Human time perception in temporal isolation: effects of illumination
intensity.
Chronobiology international, 14 (6):
585--596 (November 1997)Abstract
Living in isolation from time cues under relatively high and low light
intensities for a total (on average) of 24 days, 18 subjects estimated
the passage of time by "producing" short (10 to 120 seconds) and
long (1h) intervals throughout the experiments. The 1h productions
were independent of light intensity and highly positively correlated
with the duration of wake times. The short-interval productions were
markedly increased under high light intensity. In a subsample of
6 subjects, the interaction between effects of body temperature and
light condition on 10-second production was analyzed. Productions
were negatively correlated with body temperature. In both dim and
bright light, productions decreased by a factor of 0.7 per degree
C. In bright light, production was increased by a factor of 1.2 relative
to dim light. This effect was not mediated by body temperature, which
itself was on average slightly increased in bright light. Since subjective
time is slowed by bright light, objective time seems to pass faster
in bright light.