“…Here the categories were not mutually exclusive, either among themselves or in relation to those pertaining to adult activity and communicative role, and so combinations of the following categories might be coded: (a) social routines (adapted from Camaioni & Laicardi, 1985;Stone & Caro-Martinez, 1990;Watson, Lord, Schaffer, & Schopler, 1989) that comprised games, songs or nursery rhymes, and usually involved repetitive movement and sounds. These might be conventional (e.g., waving goodbye or peekaboo) or non-conventional (e.g., swinging the child around each time he or she came off the slide); (b) imitation of the child, either in action, body language, or vocalizations, but not including elaboration of what the child had said, nor merely imitating the child's intonation; (c) self-repetition, meaning one or more repetitions of any adult behavior within a turn, either in actions such as tapping something, body language such as mannerisms, or vocalizations such as occur in a repetitive refrain.…”