One of the things that Middle Son has done over the years is teach me to pay attention.
I remember reading that people with low-functioning autism live in a world of their own. That is certainly my experience with Middle Son. I often describe him as living at right angles to the rest of humanity. Occasionally he touches down on Planet Consensual Reality, but unless you are are paying attention, you won't see it and you will miss out on the chance to connect with him.
When Middle was born we had a Golden Retriever named Brandy. Brandy was amazingly tolerant of Middle Son. I remember watching him plant a knee in her eye socket and climb over her head, and she didn't even flinch. But I couldn't tell if Middle was aware of her as anything other than an obstacle on the floor.
The summer that Middle was 3 we had Brandy shaved so that she wouldn't be so hot, or leave so much hair all over the house. Shortly after, I saw Middle walk up to Brandy and poke her very gently with one finger.
He had noticed that she looked different. That showed me that he was in fact aware of the dog. He only did it that one time. I could easily have missed it. And then I wouldn't have known.