Final answer:
Social Development contributes to adolescents' increasing sensitivity with members of abstract groups.
Step-by-step explanation:
The developmental factor that contributes to adolescents' increasing sensitivity with members of abstract groups with which they have little experience is Social Development. During adolescence, teenagers spend more time with their peers, and peer influence and acceptance become very important. They may develop identities that align with a peer group, and conforming to their peer group becomes significant. As a result, they become more sensitive to members of abstract groups with whom they have little experience.