Reactions of male and female adolescent pairs to a same sex newcomer were observed as a means of assessing sex differences in indirect aggressive behaviors. Following a problem solving session, the group members rated each other's personality. Adolescent girls made less favorable judgments of the newcomer than did adolescent boys. In addition, on behavior interaction measures obtained during the problem solving task, girls displayed less friendly reactions than did boys toward the newcomer. These results, in conjunction with those of an earlier study, reflect developmental consistencies in sex differences in the use of indirect aggressive behaviors. (Author)