Human beings acquire information both from biology and culture in the acquisition of various social cognitive milestones (Kaye, 1982; Tronick, 2003). Just like other animals, humans have innate predispositions that not only contain the blueprint for physical maturation but, unlike many animal species, human infants have domains that contain sets of representations that sustain a specific area of knowledge such as language, number, and physics (cf. Karmiloff-Smith, 1992), but also sociality (cf. Legerstee, 2001b). The domain responsible for an understanding of people may not develop like other universal endogenous developmental processes, often involuntarily and without planning. I like to argue that the development of an awareness of the mental states of others requires considerable social interaction in order to develop into the complex capacity that it is. However, not all environmental and social interactions are beneficial or important for ToM development. Therefore, the specific social domain contains knowledge of people, but also domain specific constraints that propel infants to focus on input that is specific to people and their mental states. Thus the endogenous processes or predispositions facilitate engagement in pre-linguistic dyadic communication. During these interactions, infants share emotions and imitate the expressions of people, thereby enhancing mutual awareness and promoting identification with social partners. The endogenous processes allow infants to adapt to, and to learn from, the external environment, to optimize and also to recognize exogenous factors that are especially important for ToM development.