Verbal Behavior: Extended Edition. Chapter 15: Self-Editing. Quote 19

The processes of editing generated by punishment greatly increase the appropriateness of verbal behavior to all features of an occasion, including the audience. Unfortunately, however, the consequences are not always so happy. Stuttering, stammering, mutism, stage-fright, emotional confusion, and a general low level of verbal behavior with a loss of all its advantages may follow. (p. 380)