An investigation of the dual image model structure of dreaming using vivid and vague images from tonic and phasic REM dream reports

Seligman and Yellen (1987) have formulated a dual imagery theory of dream production. They hypothesise that in dreams vivid imagery is independently physiologically generated and will be unconstrained by the plot of the dream, while vague imagery will be constrained as it is produced by a process of cognitive synthesis which integrates the visual bursts into a more or less coherent story. A study using 15 subjects who slept in a sleep laboratory for one night was used to test this model. Subjects were awakened during tonic and phasic REM periods of the night and asked to recall their dreams and to rate the clarity of \the last most vivid image\" and \"the most vague image\". This study examined three main groups of hypotheses related to Seligman and Yellen's (1987) theory of dream construction: (1) The differences in vividness or clarity of imagery between tonic and phasic REM (2) The differences in surprisingness of vivid and vague images in relation to the preceding plot and (3) Incorporation of events from the precious day in dreams and comparison of incorporation in vague and vivid imagery. The results supported the first hypothesis on the differences in clarity of imagery between tonic and phasic REM sleep. This finding is consistent with previous studies of tonic/phasic differences (Molinari & Foulkes 1969). In testing the second hypothesis it was found that there was almost no difference in ratings of the surprisingness of vivid and vague images in relation to the preceding plot. Furthermore vivid images were also judged to be context related when interchanged between two phasic dreams collected on the same night. The third hypothesis concerned incorporation of events from the previous day in dreams. It was found that there was more direct incorporation from the subject's own diary record than from a diary of a randomly matched subject. There was however no differential process in incorporation between vivid and vague images. Thus contrary to the Seligman and Yellen (1987) theory there is evidence that vivid images are at least partially constrained by a process of cognitive construction in the formation of a dream and there is no evidence of any differences in the cognitive constraint on vague and vivid images. The results of this study are not consistent with he Seligman and Yellen (1987) theory and instead implicate a process of cognitive construction in the formation of vivid as well as vague images."