SCENARIO: You plan to facilitate a discussion in your class about readings that you assigned. As students enter the room and settle into their seats, you can feel the buzz in the air. They are excited. They want to discuss the subject. You begin class by asking a very open-ended question, a question designed to allow the students to take the subject in an area that interests them. The first student who responds to your question, a question that is barely out of your mouth, is Nancy, or as her classmates call her, “Know-it-all-Nancy.” Nancy is a smart young woman who often has very smart things to say about the subject at hand. She answers your question with great precision, citing arguments from sources you did not require her to read. You know from experience that if you stand by quietly and let her finish, class would be over and no one else would have had a chance to speak. So, you cut her off—politely—to get other students involved in the discussion. You ask another question, directed at another student. Nancy answers.
This is a common problem in a high school age class. Students are diverse in their engagement and extra-curricular work, and some students who potentially 'over' prepare and want credit for it can be as disruptive as students who have not prepared enough. I classify this behaviour as 'disruptive' in the PBIS model.
The student is not being defiant in the normal sense, they are attempting to have their work recognised, in some ways, rightly. The issue is a social one, wherein the student is dominating the class to the detriment of the others, who may not have already gotten it, and so interventions want to focus on that aspect, and attempt not to discourage her from doing the good work she is doing.