Even a single dead pixel would seriously distract me but he didn't even notice the gif of some disgusting medical scam ad showing elbows or knees or whatever.
He could also fall asleep seconds after hitting the bed. I need at least 10 minutes - at least. Sometimes an hour. Maybe it's a related phenomenon.
Some people just seem to ignore external stimuli better than others. Whether ads whose purpose is brand recognition work on them subconsciously, idk.
I tend to catch almost everything on the screen when I'm taking it in, and if someone asks me about something on the screen I can generally find it in a small fraction of a second; I don't take in every last detail (e.g word of text) simultaneously, but I have every major UI element in mind. I have observed that many people are focused specifically on one thing and don't notice a thing I call attention to without searching the screen for multiple seconds.
When introducing non-computer people to a new application, I find it helps (or is sometimes necessary) to walk them through each part of the screen, explaining what it is for and how it relates to the others. If someone doesn't or can't retain that explanation, usually nothing will help them. But if they do/can retain it, I find even non-computer people are much quicker in noticing particular updates to the application's or OS's GUI.
