Hoi!
One of my players is constatly arguing over matters which the rest of the group (including yours truly as the gm) consider self-evident or indemonstrable.
For example, she is positively confident, that your average Joe is very attentive to his surroundings, like, he will immediately spot a new ad on an announcement board near an entrance to his appartment building (like this:
http://img0.liveinternet.ru/images/attach/c/6/91/966/91966972_obyavleniya.jpg), or that he will immediately spot, that there is a new pen in his cubicle at work. Mind you: spot immediately and 10 times out of 10.
We tried proving otherwise with ADD statistics, with some random psychology and attention tests... All to no avail.
The sad thing is, it makes gaming with her somewhat... challenging. Like, "why didn't he spot the RFID tag on his desk? What, his perception is at -2 as he is distracted and he didn't roll good enough? Bullshit, it is obvious!".
And it's impossible to dissuade her. She never concedes, even if her last argument is "I don't buy it". One time we gave her a couple of articles on posttraumatic stress disorder, but she still considered it a myth.
Of course we might well be wrong on some points, but she never tries to prove her point, she just considers herself right a priori.
Could you offer any advice on the situation? She is our friend but it is becoming a problem.
Thanks in advance!