For each object and demonstration, the infant’s behavior was video-recorded for the
duration of the trial. In all tasks, infants were given 60 s to produce responses, after
which the response period ended. Responses during the response period were
classified by a primary coder who was naive to the experimental hypotheses as either
imitation or emulation. Imitation was counted if the infant reproduced the particular
action of the experimenter. Because children had difficulty in using their elbow at
times, any action that involved the back of the hand or arm or the elbow was counted
as imitation for the doorbell task. Emulation was counted if children attempted to
produce the outcome (ring or illumination) using a standard familiar action such as
pushing with a finger or the palm of the hand. Responses were coded in two ways.
First, because many children performed more than one response during the trial, we
coded for whether any imitation/emulation occurred during the response period (any
imitation and any emulation) or whether the infant failed to respond (no response).
Second, responses were coded for the first response performed during the response
period (imitation first, emulation first, or no response). In this way, each trial was coded
both for whether the child performed an imitative action and for whether the child
performed an emulative action during the response period.