Dream report length is more dependent on arousal level than prior REM duration.
Brain Research Bulletin 1994 Nicholas Rosenlicht, T Maloney, Irwin Feinberg
Twenty two young adult subjects (Ss) were monitored for 2 consecutive nights in the sleep laboratory. Each S was awakened three times per night: at sleep onset and during the second (REMP2) and fourth (REMP4) REM periods. Length of time in each REMP prior to awakening was either 5 or 10 min, counterbalanced on successive nights. Sleep mentation reports were obtained by standardized interview...