These two behavioral areas are very similar; both areas focus on communication but the difference is in the intent of the communication. The Social Communication items focus on a child’s ability to communicate to express interests, wants, or needs while the Interaction items focus on a child's ability to socialize and interact. For your reference, Table 3.3 on pages 33–35 of the ASQ:SE-2 User’s Guide (also available online after free registration) provides a list of specific items associated with each behavioral area by ASQ:SE-2 interval. For additional user-friendly explanations of the seven behavioral areas of ASQ:SE-2, you can also refer to this newsletter article.