Evaluation: developmental importance (caregiver-infant interactions)
Observing behaviour doesn't tell us its developmental importance.
Feldman states ideas like synchrony only give names to patterns seen in caregiver-infant interactions.
These observations don't tell us the purpose of the behaviours and therefore can't tell us the importance of them in development of infants.
Can't be certain from observational research alone that reciprocity and synchrony are important for a child's research alone.