Developmental changes in interpersonal perceptions in older siblings were studied in children in grades K, 2, 4, 6, 8. Older children used more abstract and more nonegocentric modes of description. (ST)

Mothers were interviewed periodically over the first six years of their same-sex twins' lives and were asked to contrast them on specific behaviors. Intrapair contrasts were moderately stable across age spans for as long as 18 through 36 months. Genotypic similarity was apparently associated with intrapair similarity in emotionality and…