Quotes from Barbara D. Bateman

Students frequently misbehave because they (1) want and need attention from adults and peers, (2) are trying to avoid a difficult or unpleasant task (too difficult, too easy, too boring), or (3) for some older students, revenge.

The more attention you pay to the behavior you want from students, the more it will happen.

The process of determining if the misbehavior was getting something the student wanted or was avoiding something he didn't want is called functional behavioral assessment or analysis (FBA).