For fun -- I'd bet that can't is the contraction for can not, not cannot. I think cannot is sort of modern.
Sorry. It's late. I'm bored.
Hey, mn78, have you read Michael Lewis's, 'The Undoing Project'? I'm about 70 pages in and, as with all of Lewis's books, I recommend it. So far, much of what I've read reminds me of all the JS discussions over the years; more specifically, Mike McQueary, what he heard, what he saw and his recall of those things.
"The human mind was just bad at seeing things it did not expect to see, and a bit too eager to see what it expected to see."
"Of Danny Kahnemann's many doubts the most curious were the ones he had about his own memory. He'd delivered entire semesters of lectures straight from his head without a note. To his students he'd seemed to have memorized entire textbooks, and he wasn't shy about asking them to do it, too. And yet when he was asked about some event in his past, he'd say that he didn't trust his memory and so you shouldn't, either."
"Why does a person's understanding of what he sees change with the context in which he sees it."