Here's the face of an early childhood-gifted person who truly understands that dealing with infants is two fold: (1) understanding different temperaments and (2) understanding goodness-of-fit (Berk, 2007; Gonzalez-Mena & Eyer, 2007).
Berk, L. (2007). Infants and children. Upper Saddle River, NJ: Pearson Allyn Bacon.
Gonzalez, J. & Eyer, D.M. (2007). Infants, toddlers, and caregivers. NY: McGraw-Hill.