“…The irregularity with which neurological and EEG examinations have yielded any diagnostically reliable difference appears to be evidence against an organic basis. Some authors (Prabhakaran, 1970;Stevens & Blachly, 1966) suggest a possible interaction or combination of functional and organic faccors, based primarily on the reported success with drug treatments. As a result of Yates' (1958) early work, tics have more recently been viewed as learned responses (habits) and treated within the frarnework of Hullian learning theory (Clark, 1966;Rafi, 1962;Thomas, et al, 1971;Yates, 1970) ; or as operanc responses which could be modified by the manipulation of the response consequences (Barrett, 1962).…”