What I get from Trevarthen's theory of innate intersubjectivity (2010) and the theory of theory of mind (Perner, 1999) is that they don't agree.
A considerable number of studies in theory of mind development suggest that infants are cognitively egocentric, that is they cannot understand that others may have different thoughts, feelings and points of view than they do until the age of 3 or 4 when a shift in cognitive development occurs.
Trevarthen on the other hand states that a newborn's view of the world is already intersubjective, that is a newborn can share parts of his/her inner world (thoughts, feelings) with other people and sense other people's intentions.
I was having a disagreement with my developmental psychology professor who thought they were reconcilable if one does a proper conceptual analysis of the statements of each theory and the methods and data that they use to formulate their theories, but she did not get any more specific as to what can be defined alternatively and how can this be done to avoid conflict.
Any thoughts on that?