Decreased initiative and increased negativism and irritability may lead to a decreased willingness to report events and to interact with other aircrew. Impaired Attention Fatigued and sleep deprived individuals have a shortened attention span and cannot concentrate on specific tasks with the same vigilance and sustained alertness as when they are rested. Intermittent dream-like intrusions of irrelevant thoughts cause lapses of attention and decreased ability to concentrate. As fatigue and sleep deficit progress, the duration and number of lapses of attention increase. A well-recognized sign of sleep loss is the inability to recall what you just heard, saw, or read.
Memory loss is limited to short term memory of recent events.
An individual who is fatigued and sleep deprived may remain confident about retaining messages, data, and events only to realize later that these have been forgotten. Loss of sleep for 24 hours impairs the acquisition of information and newly retained material. After 48 hours of continuous work there is a drop below 40 percent of baseline levels of performance on tests that require recent memory. During continuous work episodes speed and accuracy suffer. Speed is most often decreased in order to maintain accuracy, not necessarily as a slowing down of all responses, but more as an unevenness in response time.