When I was a child, like 4 years old or so, when I wanted to get my mom's attention to tell her something, I would say, "Mom, Mom, Mom". I could see that she was looking straight at me, but I would keep calling her until she verbally said "What?" To me. Like, almost as though I didn't believe that I really had her attention until she would verbally reply. I think eye contact is essentially the adult neurotypical analogue to that. Without eye contact (mostly when you're being spoken to), peeps struggle to believe that you're tuned in