“…In experimental laboratory research on dreams, day residues play an important role. A few controlled laboratory studies have used artificial day residues in order to investigate how unconscious stimulus material is processed during sleep and how the contents reappear in waking free imageries, as well as in dreams (c.p., Fischer 1957(c.p., Fischer , 1958(c.p., Fischer , 1960(c.p., Fischer , 1988Leuschner 1986Leuschner , 1999Leuschner et al 1994Leuschner et al , 2000Shevrin 1986Shevrin , 2000. When presented subliminally (within less than 8 ms), no conscious perception of stimulus material was possible.…”