“…Class 1 variables include those external physical and psychosocial environmental events that, when present, instigate or increase the likelihood that the problem behavior will occur. These conditions may include such factors as reduction in the frequency of staff attention (Carr & Durand, 1985), presentation of demands (Carr, Newsom, & Binkoff, 1980), social disapproval (Mace, Page, Ivancic, & O'Brien, 1986), peer taunting (Cole, Gardner, & Karan, 1985), and removal of positive conditions (Peterson & Peterson, 1968). Assessment must be individualized as emphasized by findings reported by Mace and colleagues (1986) (1985) revealing obvious individual differences among persons with mental retardation in the types of antecedent conditions that instigate aggressive and related disruptive behaviors.…”