My wife asked me if I’ve ever heard of “signal detection theory”. I said “nup”, which surprised her. She reckons that you guys would have (I think she’s looking at you @Belfry ). It would be easy enough to ask ChatGPT (go ahead and laugh at me @techman ) but I think it would be more fun to ask all of you.
I’ve never heard of “signal detection theory”, and you’re way too big to laugh at 
I’m just a simple retired electronics technician!
I hadn’t heard of SDT before but anyone who has done a visual field test for glaucoma will know the problem. (Was that a faint flash way out at 7 o’clock??? Bugger it, I’ll press the button anyway.)