This was back in the early 70s, I was sharing my place in Michigan with a couple of roommates, two dogs and three cats. My favorite was Sam, a big black cat who slept with me every night.
On one particular night I was unable to locate the land of dreams. I was awake and apparently I was going to stay awake. Sam, on the other hand, settled down by my left hand got a good dose of ear rubs and was sound asleep in minutes. I laid there for an hour, then two... somewhere in the middle of the night I was drifting a bit, not asleep yet. Sam woke up, stood up, stretched then walked across my chest and laid back down with his head in my right hand and I reflexively started petting him.
At that moment I realized he did this every night, maybe more than once. He had me trained, the paw impressions on my chest made my sleeping conscious aware of him without waking me up and when he put his head in my hand I would subconsciously scratch him until he fell back to sleep.
Trained by a cat while I was asleep. And they say dogs are smart.