Ever have to walk over to your kid and tap him on the shoulder to get his attention? "I called you like seven times!" you say. He says with doe-like eyes as he puts down the x-box controller "But I didn't hear you!"
He's actually sort of right. His ears heard but his mind was a thousand light years away... He was in trance! It's normal and natural. He was not ignoring you. His attention was fixated elsewhere.