I don't mean inattentional blindness, where something is right in front of you but because of your attention being elsewhere you don't notice it at all and might deny it was even there if asked later.
I mean, when you idly, passively see something, and you do minimally notice it (if someone later asks "did you see X" you'll say yes), but it doesn't register, you don't process it properly or think about what you're seeing, you process it on autopilot.
Is there a word or simple, short, familiar phrase for that?
For example, earlier today over brunch, while my mind and the conversation were on other things, I saw a man walking a goat on a string down a main city road. I saw it, and I even idly, inattentively watched him tugging on the reluctant goat's string to pull it away from the fast-moving traffic, but it wasn't until my partner asked if I'd seen the man with the goat that I processed it at all and it registered that it was anything unusual.
I had seen it, I just hadn't observed it or really taken it in.
It's something often used for comic affect in film and TV, especially cartoons, especially as the setup for a double-take. I think a lot of disciplines like Asian martial arts and "mindfulness" regimes try to teach people against doing this. But I can't think what it's called.