Ok, this still doesn’t explain why a cat who has never had cat food from a can which used a can opener responds to the sound of a electric can opener. True story. My cats, who have never had a can from a can opener, run to me when I hit the electric opener. I raised them from little wee ones, so I know exactly what they have been exposed to. If I am looking from one of them, I can simply go to the can opener, hit it, and out they come. Weirdness prevails.