Key points are not available for this paper at this time.
M. Katherine Weinberg, Edward Z. Tronick, Beyond the Face: An Empirical Study of Infant Affective Configurations of Facial, Vocal, Gestural, and Regulatory Behaviors, Child Development, Vol. 65, No. 5 (Oct., 1994), pp. 1503-1515
Weinberg et al. (Sat,) studied this question.