selective attention test

During the summer holidays I read a rather insightful book called the invisible gorrilla the video above here demostrates one of the points made in the book. Watch carefully and count how many times the people in the white shirts pass the ball to each other before reading on....

Did anybody see the Gorrilla? When I first watched this clip I did. But not everyone does. It doesnt mean anything where you do or you don't. However it is shown that if some people aren't expecting to see something they might miss it.