I am not sure I understand your issue with memory and mental confirmation. In the link I referenced earlier there is

This would conflict with my stored memory that 3 - 2 = 1

I imagine the situation as follows: I remember that 3 - 2 = 1, but I keep seeing that XXX - XX = XX. My observation contradicts my memory, so I keep repeating the experiment, but only see XXX - XX = XX. So I go to my girlfriend and show her my experiment. If she is seeing what I am, I'll ask her what is 3 - 2. If she says 2, then I will start doubting my memory. If she is seeing something else than I am, I will start blaming my senses. If she is seeing and remembering the same as I, I will investigate further and try to find what is going on..