We develop a Roy model of social interactions in which individuals sort into peer groups based on comparative advantage. Two key results emerge: First, when comparative advantage is the guiding principle of peer group organization, the effect of moving a student into an environment with higher-achieving peers depends on where in the ability…

Affirmed that verbal behaviors (time speaking, initiated assertions, referrals received and first-person statements) were related to self-traits as measured by personality measures and a subjective self-report. The results are indicative of a proactive-reactive dimension of social interaction from both self and behavioral perspectives. (Author)