“…However, Kraaimaat and Janssen (1985) have pointed out that support for this contention is somewhat limited since it rests predominantly on studies which have shown that secondaries can be brought under stimulus control (Brutten & Shoemaker, 1967;Martin & Siegel, 1966a, 1966b. In addition, Kraaimaat and Janssen (1985) pointed to both Lanyon's (1978) suggestion that at least certain nonverbal accessory behaviors might be a result of speechassociated physical struggle and their own contention that some secondaries could be a physical result of classically conditioned speech anxiety (Janssen & Kraaimaat, 1986). In any event, Kraaimaat and Janssen's (1985) investigation of the oro-facial structure of the segments of their participants' speech that was fluent, normally disfluent or stuttered led them to conclude that "the actual function of the nonverbal behaviours emitted by stutterers is not fully clear" (p. 16).…”