ABSTRACT
Abilities to track actions and mental states, and to perform joint actions, appear about as early in development as abilities concerning physical objects. This should be no surprise given how social most humans are. The real headline from the discoveries reviewed is about limits, not successes. One kind of puzzle concerns abilities whose manifestation is response-dependent. For goal tracking and mindreading, there are single scenarios in which infants will manifest a goal-tracking or mindreading ability when one response is measured but not when another response is selected. Whereas puzzles about goal tracking and mindreading arise prior to accepting any theory, the main puzzle about joint action was linked to a particular theory. The general approach to solving the puzzles about goal tracking and mindreading we have followed leans on the idea of a dual process theory.
