The Canary
So, Atilla the wife and I owned a canary. It sat on a perch in a cage. It was well taken care of, with people talking to it all the time.
My contribution was: whenever I came near the bird, I would point above its head at the wall and say "SPIDER". After about 6 months, all I had to do was say "SPIDER" and the canary would look over its head.
One day, I walked up to the canary and said "SPIDER", the bird looked over its wing at the wall, and I noticed that Atilla the wife also looked up to the wall automatically.
Conducting more experiments, all the kids were breaking their necks to look at the wall, whenever I said "SPIDER".
I realized that they didn't notice that they were doing what the bird was doing. When I confronted them, they all denied it.
So I set up a video camera, and sure enough, the video proved they were well trained.