Inattentive blindness.

The term "inattentive blindness" was named by Arien Mack and Irvin Rock in 1992. to describe their results of studies about visual perception of unexpected objects.
What is inattentive blindness? It's a psychological lack of attention, but that is not connected with some visual defects. It's sort of failure of detecting something fully visible, because our attention is engaged to another task, object or event. It looks something like this for example; someone tells you to focus on something like counting ball passing trough two people, and your task is to count how many passes they made. Your mind will be so focused on counting that you will miss something obvious like gorilla walking by two people in front of your eyes. There is great example of this, video on youtube that show you exactly same thing that i wrote.

There is a lot more examples of this like:

1. When you are driving car, you think that you are so focused on road that you miss obvious, like car swerve into your line, something this result car crash.
2. Same is when you are trying to call someone on cell while driving (btw that is not legal :D) and you miss traffic light or at one second you don't hold your steering wheel and your car just go on side that sometimes result car crash.
3. There is also one pretty good magic trick. It's called cups and balls. You are so focused on cups that you don't see what magician do with balls. Some illegal street performers do this with boxes of matches, that make you follow little aluminium ball and when he stops with shuffle you need to place money on that box where you think its ball and you will probably lose money. I think that this is very familiar scam to you.

I'm gonna show you this video of Tedx talk in Vienna called "The art of cognitive blindspots" by Kyle Eschen, comedian and magician. It's pretty funny and yet so informative video.

Imagine an experienced pilot attempting
to land an airplane on a
busy runway. He pays close attention
to his display console, carefully
watching the airspeed indicator
on his windshield to make sure
he does not stall, yet he never sees
that another airplane is blocking
his runway!
Arien Mack