A few years ago I watched a documentary about human behaviour, memory and attention
In the documentary a group of about 30 observers are asked to count exactly how many times a basketball is passed between 5 or so basket ball players. The observers are viewing the activity from the bleachers.
After about 30sec of passing the ball it is put down and the observers had to note how many times the ball was passed. They are also asked whether they recall anything strange occurring at all.
They averaged well in counting the passes.
Very few said they saw anything strange, of those who did only 1 or 2 had correctly recalled the strange occurrence.

The strange occurrence was a man in a Yeti suit running around the basketball court between the players! ........ And almost nobody saw it!

When the observers were shown the video of what actually happened they were shocked!

It shows us how limited our ability for observation really is. If we were consciously aware of how little we are aware of, we would struggle to function.

Sometimes when I think I can’t work through a problem and I can’t see the answer, I think of this documentary. It reminds me that there are infinitely more aspects I am not currently observing even though they are right in front of me.