The simplicity of it is logic defying. It used to be that you had to find crosswalks or move puzzle pieces or type blurred letters and numbers, but NOW all the sudden I can just click a box and HEY!, I’m human?
That’s hardly the Turing Test I’d expected.
These type of “captchas” look at your browsing behavior. It is sort of a “trade secret” of what it looks for, but it might be screen resolution, mouse behavior, cookies, OS, time to click, etc. Anything a website has access to that would look different from a bot.
Yes, and it gives you (or the bot), a score.
If you don’t meet the score, is highly likely that you are a bot.
You can have a superficial an yet interesting read on the topic on the Google re-captch dev docs.
It is likely you are a bot, and then you get one it these regular captchas and the that will increase your score if you succeed.*