So, it’s a little known fact that captchas and such like no longer test to see if you can solve something, because the bots have evolved to pass those kinds of tests.

They also tried to set them up to succeed where humans failed, but then bots evolved to pass those, too.

So now they look at how you fail or pass, or how you keep trying. Basically, they’re checking if you’re human by seeing how you respond to frustration.