When it became obvious that my father was going senile, my sister and I went out looking for good dementia homes. We visited one which looked promising (though Father eventually ended up elsewhere) and the head nurse showed us around. As it happened one of the patients came by and sat down by a piano and started playing. The nurse expressed her amazement at how speech and memory might be lost but the ability to perform music still remained. I noted to myself that the old lady actually did not play any specific piece, but rather stuck together disjointed phrases, executing ingrained motor programmes. I did get to see a lot of that over the following years, how for example greetings and thank-yous remained and were automatically executed at the right cues.
Another common “truth” I’ve heard a lot is that old people get worse short-term memory but have no problem remembering things that happened long ago. It struck me: Has anybody checked whether these long-term memories actually correspond to true events, or might they just as well be constructed there and then?