I learned long ago that our five senses are so designed so that we pay special attention to changes in our environment and ignore steady-state conditions. I'm guessing our consciousness understands that we can't be hyper-vigilant all the time so when nothing new is going on we figure that we're safe and secure and that we can zone out a little bit. The example I use is the Crying Baby. If you try to ignore the Crying Baby . . . well . . . good luck with that. My Higher Power, ever the Merry Prankster, installed not one but two Crying Babies on my trip home so I could practice the arcane art of Not Giving A Shit. I was grateful that these were daytime flights and I wasn't trying to get a lot of sleep but it was still an amazing exercise in the art of Believing My Own Bullshit. I noticed that the second Crying Baby would wail normally on the out breath but had a staccato four or five step inhalation. It was mesmerizing. It made me laugh a few times.
Huff-Huff-Huff-Long Wail.
The kid was good. He seemed to be able to do other things while he was wailing. He was multi-tasking. He didn't even seem to pay attention to his wailing. He might have been so bored he put the wailing on auto-pilot. Maybe he was looking around the plane to see if he could find a content infant to outsource his own wailing. That way he could happily watch a video while still annoying everyone on the plane, except for his parents, who were so used to this kind of behavior that they just zoned out and ignored the wailing.
Huff-Huff-Huff-Long Wail.
Such problems I have.