Catherine Weinberger writes,

while math scores, sports, leadership roles, and college education are all associated with higher earnings over the entire 1979-1999 period, the time trend in the earnings premium was strongest among those individuals who participated in sports or leadership activities during high school and had higher levels of cognitive skills. Supporting evidence based on Census and CPS data matched with the Autor, Levy and Murnane (2003) job-task measures provides an independent observation also suggesting that the labor market increasingly favors workers with strong endowments of both cognitive and social skills. These findings, coupled with evidence of growing employment, suggest increasing complementarity between cognitive and social skills among young workers.

Pointer from Tyler Cowen, who sees the findings in an average-is-over context. Indeed, if cognitive skills and social skills are both somewhat scarce and imperfectly correlated, increasing complementarity would lead to greater inequality.

I would always tell my AP Statistics students that they were learning technical communications skills. I would say that communicators without technical skills end up as baristas. Those with technical skills but poor communication skills will end up as Dilbert, working for a boss who appears to be an idiot.