“What to do with too much information is the great riddle of our time.”
Theodore Zeldin, An Intimate History of Humanity.
Zeldin’s not a psychologist. And I think we can go somewhere with this!
Now I’m in danger of giving my conclusion half-way through, so I’ll be brief.
The brain has limited processing capacity and bandwidth to shunt information even from one side to the other. Far less than would be needed to assess all the light that enters our eyes, even.
That capacity has to be allocated sensible, to what matters most.
Sometimes attention is allocated deliberately, like you focusing here.
Sometimes your brain helps out, and it’s allocated automatically… aiding, or despite your conscious mind.
What we call attention is the subjective feeling of giving something more processing time.