Mothers typically pick up and respond to their baby's alertness around 2/3 of the time, this varies according to the skill of the mother and external factors such as stress
From around 3 months, interaction tends to become increasingly frequent and involves mother and baby paying close attention to each other's verbal signals and expressions
Interactional synchrony has been observed in babies as young as 2 week old, where babies' expressions/gestures were more likely to mirror those of the adults more than chance would predict
recording interactions in a lab helps avoid distractions, allows for detailed analysis, can involve multiple observers and ensures natural behaviour for reliable data.
difficulty observing babies
poor coordination and limited mobility make their small movements and expression shard to read, so we can't be sure if these behaviours hold special meaning.
developmental importance
observing behaviour doesn't reveal its developmental importance. Feldman notes that terms like synchrony and reciprocity merely label observable patterns, without explaining their purpose.
counterpoint
evidence supports early interactions are important. E.G. Isabella found that interactional synchrony predicts good quality attachment. thus, caregiver-infant interaction is important for development.