I've often described learning in terms of 'clicking'.

It's most memorable to me when thinking about hard problems that I can't solve right away. It feels like something finally puts the last piece of the puzzle in place and for the first time I can 'see' the answer.

When trying to teach people, I've noticed that some people have a very obvious 'click response'- they'll light up at a distinct moment and just get it from then on.

Other people show no sign of this, yet claim to learn. I still haven't figured out what is going on here. The possibilities I can think of are: 1) Their learning process involves no clicking 2) They hide the click to make it sound like they've known it all along because they'd be embarassed at how late their click is 3) They're faking it, and don't really get it.

For me though, learning about cryonics and the intelligence explosion idea didn't seem very 'click like' since it just seemed obviously true the first time I heard about it, rather than there being a delay that makes the evaporation of confusion more satisfying. I suspect the learning mechanism is actually the same though.