Attention is the focusing on one thing while ignoring other things that may be going on at the same time. If you are able to continue reading a book without being distracted by children running and screaming around you, and a dog is barking and pulling at your pant leg, then you're maintaining your attention on the book. You have filtered out everything else to focus on one thing. If the dog finally bites your ankle, your attention would shift from the book and may become scattered when you realize the chaos that surrounds you. Attention was first defined in the 1950's by psychologist WIlliam James, but is still not completely understood.