The SDDb baselines for most recent dreams (MRDs) and memorable dreams (MemDs) give a very precise and empirically based answer to this question.
MRDs tend to use more words relating to perception, emotion, cognition, social interactions, and culture.
MemD tend to use more words relating to flying, air, family, animals, fantastic beings, Christianity, and death.
Overall, MRDs are more anchored in present waking circumstances, while MemDs seem to have less connection to current social reality. MRDs reflect more of daily life, while MemDs express deeper existential themes.
These results derive from 828 female MRDs and 691 male MRDs, compared to 801 female MemDs and 504 male MemDs. You can see the spreadsheet here.
With the help of Dominic Luscinci at Far West Research, I analyzed these four sets of dreams in terms of their similarities and differences, adjusting the levels of statistical significance to account for multiple tests in each word class to protect against type 1 errors. Fisher’s Exact Test was used in cases where the criteria for chi-square testing were not present.
Before getting into the MRD vs. MemD comparison, I wanted to know what gender differences were most significant. I found that female MRDs and MemDs are more likely than male reports of both types to include references to emotions (especially fear), characters (especially family), speech, and friendly social interactions. Female MRDs have more perception and cognition, while male MRDs have more physical aggression and sexuality.
There are fewer gender differences in the MemDs than the MRDs.
Then I looked at the MRDs and the MemDs to see what differences show up for both males and females. I found that MRDs for both genders have more references to emotion, cognition, social interactions, and culture. MemDs have more references to nature (especially air and flying), characters (family, animals, fantastic beings), Christianity, and death. The female MemDs have more fire, falling, and physical aggression words. The male MemDs have more chromatic and achromatic colors.
There are many more differences between MRDs and MemDs than between the males and females. The comparison with the fewest differences was female MemDs vs. male MemDs; these two sets of dreams were the most like each other.
My first reaction to these findings was surprise that the MRDs had more words relating to perception and emotion, since I expected these indices of intensity and vividness would be more frequent in highly memorable dreams.
But I also felt good because these results basically replicate a 2011 study I did with Ernest Hartmann on big dreams. In the conclusion of that article we wrote “people’s big dreams are distinguished by a tendency toward ‘primal’ qualities of form and content: more intense imagery, more imagery picturing nightmarish emotions, more nature references, more physical aggression, more family characters, more fantastic/imaginary beings, and more magical happenings, along with less high-order cognition and less connection to ordinary daily surroundings.” (p. 165)
These findings are very similar to the SDDb baseline results. They give me confidence that these differences between MRDs and MemDs are real and not the result of random variations in the data.
The comparison with the 2011 study is not perfect, since a) that project did not adjust the dream reports for word length, including reports of less than 50 and more than 300 words, unlike the SDDb baselines, b) some aspects of the conclusion (e.g., intense imagery, nightmarish emotions) were derived from Hartmann’s Central Image scoring system and did not emerge from the word search analysis, and c) the participant pool had a big gender imbalance (147 female, 15 male). However, the mostly female composition of the 2011 study actually points to an even closer alignment with the SDDb female results because the female MemDs (but not the male MemDs) have higher frequencies of fire, falling, and physical aggression, all of which seem consistent with the 2011 study’s conclusion.
In a future post I will look at the SDDb’s high-frequency MemD elements–flying, air, family, animals, fantastic beings, Christianity, death–to try and discern what each of them adds to the dream’s memorability and impact on the dreamer.