Turquoise said: "...And someone should add that "witnessing sleep" may not mean shit. ... Such as that there is a subset of patients who complain that they "Never fall asleep." ... When hooked up to machines to monitor their physiology during sleep, these folks *are*, in fact, experiencing all of the classic cycles of sleep, along with their accompanying REM or lack of REM activity...."
Of the four stages of Non-REM sleep, in Stage 1, upon wakening, one may feel as if he or she has not slept. In Stage 2, muscles relax, we lose consciousness of the environment, etc as a preparation for deep sleep. This is not yet deep sleep and a sense of inner wakefulness in Stage 2 is more likely than in deep sleep. Stages 3 and 4 are the deep sleep states. However, as we age, Stages 3 and 4 become less, often significantly. Stage 1 and 2 of Non REM sleep are more conducive of the experience of being awake / conscious (though not necessarily of the environment). Those past 50 and / or with sleep disorders that reduce or eliminate stage 3 and 4 stage non REM sleep may be more likely to experience "witnessing sleep". Reduction or elimination of Stage 3 and 4 Non REM sleep is not a good thing. A strong Stage 3 and 4 sleep architecture is important for many sleep and waking functions. Lack of sleep (not exclusively stage 3 and 4, however, however weak stage 3 and 4 negatively affect other sleep stages) contributes to lower proficiency in most cognitive functions, including memory consolidation and working memory. Working memory is a highly critical factor in intelligence and performance across a wide span of activities. Lack of adequate sleep also contributes to attention disorders, including the tendency of the mind to wander, not being able to sustain attention on a focussed task. Sparaig points out that the study shows positive correlation of witnessing sleep with wandering mind -- which raises the question of whether (one of many possible hypotheses and models ) the states experienced by the subjects are due to reduced quality of sleep (poor stage 3 and 4 sleep architectured) resulting in attention deficits, reduced working memory capacity, and subsequent reduction of applied intelligence .
