Since Postal (1971: 27–31) first used the term Tough Movement, a great deal of material on this phenomenon has appeared in print. In all of this research, there has been a widespread (often tacit) assumption that the characteristic - in fact, exclusive - triggers for Tough Movement are adjectives (e.g. tough, hard, interesting) and nouns (e.g. bitch, bear, snap). For example, Lasnik and Fiengo (1974: 568) list 21 common Tough predicates. Although their list is not meant to be exhaustive, it is a characteristic one, especially in that adjectives outnumber noun triggers two to one and half the nouns are limited to vernacular usage (the most frequent use of noun triggers probably involves obscene usage).