Why did half the people in a study miss a gorilla walking through a basketball game?
Focus hard on one thing and a gorilla can walk right past you unseen.
In Simons and Chabris's famous experiment, participants asked to count basketball passes were so focused on the task that about half failed to notice a person in a gorilla suit walking through the scene. When attention is fully occupied, unexpected objects - even conspicuous ones - can go entirely unseen.
Counting basketball passes, half of viewers never saw the costumed gorilla stroll across the court.
You don't see everything in your field of view - you see what your attention is pointed at.
Attention is a spotlight, not a floodlight - locked on your phone, you're blind to the rest.
You see what you aim at, not what's there.
Learn the idea and practice English at the same time.