Mind & Brain See Inside Coming to Attention How the brain decides what to focus conscious attention on By Andreas K. Engel, Stefan Debener and Cornelia Kranczioch, Stefan Debener and Cornelia Kranczioch GETTY IMAGES With an impish smile, the professor announced that he was about to carry out a little experiment. He asked his class to watch a short video of two basketball teams and to count how many times the players in white T-shirts passed the ball. The students found that it wasn't easy to keep their eyes on the moving ball, but most of them believed they counted correctly. After the show, the teacher turned to face everyone again: "What did you think about the gorilla?" There was a shocked silence. He restarted the video, and after a few seconds a collective groan rippled through the room: as the audience now realized, a person in an ape costume had walked right across the court, pausing in the middle to pound on his chest. This is only a preview. Get the rest of this article now! Select an option below: Buy Digital Issue Customer Sign In *You must have purchased this issue or have a qualifying subscription to access this content It has been identified that the institution you are trying to access this article from has institutional site license access to Scientific American on nature.com. Click here to access this article in its entirety through site license access. ADVERTISEMENT Scientific American is a trademark of Scientific American, Inc., used with permission © 2013 Scientific American, a Division of Nature America, Inc. All Rights Reserved.