In a properly-run social skills intervention, there should be a skilled coach/instructor(s) (i.e., adult), skilled peers (models), and reinforcing natural environments (adults, peers, and systems). Ideally, one wants a combination of direct in vitro instruction and facilitated in vivo practice, transitioning to independent in vivo practice, reinforced by natural environments.
This is why growing up with skilled and involved adult caregivers (e.g., parents, grandparents, aunts/uncles, close-knit neighbors) and mixed-age peers (e.g., siblings, cousins, neighbors) is so effective.
I would contend that parents ought to be the ones teaching social skills, and that the history of humanity suggests that parents have been net more effective than third-party professionals.
We do, however, have to be reflective about our own social and familial experiences, observant about our children's individual profiles, and intentional about the values, habits, and attitudes inculcated into them.
