How are those recapcha thingies where you simply click on a box labeled “I am not a robot” supposed to weed out robots, anyway? I could see that the old style, with wonky fonts and broken letters and so on presented a challenge in pattern recognition, but one click on a box??
It’s actually checking things like your IP, various cookies that are set on your computer, and your browsing history. Bots don’t browse and click random things on the internet or accumulate a pattern of cookies from their browsing.
I believe that it actually analyzes the mouse movement as you click, and has other tests ready to show if it can’t identify that movement as unpredictable enough to be human.
And it only gives the “I am not a robot” checkbox to people it’s confident enough about (who have probably also, incidentally, also done many conventional captchas). Some folks still get the conventional crazy-font ones.
That was my understanding as well. I suspect they also look at reaction time - a robot may click it immediately.
The other day, I clicked that box as I was logging into my PS4 app. A pop up box then appeared asking me to click on all the pictures that have a street sign in them.
I thought that was strange. Its never asked me to do that before.
That is what it does when it is unsure. This photo identification is a harder problem for computers.
Also, no one has found any mouse hooks, and they wouldn’t work on tablets, anyways. It does seem to have to do with history and such, as said above
Google is of course protective of the actual algorithm.
Robots can’t lie. Duh! 
Huh. Very interesting!
“And it only gives the “I am not a robot” checkbox to people it’s confident enough about (who have probably also, incidentally, also done many conventional captchas).”
Nice to know I’m presumed human. 
LOL!