Luke - the walking dictionary

DH was talking to Luke's primary teacher on Sunday and he was commenting on how smart Luke is and that the other kids think that he is really weird sometimes because of the big words he uses in class. As an example he related this story: A couple of lessons ago the teacher wrote a phrase up on the chalkboard and told the class to keep their attention on the words on the board. Then the teacher pulled out a candy bar and asked the class if he were to eat the candy bar if they could still keep their eyes on the chalkboard. All of the other kids responded and said that they would watch the teacher eating the candy bar. Luke though responded and said that he would watch the teacher eat the candy bar but he could still see the words on the chalkboard using his peripheral vision...

To which all of the other kids in the class asked, "What's peripheral vision?"