Captcha, Turing Test, and Semantic Web
On the web nobody knows you are a dog, …… or a human. That’s why there are programs on the web to identify one as a human (from bots or dog or cats or……). Most popular ones are captcha. It is based on a simple assumption: no OCR agent so far can be as smart as a human is. To me, it looks like a super-simplified Turing test: an AI program has “real” intelligence as a human has, if being asked by the same question, another human can’t tell who is AI and who is human.
I can’t help imagining that one day, when OCR agents get smart enough to pass the captcha test (I strongly believe that day is not far away), what test we will use to identify a human on web. Math? That will be easy for a good program. Scrabble? maybe, but not that secure. Ask for a Shakespeare’s sonne? Or the end year of world war II? That looks more likely to succeed. But…There are two issues.
First, an agent may have access to a knowledge base. With projects like Dbpedia, human knowledge has been KBized in a speed never seen before in the history. A query as ” the end year of world war II” may be answered by a semantic web agent fairly quickly. I can imagine that someday we will have to design increasingly hard questions (like art things) to identify a human and fight spamming.
The other issue is that a human may have NO access to a knowledge base. Many, many people in the world does not know “the end year of world war II”, even if they may be knowledgeable in other things. They may not even know where to find such a knowledge. Also, they can get bored when been consistently asked such captcha questions and quit — technically, that means they failed the test thus are not “human”. When captcha becomes increasingly hard (like art things), more and more people may fail in one reason or another (including boredness). That will also lead to the failure of the identification system.
Will semantic web help spamming by designing smart agents? :) Maybe, let’s wait and see.
Jie Bao
Oops. the “T” in “captcha” really means “Turing”. I have been a fool for finding the new continent.
I like captcha with selection. Where you have, in example, 8 pictures and you have to select 3 kittens. I think it will be hard to pass it for a machine
Maybe the solution is in using jokes. I guess event the smartest AI agents are still far from having a sense of humor, and captchas would stop being boring with questions like “Which ones of these 5 jokes is funny?”. Sure it would mean that *people* with no sense of humor would be considered as non-human… but is there really such a thing as a human with no sense of humor?
To Mathieu: great suggestion. Though, we might need to take into account that humor is heavily culture-dependent. Many words are funny because we know their context (e.g., a movie), while somebody else may not..
To Nicholass: image recognition is also a good idea.
Where is captcha?
Строим дом
There’s an interesting way to generate semantic CAPTCHAs by a web service called Egglue http://drupal.org/project/egglue_captcha
There’s a module for Drupal, but not for Wordpress unfortuantely.