Cross-sectional research conducted on 96 mother-sibling-sibling triads found a strong link between personality traits and early adolescent sibling relational quality (Stocker, Dunn, & Plomin, 1990). Those personality traits that had a positive effect on relationship quality were a shy older sibling, a sociable younger sibling, a low frequency of upset in both the older and younger sibling, and a short duration of upset for the younger sibling. Those personality traits that had a negative effect on relationship quality were a high activity level of the younger sibling, a younger sibling prone to fits of extreme anger, and a younger sibling with an overall high level of anger. Cross-sectional research on 40 same-sex sibling dyads with the oldest sibling nearing adolescence found that children high in emotionality and activity and low in persistence tend to direct more negative behavior towards their sibling (Brody, Stoneman, & Burke, 1987).