What is it called when you have to type in the letters to confirm you are a real person not a computer?

what is it called when you have to type in the letters to confirm you are a real person not a computer and they make memes with them like this one for example http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs923.snc4/73598_10150291593935112_538460111_15478264_1734971_n.jpg

Chaptcha.
(Seeing as you already have 5 answers telling you this, this won’t be helpful.But oh well!)

It’s called Captcha – and they use it b/c ppl run these things called ‘bots’ or ‘spiderbots’ to scan for forms and fill them out.Hope this helps! Good luck!

Captcha.

A captcha 🙂