Barry knew Alice was tired, but he was surprised that the argument between their three-year-old twin boys did not awaken her.She had not been asleep very long and occasionally changed her position, but did not wake.Alice is probably in
I searched Google under the key words "sleep stages & environmental awareness" to get this source:
http://www.healthyplace.com/other-info/sleep-disorders/sleep-basics-why-we-sleep-and-how-sleeping-works/
"Stage N2 sleep is characterized by a complete loss of environmental awareness and this stage occupies 45% - 55% of adult sleep."
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.
Alice is probably in a deep sleep stage, which is why the argument between their twin boys did not awaken her. Deep sleep is a phase in the sleep cycle where the body and brain are at their most relaxed state. During this stage, people are less likely to be woken up by external stimuli such as noise or movement.
To understand why Alice is likely in deep sleep, we can consider the factors mentioned in the passage:
1. Barry knew Alice was tired: Tiredness can contribute to falling into a deeper sleep, as the body and mind seek more restorative rest.
2. She had not been asleep very long: When a person has recently fallen asleep, they may be in the beginning stages of sleep, which are typically lighter and easier to wake from.
3. Occasionally changed her position, but did not wake: Movement during sleep is common and can indicate different sleep stages. If Alice is changing her position without waking up, it suggests that she is likely in a deeper sleep stage.
It's important to note that this analysis is based on the given information, and everyone's sleep patterns and experiences can vary.