“…Home observations are often used for studies of very young children's relationships with parents and siblings (e.g., Dunn, 1993;Perlman & Ross, 1997;Smetana, 1989), but are only rarely used to study peer relationships (for an exception, see Ross, Tesla, Kenyon, & Lollis, 1990). This study thus extends the existing literature on early peer relations, which has focused primarily on laboratory tests (e.g., Caplan, Vespo, Pedersen, & Hay, 1991;Eckerman, Davis, & Didow, 1989 ) or day-care and nursery school groups (e.g., Howes, 1988;Murphy, 1937). Some evidence for stability of toddlers' behavior in conflict with peers has been obtained in laboratory tests (Cummings et al, 1989;Hay & Ross, 1982;Keenan & Shaw, 1994), which suggests that the question of stability and change in early forms of aggression deserves more systematic analysis in familiar settings.…”