ON THE PASSAGE OF SUBJECTIVE TIME IN TEMPORAL ISOLATION

Data were collected in 48 experiments from subjects who lived singly i n an underground isolation unit without any temporal cues. By recordin g the sleep-wake cycle and rectal temperature, two states of the circa dian system could be distinguished: internal synchronization with equa l periods for the sleep-wake cycle and the rhythm of temperature (n = 33), and internal desynchronization either by a lengthening of the sle ep-wake cycle to more than 28 h (n = 12) or by a shortening to less th an 22 h (n = 3). Due to desynchronization, the duration of wake time v aried within the limits from about 10 to more than 30 h. The subjects were asked to press a button whenever they thought that one hour had p assed. The intervals produced in this manner were longer than 1 h, and varied in strong proportionality to the duration of wake time. This r elationship held intraindividually as well as between subjects. It is concluded that the passage of subjective time is closely coupled to th e sleep-wake cycle.