The phenomenon of not remembering or feeling the moment of falling asleep is known as "sleep onset amnesia" or "hypnagogic amnesia." Several factors contribute to this experience:
Transitional state: The process of falling asleep involves transitioning from wakefulness to sleep. During this transition, our consciousness gradually changes, and our awareness of external stimuli diminishes. As a result, we don't usually retain clear memories of this period.
Dissociation: Falling asleep is associated with a decrease in overall cognitive activity and a shift in brain wave patterns. This altered state of consciousness can lead to a sense of dissociation from the external world, making it difficult to retain conscious memories of the moment of falling asleep.
Short-term memory consolidation: Memory formation during sleep onset is affected by the gradual shift from wakefulness to sleep. The consolidation of short-term memories into long-term memories relies on specific brain processes that might not be fully active during this transition.
Attention and focus: As we relax and drift into sleep, our attention and focus decrease. The lack of focused awareness can lead to a lack of memory formation for the moment of falling asleep.
Sleepiness and drowsiness: As we become more tired and drowsy, our cognitive processes slow down, making it challenging to maintain continuous awareness.
It's important to note that while we might not remember the exact moment of falling asleep, we can still experience various sleep-related phenomena, such as dreams, sleepwalking, or sleep talking during different stages of sleep. Sleep is a complex process with several distinct stages, and each stage contributes differently to our overall sleep experience.