ARTICLE Vinciarelli_IEEETRANSACTIONSONAFFECTIVECOMPUTING_2012/IDIAP Bridging the Gap Between Social Animal and Unsocial Machine: A Survey of Social Signal Processing Vinciarelli, Alessandro Pantic, Maja Heylen, Dirk Pelachaud, C. Poggi, I. D'Errico, F. Schroeder, M. IEEE Transactions on Affective Computing 2012