I discuss three key differences between Pettit's philosophical genealogy and other influential works of cognitive development. They are: (i) concern with the temporal distribution of changes from a starting state A to the envisaged end state B, (ii) constraints on the specification of A and (iii) claims about the likelihood of the transition from A to B. I argue that legitimate concerns can be raised about Pettit's treatment of (ii) and (iii). Nonetheless, When minds converse proposes a series of original, compelling and empirically testable hypotheses about the role of conversation in cognitive development.
Richard Moore (Wed,) studied this question.