Estimation of empty time.
Nine subjects maintained for 60 h in an environment characterized by "unfilled" time were requested to estimate the time of day throughout the period. Actual intervals to be estimated ranged from 5.2 to 23.5 h. Subjects tended to underestimate elapsed time, with the mean subjective hour continuing for 1.12 h in real time. Only 21% of all estimates of time of day were accurate. The state in which an interval was spent (sleep or wakefulness) influenced time estimation, as did the degree to which the sleep/wake cycle was disrupted. The data are interpreted as indicating that the degree to which an interval is "filled" or "unfilled" does not directly affect the manner in which the interval is perceived.
D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm; D006801:Humans; D012146:Rest; D012890:Sleep; D013998:Time Perception; D014851:Wakefulness