@axpert ,
"For most, in addition to the factors that you mention, the human body tends to go into a more relaxed state, at least for most people anyhow."
Definitely true for me, but tiredness creeps up on me a little earlier nowadays. However, if I can make it to after 2am I usually start to wake up again.
If most people are either morning larks or night owls, then I'm in the latter group, as I suspect that most music lovers are.
I think we can be sure Romeo wasn't wooing Juliet first thing.
"A simple environmental factor-darkness or a lack of light plays a significant roll to sharpen our hearing. This simple factor allows our brain to decrease visual processing and devote more focused cerebral attention to our hearing."
Makes sense.
There's just a lot less need to be on alert at night.
For a start there's no need to keep checking your smartphone every 20/30 minutes.
Or to worry about the doorbell ringing.