Aims:
To investigate interactional synchrony between infants and caregivers.
Procedure:
They conducted a series of controlled observations using babies (6-27 days old).
The babies were exposed to 4 stimuli, 3 facial gestures, and 1 manual gesture.
The babies' response to these gestures was observed and filmed.
An independent observer, who did not know what the infant had just seen, was asked to note all instances of tongue protrusions and head movements using some behavioural categories.
More than one observer scored the recording (greater inter-rater reliability).