2.4. Passive interaction probes (PIPs)
Passive interaction probes (PIPs) consisted of 90-min sessions during which each child’s social and communicative behavior
was observed. These probes took place in the playroom of each child’s apartment with only the child and a female examiner,
who used a passive style of interaction (after Wimpory, Hobson, & Nash, 2007). Seated on the floor in the corner of the playroom,
the examiner quietly doodled on a pad of paper while covertly attending to the child’s behavior, making no attempts to interact
with the child. When the child initiated a social interaction by using a communicative act (i.e., head orientation (look) toward
the examiner, use of communicative gesture or vocalization, the examiner responded immediately to the child with an