Two years ago, one of our RDI(r) objectives involved the concept of having conversations using just our faces. There are other ways to communicate non-verbally, but we needed to spend time on faces at that particular point in time.
Within a day or so of being assigned this particular objective (which is more specific than the version I summarized for you, here), I was driving the sibs to school, slowing down to make a right turn onto the street of the elementary school. That corner is quite busy, and there are children walking to school who cross that street from two different directions.
I've noticed over time (episodic memory) that the crossing guard stays in the warm comfort of her van until she is needed to escort children across the street, and if the crossing guard is standing outside her van, I can follow her gaze (perspective taking, attention shifting) and tell from which direction the students are walking.
One morning, the crossing guard was unusually close to the street, and her position alerted me to the idea that there were probably children approaching the crosswalk, and the silent conversation began.
I slowed down, prepared to make my right turn, and could tell from the direction of her gaze where the children were coming from, and they were pretty close to crossing the street where I was about to make my turn. So I had to shift my attention back to her, intentionally look to her, using my face to ask an unspoken but extremely important question, and receive an answer from her face and gestures. Was she going to let me go first, or was she going to have me stop, and let the children go first? We had to have a conversation using just our faces. She had to know that I saw her, that I would stop, before she would let the children cross the street.
Once I recognized several examples in my day where I relied on faces for conversation, I was ready to tackle the assignment and make some discoveries of my own. When a child doesn't take the initiative to monitor facial expressions, like I had to monitor the face of the crossing guard, the parents and professionals around that child behave differently, and we tend to overcompensate. I had to learn to quit feeding learned helplessness, use myself in new ways, so that my daughter could make some new discoveries.
What a different journey the developmental path has been...