content using DreamBank.net. First, it is possible to determine normative baselines. Second, it is then possible to make studies of sets and series that are above these baselines, with an eye to making discoveries that might have theoretical implications. In this instance, the two individual series that are well above the baseline suggest that dream content does reflect a person's waking interest and concerns, supporting past studies using different coding systems (Domhoff, 1996; Domhoff, 2003).
Sexual Intercourse References in Dreams
Although dreams and sexuality are often closely related in popular culture, perhaps in part due to Freud's well-known theory concerning the hidden sexual meanings said to be present in most dreams, systematic studies of dream content suggest that there is very little explicit sexual content in dreams. In the Hall and Van de Castle (1966, p. 181) normative sample, only 12% of male dreams and 4% of women's dreams had as much as a sensual thought or a romantic kiss; the percentage of dreams that include sexual intercourse is only 3.4% for the men and 1.0% for the women.
Since our past research suggests that a relative handful of terms are usually used by adults in reporting their sexual activities in dreams, it is possible to attempt generic searches for references to sexual activities in dreams. Such searches will miss some references to sexual activities, and will pick up some false positives, such as "we decided not to have sexual intercourse," but the baselines and samples that are obtained are nonetheless useful for studying sexuality in dreams. The most useful terms of this purpose include the past or present tenses of "making love," "having sex," and "kissing." Exact terms and euphemisms referring to sexual organs also can lead to references to sexual interactions. In studies of long dream series from individuals, it is possible, and even necessary, to tailor the sexual references word string to include pet terms and idiosyncratic phrases, thereby making the searches even more encompassing.
For purposes of this paper, the focus will be on the frequency of sexual intercourse because terms like "kissing" and terms for sexual parts lead to many false positives. When the various tenses of "making love" and "having sex" are searched for in the same dream reports that Hall and Van de Castle used to create their normative findings, the results show an even lower frequency of sexuality references found with their more elaborate and precise coding categories for sexuality: 2.0% for men and 0.4% for women. However, as with religious and spiritual elements, the search provides a sample of dreams that can be looked at for general characteristics, from which we learn that sometimes the love making does not take place after all, or is interrupted by others, or is rendered problematic in the dreamer's mind because the partner is an unexpected one.
The Frequency and Content of "Flying" Dreams
Popular culture stresses the bizarre and unusual nature of dream content, and dream researchers argue about the degree to which this image is accurate. Researchers have tried to classify these kinds of elements into a handful of categories and determine their frequency. One type of bizarreness involves highly unusual or impossible events, such as flying under one's own power, having teeth suddenly loosen or fall out, appearing without clothes in public, or falling through space. Questionnaires asking people if they have ever experienced such dream elements lead to findings in which a majority say they have (Nielsen et al., 2003).
DreamBank.net provides a way to approach some aspects of bizarreness in a large-scale and systematic fashion. For example, elements such as flying and losing teeth can be studied for their frequency and context because a few specific words capture most references to such events. Studies of metamorphoses are also tractable because they are usually described by the phrases "turns into," 'changes into," "is transformed," and "becomes." Abrupt changes in characters, activities, and settings are often indexed by "suddenly" or "all of a sudden."
For purposes of this paper, group and individual dream reports were searched for the few terms that reference the experience of flying. The results were analyzed for frequency and context. Turning first to 3,309 dream reports in sets of dreams from children, teenagers, and young adults, we found that flying, gliding, or floating appeared in 134 dreams, which is 4% of the total. When we scrolled through the 134 dreams to see how many involved the dreamer or some other character flying under his or her own power, we found that 106 of the 134, or 79%, were false positives. They either described realistic events, such as flying in an airplane, floating in water, or gliding on a surface, or else were used metaphorically (papers were "flying" around the room, the person was "floating" after hearing the good news). Thus, only 18 of the dream reports had characters who were flying under their own power, which is 0.5% of the total reports. This is also the percentage we found when we restricted our search to the dream reports that Hall and Van de Castle used to establish the norms for their coding system. In addition, this is the percentage found in a study of 983 dream reports collected at the University of California, Santa Cruz over a two-week period from 126 students (Domhoff, 1996, p. 198). It thus seems very likely to us that flying occurs in less than 1% of dreams. Many people claim to have had such a dream, but it is unlikely that they have had one very often.
When we turn our attention to individual series, we find that most people do not differ from the baseline expectations. However, Elizabeth, an adult woman who keeps a dream journal as part of her involvement in dream discussion groups, had 10 such dreams out of 564, which is 1.8% of the total. In these dreams she flies when she is confronted by a physical obstacle she wants to by-pass, such as a wall or boulder, or is facing a danger from which she wants to escape.
The rarity of flying dreams, and other "typical" dreams that are so often mentioned in everyday conversation, when combined with the rarity of religious and sexual elements, raises the question of what people usually dream about, a topic that is discussed in the next section on the basis of searches in DreamBank.net.
The Substance of Dream Content
As noted in the Introduction, most studies of dream content suggest that the majority of dreams deal with everyday settings, characters, and activities. This past finding can be tested using individual dream series on the DreamBank. For this purpose, a dream series from a college student with the code name "Kenneth" provides a good example. Kenneth wrote down every dream he remembered for this first three years of college, a total of 2,022 dreams, which is an average of two dreams per night. Reading through the first 50 to 75 of his dreams, it is clear that he dreams frequently of his family and friends. He is also driving a car or truck, eating, playing sports, or taking part in outdoor activities, such as boating, fishing, and hunting. DreamBank.net makes it possible to see how frequent these characters and activities are in the entire series. In fact, either his mother or his father appear in 23.9% of the dream reports, and friends in 53.9%. If we ask what percentage of the dream reports have at least one parent or friend, the answer is 62.6%. Terms relating to eating appear in 13.7%, terms relating to driving in 24.5%, terms related to sports in 6.1%, and terms relating to outdoor activities in 17.0%. Overall, 76.7% of the dream reports mention at least one of the 18 words we entered that have to do with his parents, friends, eating, driving, playing sports, or taking part in outdoor activities.
Results such as these, which can be duplicated with other series in the DreamBank, do not refute the claim that dreams sometimes contain highly unusual content. Some people have experienced the sensation of flying under their own power in dreams, or awakened with the distasteful memory of a dream in which their teeth became loose and fell out. Still others have dreams of unusual creatures or unlikely adventures. The murder rate is very high in dreams, and sex sometimes happens with people who would be unlikely, and often unwanted, partners in waking life. However, the findings of most dream studies, now supported by our brief example from the DreamBank, is that most dreams deal with everyday concerns and interests. We therefore think this should be one key starting point in theorizing about dreams. Once that starting point is established, then the unusual settings, characters, and events can be added to the theory.
Consistency over Time in a Dream Series
The major unexpected finding from studying several different lengthy dream series using the Hall and Van de Castle (1966) coding system is how consistent dream content is over years and decades for most people, whatever their motives may be for writing down their dreams (Domhoff, 1996, 2003). This result is best established for adults who wrote their dreams down between the ages of 25 and 75, but there is one unpublished study of a young male showing consistency between the ages of 17 and 25 (Schneider & Domhoff, 1995). DreamBank.net makes it possible to repeat such studies in a matter of a few seconds using familiar terms such as "mother," "father," and "house," as well as words and phrases specific to an individual dream series.
For purposes of this paper, we chose to look at the consistency in the Barbara Sanders series because it contains a very large number of dreams and covers 25 years. This series is also of interest because a Hall and van de Castle coding of a representative sample of 250 of her dream reports for several different categories found that the first 125 did not differ from the second 125 (Domhoff, 2003). We compared her first 3,115 dreams, which she wrote down before we met her, with the 1,138 she has given us since that time. At least one of the 13 main people in her life (parents, ex-husband, three siblings, three children, granddaughter, and three best women friends) appear in 33.6% of the dreams in the first set and 35.1 percent of the second set. Her continuing interest in theatrical productions, as a writer, actor, and producer, is reflected in the fact that 4.9% of the dreams in the first set contained one of several terms related to this activity, as compared to 5.2% for the second set.
We also compared the first and second sets using long word strings for each of the five emotions that are coded for in the Hall and Van de Castle coding system: anger, apprehension, sadness, confusion, and happiness. The percentages are very similar, with the biggest difference, 4.6 percentage points, on happiness. For the total number of dreams with at least one emotion, the figures are virtually identical, as seen below:
| || Anger || Apprehension || Sadness || Confusion || Happiness || Any Emotion At Least Once |
|Set 1 ||17.5||27.6||10.1||10.8||15.6||54.6|
|Set 2 ||14.2||28.1||8.6||13.6||20.2||56.6|
The findings on the percentage of dreams with at least one emotion is of interest for another reason: in the Hall and Van de Castle normative study of women's dreams with their coding system, 57.2% had at least one emotion, almost exactly the same as what we found using word strings on the DreamBank.
These results do not deny that there is day to day fluctuation in dream content, or that striking external events or some unusual physical condition, such as an upset stomach, may sometimes affect dream content. However, they do suggest that most dream content must be drawn from a reasonably circumscribed set of schemata and scripts. Such a result is completely unanticipated and unexpected by most tradition dream theories.
Contingencies in Dream Content
Contingency analysis is a method for determining what elements tend to be related to each other in a content study where the measurements are at the nominal level. More specifically, it is a nonparametric statistic that provides the exact probability for the relationship between two or more elements in a text (Osgood, 1959). In the case of DreamBank.net, there is a program for determining contingencies between two elements, which makes use of the formula for the significance of differences between two proportions to calculate p values.
For example, since "my dad" appears 147 times in the Kenneth series, and "my mom" appears 274 times, it is likely that they would appear together by chance 19 times (the expected value). However, they appear together 36 times, a difference between the observed and expected values that has a p value of .03. There is also a contingency between Kenneth's terms for sexual relations and his girlfriend, with a p value of .00001; even so, there are also many sexual interactions with characters other than his girlfriend, which might lead to other issues worth exploring. The two examples used here are not unexpected, but they make a basic point: building on such contingencies might make it possible to see what elements are linked together in a dreamer's conceptual system. That is one direction we hope to explore in our future research using the DreamBank.
Discussion And Conclusion
The findings using DreamBank.net are similar to what has been reported with other systems of content analysis concerning the frequency and consistency of various dream elements, along with the continuity of most of these elements with waking concerns. These results therefore support the idea that DreamBank.net can be useful in furthering the understanding of dream content. Beyond this methodological conclusion, the findings also support the idea that dreams are usually a reasonably coherent simulation of the person's waking world, as emphasized in the work of laboratory dream researcher David Foulkes (1985; 1999). This is a conclusion that lends support to adopting a cognitive approach to dreaming and dream content. Such an approach stresses the parallels between dreaming and waking cognition, and therefore draws on the insights of cognitive science.
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