In sleep deprivation experiments,
subjects usually have few problems after the first
sleepless night, and they appear to be relaxed and
cheerful. They have more difficulty staying awake
during the second night, however, and are usually
severely tired by 3a.m. of the second day. They perform
more poorly on tasks that require a high level of
cortical functioning, in particular, on tasks that
require them to be watchful, alert, and vigilant.
If they are given long test problems to
solve, they will fall asleep but will
often deny having done so.
By the third day, the subjects appear tense. They
become very apathetic and are irritable when disturbed,
and will experience erratic mood swings. Although
they may follow the instructions of the experimenter,
they do so with little energy. By the third night,
they are unable to stay awake without special intervention.
By this time, periods of micro-sleep (subjects stop
what they are doing for periods of several seconds
and stare into space) are observed. During these periods,
their EEGs show brain-wave patterns typical of sleep.
Foreword
