In addition to its practical significance, research on sibling relationships in families with disabled children also may provide important insights about "normal" sibling relationship processes. This is based on the assumption that experiences common to most sibling relationships may be particularly salient in families with disabled children. For example, some writers (e.g., Crocker, 1981; Powell & Ogle, 1985) have suggested that the special needs of a disabled child mean that sisters and brothers in these families are more frequently involved in sibling caregiving activities and/or are expected to spend more time supervising and entertaining their disabled siblings. The affective tone of sibling interactions also may be affected by a child's disabling condition. Limitations in a child's communication skills, self-control, or social understanding, stemming from cognitive or physical disabilities, may set the stage for more frequent sibling conflict. Alternatively, in some sibling dyads, a child's disabling condition may elicit more need and opportunity for prosocial and altruistic behavior on the part of a nondisabled sister or brother. Finally, the special care disabled children often require means that many parents must devote
extra time, attention, and family resources to these youngsters, possibly at the expense of the interests of other nondisabled siblings in the family. In turn, such differential treatment may lead to feelings of rivalry, jealousy, or hostility by nondisabled brothers and sisters. By studying families in which sibling activity patterns, sibling interaction styles, parents' differential treatment, or other sibling relationship processes are altered in important ways, we may highlight the central dimensions of children's sibling relationship experiences.