Most of the weaknesses of discussion as an aid to learning, however, result from the failure of the teacher to use the method with skill and the failure of the students to take on the roles of good discussion group members. Usually lack of knowledge of what is required is the basic cause, but occasionally there may be a deliberate misure of the method by either teacher or students. Thus a teacher with a group of students wanting authoritative guidance may be tempted to use discussion as a way of leading them to his own views, a process which is really one of manipulation, and similarly some articulate students may use the discussion as a vehicle for the conversion of others to their own beliefs, the classroom becoming a platform with a relatively captive audience. A more thorough knowledge of discussion techniques may give some protection agains misuse and will certainly assist the teacher trying to get the maximum benefit from the method.