That’s the idea of those “which pictures contain bikes?” ones and the ReCaptcha (where you had two words from books). In the book one, one of the words is known and the other is not. They’ll present the same unknown word to people until they get a clear answer from many dozens or hundreds of entries, using the known word as a control. Then that other word goes into the known words category.
That’s the idea of those “which pictures contain bikes?” ones and the ReCaptcha (where you had two words from books). In the book one, one of the words is known and the other is not. They’ll present the same unknown word to people until they get a clear answer from many dozens or hundreds of entries, using the known word as a control. Then that other word goes into the known words category.